WO2026008743A1 - Water-soluble polyanionic polymer as adjuvant for carrier-formulated nucleic acid - Google Patents

Abstract

The disclosure relates to an immunogenic composition comprising at least one water- soluble polyanionic polymer, at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, and at least one nucleic acid encoding at least one antigen.

Description

[TITLE] WATER-SOLUBLE POLYANIONIC POLYMER AS ADJUVANT FOR CARRIER- FORMULATED NUCLEIC ACID [TECHNICAL FIELD] [0001] The disclosure relates to the field of immunogenic compositions comprising at least one nucleic acid encoding at least one antigen. The disclosure further relates to the field of adjuvanting such immunogenic compositions and to the field of dose sparing of the antigen- encoding nucleic acid. [TECHNICAL BACKGROUND] [0002] Vaccines are at the frontline of medical interventions for inducing protective immunity against various infectious diseases. mRNA vaccines have opened new avenues for the vaccine field. mRNA vaccines comprise messenger RNA (mRNA) encoding a target antigen, usually formulated in specific delivery systems such as lipid nanoparticles (LNPs). When an mRNA vaccine is administrated to a subject, the host cells will translate the mRNA into the antigen (protein), thus stimulating an immune response. While mRNA vaccines have demonstrated remarkable efficacy, particularly in the case of COVID-19 vaccines, many challenges remain. [0003] In particular, there is a need for mRNA vaccines with enhanced immunogenicity and efficacy, while displaying reduced reactogenicity and improved tolerability and safety profiles. While immunogenicity of mRNA vaccines can be enhanced by increasing the dose of mRNA used, reactogenicity is also correlated to the dose of mRNA, as it impacts the quantity of cationic or ionizable cationic lipid usually contained in LNPs to be used in the mRNA vaccine (the mRNA/lipid ratio being constant). The nature and quantity of cationic or ionizable cationic lipid is thought to be one of the major components of the reactogenicity of mRNA vaccines. Moreover, there is a need for effective mRNA vaccines using lower doses of mRNA encoding the antigen(s). Such mRNA dose sparing could provide advantages both in terms of safety and cost-effectiveness. [0004] The effectiveness of more traditional vaccines, such as vaccines comprising recombinant protein antigens, may rely on the incorporation of adjuvants for enhancing the immune response to the target antigen, by eliciting innate immune responses, connecting antigen to improved induction of adaptive immunity. In mRNA vaccines, adjuvants are often not added, due to the immunostimulating properties of the innate immune pathways induced by mRNA and the components of the delivery system (e.g. LNP) and the increased risk of increasing reactogenicity. Some strategies have more recently been proposed to improve adjuvanticity of mRNA vaccines. Xie et al. (npj Vaccines, 2023, 8:162; https://doi.org/10.1038/s41541-023-00760-5) present these main strategies, i.e., adjuvanting effect based on the intrinsic characteristics of mRNA, based on the components of the delivery system (e.g. cationic lipid of LNPs), or based on additional immunostimulants (e.g. cholesterol- modified cationic peptide DP7, or palmitic acid-modified agonist R848). The recent review by Mochida and Uchida (RNA Biology, 2024, 21(1), 1-27; https://doi.org/10.1080/15476286.2024.2333123) also describes the design of delivery systems for improving immunogenicity, such as the co-encapsulation of adjuvants and mRNA into the same nanoparticles (e.g. hydrophilic adjuvants in the water phase - being encapsulated with mRNA, or hydrophobic adjuvants in the lipid phase), the use of immunostimulatory cationic or ionizable cationic lipids in the nanoparticle, or the use of polyplex systems (wherein mRNA is complexed with a polymer) instead of nanoparticles. [0005] WO 2022/002783 discloses a method of eliciting an immune response in a subject, comprising separate administrations of a composition comprising mRNA encapsulated in LNP (on one hand) and of a squalene-based emulsion adjuvant (on the other hand). [0006] As reviewed in Mochida and Uchida (2024), other work has focused on delivery systems for enhanced expression of the mRNA-encoded antigen, rather than adjuvanticity. The review by Mobasher et al. (BBA - General Subjects, 1868 (2024) 130558; https://doi.org/10.1016/j.bbagen.2024.130558) discloses various delivery systems used for mRNA vaccines, including lipid nanoparticles, liposomes, and polymeric nanoparticles. [0007] Andretto et al. (Journal of Controlled Release, 2023, 353:1037-1049; https://doi.org/10.1016/j.jconrel.2022.11.042) disclose the use of hyaluronic acid (HA) for coating liposomes-mRNA complexes (lipoplexes). In lipoplexes, the RNA is added to the preformed liposomes and is at the end complexed with the liposomes to give a cationic delivery system. This document discloses the obtaining of an enhanced expression of the protein encoded by the mRNA. No immune composition and no adjuvant effect are disclosed. [0008] Zhang et al. (Acta Biomaterialia, 2024, https://doi.org/10.1016/j.actbio.2024.02.004) disclose the incorporation of poly (^-glutamic acid) (PGA) in LNPs for enhancing mRNA delivery efficiency. The PGA and the mRNA are first premixed and then added to the preformed LNPs under strong mixing conditions so that the PGA and mRNA appear to be encapsulated in the LNPs. This document discloses the obtaining of an enhanced expression of the protein encoded by the mRNA. No immune composition and no adjuvant effect are disclosed. [0009] However, as mentioned in the review by Mochida and Uchida (2024), in some settings, adjuvanticity, rather than antigen expression efficiency, may determine vaccination efficacy, wherein a vaccine providing enhanced immunostimulation and lower antigen expression outperformed that providing less efficient immunostimulation and enhanced antigen expression. [0010] There are still challenges in the field of nucleic acid-based vaccines, such as mRNA vaccines. [0011] There is a need for novel strategies of adjuvanting immunogenic composition (e.g. vaccine) containing nucleic acid (e.g. mRNA). [0012] There is a need for novel strategies of adjuvanting immunogenic composition (e.g. vaccine) containing nucleic acid (e.g. mRNA), allowing to enhance its immunogenicity and efficacy, without increasing reactogenicity. [0013] There is a need for novel strategies of adjuvanting immunogenic composition (e.g. vaccine) containing nucleic acid (e.g. mRNA), allowing to induce immune response at lower antigen doses, thus allowing a nucleic acid (e.g. mRNA) dose sparing effect. [0014] There is a need for novel strategies of adjuvanting immunogenic composition (e.g. vaccine) containing nucleic acid (e.g. mRNA), using a simple process. [0015] The present disclosure has for purpose to satisfy all or part of those needs. [SUMMARY] [0016] According to one of its objects, the present disclosure relates to an immunogenic composition comprising: [0017] - at least one water-soluble polyanionic polymer, [0018] - at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, and [0019] - at least one nucleic acid encoding at least one antigen. [0020] The water-soluble polyanionic polymer may be an adjuvant. [0021] The water-soluble polyanionic polymer may be present in the composition of the disclosure as an adjuvanting agent. [0022] The water-soluble polyanionic polymer may be present in the composition of the disclosure as an antigen-encoding nucleic acid dose sparing agent. [0023] As shown in the Examples, a water-soluble polyanionic polymer, such as a polyacrylic acid (PAA) sodium salt, was able to adjuvant an immunogenic composition comprising a nucleic acid, such as an mRNA, encoding an antigen and formulated with a nucleic acid carrier comprising a cationic, or ionizable cationic, lipid, such as lipid nanoparticles (LNPs). [0024] As shown in the Examples, the water-soluble polyanionic polymer was able to improve the immune response, while not increasing reactogenicity. For instance, similar immune responses were obtained with two immunogenic compositions differing from each other, in that the second immunogenic composition comprised a 20-fold lower content of antigen-encoding nucleic acid while it additionally comprised the water-soluble polyanionic polymer, compared to the first immunogenic composition. In addition, comparable magnitude of reactogenic effects were observed with the two immunogenic compositions (with potentially even lower reactogenicity for the second composition). Further, as shown in the Examples, the improvement of the immune response, while not increasing reactogenicity, was obtained with various cationic, or ionizable cationic, lipids contained in the nucleic acid carrier (e.g. LNP), such as OF-2 and GL-HEPES-E3-E12-DS-4-E10. Similar results were also obtained with other nucleic acid carriers (e.g. LNP), comprising MC3, SM-102 or ALC-0315 as the cationic, or ionizable cationic, lipid. [0025] Further, the Examples show that the water-soluble polyanionic polymer was able to achieve a dose sparing of the antigen-encoding nucleic acid. A dose-sparing of at least 4 was achieved. [0026] Still further, the Examples also show that the water-soluble polyanionic polymer was able to increase the immune response against each antigen when used with a combination of two distinct antigen-encoding nucleic acids and could allow to use up to 5-fold lower dose of antigen-encoding nucleic acids, while inducing similar immunogenicity levels against each antigen. [0027] As shown in the Examples, the improvement of the immune response was due inter alia to an adjuvanting effect, i.e., increased induction of proinflammatory cytokines and chemokines, and was not associated with an increase of the antigen expression. [0028] As shown in the Examples, the immune response induced by the antigen- encoding nucleic acid in presence of the water-soluble polyanionic polymer included a systemic response. The Examples also demonstrate that this immune response was specific to the antigen, and displayed a Th1-skewed profile. [0029] In some embodiments, the water-soluble polyanionic polymer is selected from the group consisting of polyacrylic acid polymer, polymethacrylic acid polymer, hyaluronic acid polymer, polyglutamic acid polymer, polyaspartic acid polymer, polystyrenesulfonic acid polymer, heparin polymer, dextran sulfate polymer, carboxymethylcellulose polymer, alginic acid polymer, combinations thereof, and pharmaceutically acceptable salts thereof. [0030] In some embodiments, the water-soluble polyanionic polymer is a polyacrylic acid polymer, or a pharmaceutically acceptable salt thereof. [0031] In some embodiments, the nucleic acid carrier is a lipid nanoparticle (LNP). [0032] In some embodiments, the nucleic acid is an mRNA. [0033] According to one of its objects, the present disclosure relates to an immunogenic composition comprising: [0034] - at least one water-soluble polyanionic polymer, wherein said water-soluble polyanionic polymer is a polyacrylic acid polymer, or a pharmaceutically acceptable salt thereof, [0035] - at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, wherein said nucleic acid carrier is a lipid nanoparticle (LNP), and [0036] - at least one nucleic acid encoding at least one antigen, wherein said nucleic acid is an mRNA. [0037] In some embodiments, the immunogenic composition is obtainable by a process comprising at least the steps of: [0038] (a) formulating at least one nucleic acid encoding at least one antigen with at least one nucleic acid carrier, wherein the nucleic acid carrier comprises at least one cationic, or ionizable cationic, lipid, thus obtaining a first composition, and [0039] (b) formulating the first composition obtained in step (a) with at least one water- soluble polyanionic polymer. [0040] In some embodiments, step b) may be carried out by gently mixing the first composition obtained in step (a) with the water-soluble polyanionic polymer. As used herein “gently mixing” intends to refer to a mixing which does not create shear stress and does not structurally affect the nucleic acid carrier, and the other components of the composition. [0041] In some embodiments, the nucleic acid is complexed with and/or at least partially encapsulated in the nucleic acid carrier. [0042] In some embodiments, the water-soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of 60 to 650 kDa. [0043] In some embodiments, the water-soluble polyanionic polymer is a linear or branched polymer. [0044] In some embodiments, the nucleic acid and the water-soluble polyanionic polymer are present in a w/w ratio from about 1:4000 to about 1:25. [0045] In some embodiments, the immunogenic composition comprises from about 0.1 mg to about 4.0 mg of water-soluble polyanionic polymer per dose. [0046] In some embodiments, the nucleic acid carrier is an LNP, said LNP comprising, further to the at least one cationic, or ionizable cationic, lipid, at least one stealth lipid, at least one structural lipid, and at least one helper lipid. [0047] In some embodiments, the immunogenic composition comprises: [0048] - a cationic, or ionizable cationic, lipid selected from the group consisting of OF- 02, cKK-E10, GL-HEPES-E3-E10-DS-3-E18-1, GL-HEPES-E3-E12-DS-4-E10, GL-HEPES- E3-E12-DS-3-E14, IM-001, IS-001, ALC-0315, SM-102, MC3, and combinations thereof; [0049] - a stealth lipid being a PEGylated lipid, said PEGylated lipid comprising a PEG moiety being PEG2000 (PEG-2K); [0050] - a structural lipid being cholesterol; and [0051] - a helper lipid selected from the group consisting of 1,2-dioleoyl-SN-glycero-3- phosphoethanolamine (DOPE), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2- dielaidoyl-sn-glycero-3-phosphoethanolamine (DEPE), and combinations thereof. [0052] In some embodiments, the stealth lipid is DMG-PEG2000, ALC-0159, or a combination thereof. [0053] According to one of its objects, the present disclosure relates to a vaccine comprising a prophylactically effective amount or a therapeutically effective amount of an immunogenic composition of the disclosure. [0054] According to one of its objects, the present disclosure relates to a kit-of-parts comprising at least a first container and at least a second container, wherein: [0055] - the first container comprises a first composition comprising at least one water- soluble polyanionic polymer, [0056] - the second container comprises a second composition comprising at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, and at least one nucleic acid encoding at least one antigen. [0057] The at least one water-soluble polyanionic polymer, the at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, and the at least one nucleic acid encoding at least one antigen of the kit-of-parts are as according to the disclosure. [0058] According to one of its objects, the present disclosure relates to an immunogenic composition according to the disclosure, for use in an immunization method. [0059] In some embodiments, the immunization method is for inducing an immune response with an antigen-encoding nucleic acid (e.g. mRNA) dose-sparing effect. [0060] In some embodiments, the composition may comprise an amount of the antigen-encoding nucleic acid at least 2 times lower than the amount of antigen-encoding nucleic acid of an immunogenic composition comprising the same nucleic acid carrier and the same nucleic acid and inducing a similar or comparable immune response in absence of the water-soluble polyanionic polymer. [0061] According to one of its objects, the present disclosure relates to a use of a water- soluble polyanionic polymer for obtaining an antigen-encoding nucleic acid (e.g. mRNA) dose- sparing effect in an immunization method, the water-soluble polyanionic polymer being included in an immunogenic composition comprising at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, and at least one nucleic acid encoding at least said antigen. [0062] According to one of its objects, the present disclosure relates to a use of a water- soluble polyanionic polymer for adjuvanting an immune composition, the immunogenic composition further comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen. [DESCRIPTION OF THE FIGURES] [0063] FIGURE 1 represents the size measurement by Dynamic Light Scattering (DLS) of LNP/mRNA, SPA09 adjuvant and LNP/mRNA adjuvanted with SPA09. Z-average diameter = mean particle diameter from three measures. PDI = polydispersity index. [0064] FIGURE 2 represents the design of mouse studies to determine HI titers in serum and clinical signs. Mice were injected twice, three weeks apart, by i.m. route with the appropriate doses of mRNA in LNP, alone or with different doses of SPA09 (polyacrylic acid polymer). Clinical signs were monitored daily after each injection. Blood samples were collected 2 weeks (d35) or 3 weeks (d42) following the second administration to assess specific Flu HI titers. [0065] FIGURES 3A-B represent: A): the HI antibody titers at day 42 induced in mice having received two i.m. injections (as described in Figure 2) of a 0.1µg-dose of mRNA encoding HA from A/Tasmania/503/2020 (H3N2) Flu strain (HA-H3 Tasm) in OF-02 LNP, alone or with a 200 µg dose of SPA09, in comparison with a 2 µg dose of the same mRNA in the same LNP without SPA09, using the same immunization schedule; and B): in the same mice as in Figure 3A, the clinical signs (like swelling, necrosis, redness in the right quadriceps at the site of injection, piloerection, unsteady state, and loss of motor function) were monitored daily after each i.m. administration until total disappearance of clinical signs. [0066] FIGURES 4A-B: represent A): the HI antibody titers at day 35 induced in mice having received two i.m. injections (as described in Figure 2) of a 0.1µg-dose of mRNA encoding HA-H3 Tasm in GL-HEPES-E3-E12-DS-4-E10 LNP, alone or with a 50µg-, 100µg- or 200µg-dose of SPA09. **: represents the p < 0.01. ***: represents the p < 0.001; and B): in the same mice as in Figure 4A, clinical signs (like swelling, necrosis, redness in the right quadriceps at the site of injection, piloerection, unsteady state, and loss of motor function) were monitored daily after each i.m. administration until total disappearance of clinical signs. [0067] FIGURES 5A-B represent: A) the HI antibody titers at day 35 induced in mice having received two i.m. injections (as described in Figure 2) of a 0.4µg-dose of mRNA encoding HA-H3 Tasm in GL-HEPES-E3-E12-DS-4-E10 LNP, alone or with a 50µg-, 100µg- or 200µg-dose of SPA09. **: represents the p < 0.01. ***: represents the p < 0.001; and B) in the same mice as in Figure 5A, the clinical signs (like swelling, necrosis, redness in the right quadriceps at the site of injection, piloerection, unsteady state, and loss of motor function) were monitored daily after each i.m. administration until total disappearance of clinical signs. [0068] FIGURES 6A-C represent: A) the HI antibody titers at day 35 induced in mice having received two i.m. injections (as described in Figure 2) of mRNA encoding HA-H3 Tasm, at a dose of 0.1µg (alone or with 50µg-dose of SPA09) or at a reference dose of 1.6µg, in GL- HEPES-E3-E12-DS-4-E10 LNP. ***: represents the p < 0.001; B) the HI antibody titers at day 35 induced in mice having received two i.m. injections (as described in Figure 2) of mRNA encoding HA-H3 Tasm, at a dose of 0.4µg (alone or with 50µg-dose of SPA09) or at a reference dose of 1.6µg, in GL-HEPES-E3-E12-DS-4-E10 LNP. *: represents the p < 0.05. ***: represents the p < 0.001. In both Fig. 6A and 6B, the dose-sparing was determined by comparing HI titers induced by the adjuvanted mRNA (at 0.1µg or 0.4µg), to those induced by the unadjuvanted mRNA at the reference dose of 1.6µg; and C) in the same mice as in Figure 6A and 6B, the clinical signs (like swelling, necrosis, redness in the right quadriceps at the site of injection, piloerection, unsteady state, and loss of motor function) were monitored daily after each i.m. administration until total disappearance of clinical signs. [0069] FIGURE 7 represents the design of mouse studies for in vivo and ex vivo bioimaging. Mice were injected once by i.m. route, in the right quadriceps, with 0.4µg of mRNA encoding Firefly Luciferase (FFLuc), encapsulated in OF-02 LNP, alone or with 50µg of SPA09. The in vivo expression of luciferase was assessed longitudinally by imaging the right quadriceps from the same five mice per group over 7 days (e.g. at 6 hours, 1 day, 2 days, 3 days and 7 days) post-injection. The ex vivo expression of luciferase was assessed by imaging the right quadriceps from five euthanized mice per group at 6 hours, 3 days and 7 days post- injection. [0070] FIGURE 8 represents the kinetics of FFLuc expression in vivo and ex vivo induced at the site of injection in mice (right quadriceps) of a 0.4µg-dose of mRNA encoding FFLuc in GL-HEPES-E3-E12-DS-4-E10 LNP, alone or with a 50µg-dose of SPA09. Corresponding design of mouse studies is shown in Figure 7. [0071] FIGURE 9 represents the design of mouse studies for analysis of proinflammatory cytokines and chemokines profile responses. Mice were injected twice 3 weeks apart by i.m. route in the right quadriceps with 0.1µg-dose of mRNA encoding HA-H3 Tasm in GL-HEPES-E3-E12-DS-4-E10 LNP, alone or with SPA09 (at a dose of 20µg or 50µg), or with 1.6 µg of the same mRNA in the same LNP, alone. Blood samples and right quadriceps were collected 4 hours, one day and 3 days following the second administration. [0072] FIGURES 10 A-G represent the proinflammatory cytokines and chemokines (A: G-CSF and GM-CSF, B: TNF^ and MIP-2^, C: RANTES and MCP-1, D: MIP-1^ and MIP-1^, E: GRO-^ and IL-1RA, F: IFN^, and G: IP-10) induced at the site of injection, following the second i.m. injection. Corresponding design of mouse studies is shown in Figure 9. Cytokines and chemokines concentrations were determined in crushed muscle using a multiplex array kit, or by ELISA (for IL-1RA). [0073] FIGURES 11 A-B: represent A: the MNA titers (top : RSV titers; bottom : hMPV titers) at day 35 induced in mice having received two i.m. injections of a combination of two mRNAs (1:1) encoding RSV and hMPV pre-F antigens, respectively, at various doses (0.2µg, 1µg or 5µg in total), co-encapsulated in GL-HEPES-E3-E12-DS-4-E10 LNP, alone or with 10µg, 25µg or 50µg of SPA09. Mice having received two i.m. injections of SPA09 only (50 µg) were used as a negative control group. *: p < 0.05. ***: p < 0.001. ns: not statistically significant; and B: in the same mice as in Figure 11A, edema was monitored at injection site for 3 days after each immunization. Results are shown post-dose 2. [0074] FIGURE 12 represents the HI antibody titers at day 35 induced in mice having received two i.m. injections (as described in Figure 2) of a 0.4µg-dose of mRNA encoding HA- H3 Tasm in GL-HEPES-E3-E12-DS-4-E10 LNP, alone or with a 20µg-dose of SPA09 or of PAA having a weight average molecular weight of 100KDa. *: represents the p < 0.05. [0075] FIGURE 13 represents the HI antibody titers at day 35 induced in mice having received two i.m. injections (as described in Figure 2) of a 0.1µg-dose or 0.4µg-dose of mRNA encoding HA-H3 Tasm encapsulated in a LNP with either ALC-0315, SM-102 or MC-3 as ionizable lipid, alone or with a 20µg-dose of SPA09. As a control, the HI antibody titer induced in mice having received 2 i.m. injections of a 0.4µg-dose of the same mRNA in GL-HEPES- E3-E12-DS-4-E10 LNP, without SPA09, is indicated. As a negative control, the HI antibody titer induced in mice having received only the dilution buffer is represented. **: p < 0.01. ***: p < 0.001. [0076] FIGURES 14 A-C illustrate the percentage of single cytokine-secreting and multiple cytokines secreting CD4+ T-cells, in mice having received two i.m. injections (as described in Figure 2) with 0.1µg-dose of mRNA encoding HA-H3 Tasm in GL-HEPES-E3- E12-DS-4-E10 LNP, alone or with SPA09 (at a dose of 20µg or 50µg), or with 1.6 µg of the same mRNA in the same LNP, alone. As negative control group, mice received two injections with buffer, 3 weeks apart. As positive control group, mice received 10µg of recombinant HA with 50µg/dose of SPA09, according to the same immunization schedule. Figure 14 A: percentage of CD4+ T cells secreting one of IFN-γ, IL-2 and TNF-α. Figure 14 B: percentage of CD4+ T cells secreting at least two of IFN-γ, IL-2 and TNF-α. Figure 14 C: summary of the respective percentages of CD4+ T cells secreting either one, two or three of the cytokines IFN- γ, IL-2 and TNF-α. The percentage of CD4+ T cells expressing at least IFN-γ is also illustrated. [DESCRIPTION OF THE SEQUENCES] [0077] SEQ ID NO: 1 represents a 5’UTR derived from CMV [0078] GGACAGAUCGCCUGGAGACGCCAUCCACGCUGUUUUGACCUCCAUAGA AGACACCGGGACCGAUCCAGCCUCCGCGGCCGGGAACGGUGCAUUGGAACGCGGAU UCCCCGUGCCAAGAGUGACUCACCGUCCUUGACACG [0079] SEQ ID NO: 2 represents a 3’ UTR derived from hGH [0080] CGGGUGGCAUCCCUGUGACCCCUCCCCAGUGCCUCUCCUGGCCCUGG AAGUUGCCACUCCAGUGCCCACCAGCCUUGUCCUAAUAAAAUUAAGUUGCAUC [0081] SEQ ID NO: 3 represents an RNA sequence encoding an hemagglutinin (HA) from influenza A/Tasmania/503/2020 (H3N2) [0082] AUGAAGACCAUCAUCGCUCUGUCCUACAUCCUGUGCCUGGUGUUUGCU CAGAAAAUCCCCGGGAAUGACAAUUCCACUGCCACUCUCUGCCUGGGCCAUCAUGCC GUGCCAAAUGGAACCAUUGUCAAGACUAUAACAAAUGACCGCAUCGAAGUGACCAAC GCUACCGAGCUGGUUCAGAACAGCAGUAUUGGAGAAAUCUGCGAUUCCCCACACCAG AUACUGGAUGGCGGCAACUGCACCCUGAUCGACGCACUGCUGGGUGACCCUCAGUG CGACGGAUUUCAGAAUAAGGAGUGGGACCUUUUCGUUGAGCGCAGCAGAGCCAAUA GCAACUGCUACCCGUACGACGUGCCGGAUUACGCCAGUCUUCGAAGCCUGGUCGCA UCCAGCGGGACACUGGAGUUUAAGAAUGAGUCCUUUAAUUGGACAGGCGUGAAGCA GAACGGGACUAGCAGCGCAUGCAUUCGGGGCAGUAGCUCAUCCUUCUUUAGCCGAC UGAACUGGCUGACCCACCUCAACUACACAUACCCCGCACUGAAUGUGACUAUGCCAA ACAAAGAACAGUUUGACAAACUGUACAUCUGGGGAGUGCACCAUCCUAGCACAGACA AGGACCAGAUCAGCCUGUUUGCCCAGCCCAGCGGCAGGAUUACCGUGUCCACAAAAC GGUCACAGCAAGCCGUGAUCCCUAAUAUUGGAUCCCGCCCCCGGAUAAGGGACAUCC CUAGUCGCAUCAGUAUCUACUGGACCAUCGUGAAGCCCGGAGAUAUCUUGCUCAUCA AUAGCACUGGCAACCUCAUUGCCCCCAGGGGCUAUUUUAAGAUCAGAAGCGGCAAGU CCAGCAUUAUGCGCAGCGACGCACCCAUUGGCAAGUGCAAGUCCGAGUGCAUCACUC CUAAUGGGUCCAUCCCAAACGACAAGCCAUUCCAAAAUGUCAACAGAAUCACCUACGG GGCUUGCCCCCGCUACGUGAAGCAGAGUACACUGAAACUGGCCACCGGGAUGCGCA ACGUGCCCGAGAAGCAAACUAGAGGCAUCUUUGGAGCUAUCGCUGGCUUCAUUGAGA AUGGCUGGGAGGGUAUGGUGGACGGCUGGUACGGAUUCCGCCACCAGAAUAGCGAA GGCAGAGGCCAGGCAGCAGACUUGAAGUCCACCCAGGCCGCCAUUGAUCAGAUCAAC GGCAAACUGAAUCGGCUUAUUGGAAAAACAAACGAGAAGUUCCAUCAGAUUGAGAAG GAGUUUAGCGAGGUGGAGGGCCGCGUGCAGGAUCUGGAAAAGUACGUUGAAGACAC CAAGAUCGACCUGUGGUCAUACAAUGCAGAGCUGCUCGUUGCCCUGGAAAAUCAGCA CACAAUUGACCUUACAGACUCCGAAAUGAAUAAGCUCUUUGAAAAGACCAAGAAGCAG CUGCGCGAGAACGCCGAGGAUAUGGGGAACGGUUGUUUUAAGAUCUACCACAAGUG UGACAACGCCUGCAUUGGGUCCAUCCGAAAUGAAACAUACGACCACAACGUGUAUAG AGAUGAGGCCCUGAACAACCGAUUCCAGAUUAAGGGAGUCGAGCUGAAGAGUGGCUA UAAGGACUGGAUCCUGUGGAUCUCAUUCGCCAUGUCAUGCUUCCUUCUGUGUAUUG CUCUGCUCGGCUUCAUCAUGUGGGCUUGCCAGAAAGGCAAUAUCCGGUGCAACAUC UGCAUCUAA [0083] SEQ ID NO: 4 represents an RNA sequence encoding firefly luciferase (FFLuc) [0084] AUGGAAGAUGCCAAAAACAUUAAGAAGGGCCCAGCGCCAUUCUACCCA CUCGAAGACGGGACCGCCGGCGAGCAGCUGCACAAAGCCAUGAAGCGCUACGCCCU GGUGCCCGGCACCAUCGCCUUUACCGACGCACAUAUCGAGGUGGACAUUACCUACG CCGAGUACUUCGAGAUGAGCGUUCGGCUGGCAGAAGCUAUGAAGCGCUAUGGGCUG AAUACAAACCAUCGGAUCGUGGUGUGCAGCGAGAAUAGCUUGCAGUUCUUCAUGCCC GUGUUGGGUGCCCUGUUCAUCGGUGUGGCUGUGGCCCCAGCUAACGACAUCUACAA CGAGCGCGAGCUGCUGAACAGCAUGGGCAUCAGCCAGCCCACCGUCGUAUUCGUGA GCAAGAAAGGGCUGCAAAAGAUCCUCAACGUGCAAAAGAAGCUACCGAUCAUACAAAA GAUCAUCAUCAUGGAUAGCAAGACCGACUACCAGGGCUUCCAAAGCAUGUACACCUU CGUGACUUCCCAUUUGCCACCCGGCUUCAACGAGUACGACUUCGUGCCCGAGAGCU UCGACCGGGACAAAACCAUCGCCCUGAUCAUGAACAGUAGUGGCAGUACCGGAUUGC CCAAGGGCGUAGCCCUACCGCACCGCACCGCUUGUGUCCGAUUCAGUCAUGCCCGC GACCCCAUCUUCGGCAACCAGAUCAUCCCCGACACCGCUAUCCUCAGCGUGGUGCCA UUUCACCACGGCUUCGGCAUGUUCACCACGCUGGGCUACUUGAUCUGCGGCUUUCG GGUCGUGCUCAUGUACCGCUUCGAGGAGGAGCUAUUCUUGCGCAGCUUGCAAGACU AUAAGAUUCAAUCUGCCCUGCUGGUGCCCACACUAUUUAGCUUCUUCGCUAAGAGCA CUCUCAUCGACAAGUACGACCUAAGCAACUUGCACGAGAUCGCCAGCGGCGGGGCG CCGCUCAGCAAGGAGGUAGGUGAGGCCGUGGCCAAACGCUUCCACCUACCAGGCAU CCGCCAGGGCUACGGCCUGACAGAAACAACCAGCGCCAUUCUGAUCACCCCCGAAGG GGACGACAAGCCUGGCGCAGUAGGCAAGGUGGUGCCCUUCUUCGAGGCUAAGGUGG UGGACUUGGACACCGGUAAGACACUGGGUGUGAACCAGCGCGGCGAGCUGUGCGUC CGUGGCCCCAUGAUCAUGAGCGGCUACGUUAACAACCCCGAGGCUACAAACGCUCUC AUCGACAAGGACGGCUGGCUGCACAGCGGCGACAUCGCCUACUGGGACGAGGACGA GCACUUCUUCAUCGUGGACCGGCUGAAGAGCCUGAUCAAAUACAAGGGCUACCAGGU AGCCCCAGCCGAACUGGAGAGCAUCCUGCUGCAACACCCCAACAUCUUCGACGCCGG GGUCGCCGGCCUGCCCGACGACGAUGCCGGCGAGCUGCCCGCCGCAGUCGUCGUG CUGGAACACGGUAAAACCAUGACCGAGAAGGAGAUCGUGGACUAUGUGGCCAGCCAG GUUACAACCGCCAAGAAGCUGCGCGGUGGUGUUGUGUUCGUGGACGAGGUGCCUAA AGGACUGACCGGCAAGUUGGACGCCCGCAAGAUCCGCGAGAUUCUCAUUAAGGCCAA GAAGGGCGGCAAGAUCGCCGUGUAA [0085] SEQ ID NO: 5 represents a poly(A) tail: [0086] AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGCAUAUGACUAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA [0087] SEQ ID NO: 6 represents a 5’UTR: [0088] GGGAUCCUACC [0089] SEQ ID NO: 7 represents an RNA sequence encoding an RSV pre-F protein [0090] AUGGAACUGCUGAUCCUCAAAGCCAACGCAAUCACCACCAUUCUCACC GCUGUGACCUUCUGCUUCGCAUCGGGGCAGAACAUCACUGAAGAGUUUUACCAGAG CACUUGCAGCGCGGUGUCAAAGGGUUACCUUUCCGCACUGCGGACCGGAUGGUACA CUUCCGUGAUCACCAUUGAGCUCAGCAACAUCAAGGAAAACAAGUGCAAUGGCACCG ACGCCAAGGUCAAGCUGAUCAAACAAGAACUGGACAAGUACAAGAACGCCGUGACAG AAUUGCAGCUCCUGAUGGGAUCCGGAAACGUCGGUCUGGGCGGAGCCAUCGCGAGU GGAGUGGCUGUGUCCAAGGUCUUGCACCUCGAGGGAGAAGUGAACAAGAUCAAGUC CGCGCUGCUGUCAACGAACAAGGCCGUGGUGUCCCUGUCUAACGGCGUCAGCGUGC UGACGUUCAAGGUCCUGGACCUGAAGAAUUACAUUGACAAGCAGCUGCUGCCCAUCC UCAACAAGCAAUCCUGCUCCAUCUCCAACCCCGAAACCGUGAUCGAGUUCCAGCAGA AGAACAACCGCCUGCUGGAAAUUACUCGCGAGUUCUCUGUGAAUGCCGGCGUGACCA CCCCUGUGUCCACCUACAUGCUGACCAACUCCGAGCUUCUCUCCCUUAUCAAUGACA UGCCUAUCACGAACGACCAGAAGAAGCUGAUGUCGAACAACGUGCAGAUUGUGCGGC AGCAGUCAUACAGCAUCAUGUCGAUCAUCAAGGAAGAAGUGCUGGCGUACGUGGUGC AACUCCCGCUGUACGGCGUCAUCGAUACCCCGUGCUGGAAGCUGCACACCUCGCCU UUGUGUACCACCAACACCAAGAACGGAUCCAACAUCUGCUUAACCCGGACUGAUCGG GGUUGGUACUGCGACAACGCCGGGAAUGUUUCGUUCUUCCCACAAGCCGAGACUUG UAAAGUGCAGUCAAACAGAGUGUUCUGUGACACCAUGAACUCGAGAACCCUGCCCAG CGAAGUGAACCUGUGUAACGUCGACAUCUUUAACCCAAAAUACGAUUGCAAGAUUAU GACCAGCAAAACCGACGUGUCCUCCUCCGUGAUAACAAGCCUGGGGGCGAUUGUGU CAUGCUACGGAAAGACUAAGUGCACCGCCUCGAACAAGAACCGCGGCAUCAUUAAGA CUUUCUCGAAUGGUUGCGACUAUGUGUCCAACAAGGGCGUGGAUACUGUGUCAGUC GGGAAUACUCUUUACUACGUGAACAAGCAGGAGGGGAAAAGCCUCUACGUGAAGGGA GAGCCUAUUAUCAACUUUUACGAUCCGCUGGUGUUCCCGUCCGACGAAUUCGACGCC AGCAUCAGCCAAGUCAACGAGCUGAUUAACCAGUCCCUCGCCUUCAUCAACCAAUCC GACGAGCUCCUGCAUAACGUGAACGCCGGAAAGUCCACCACCAACAUCAUGAUCACU ACUAUUAUCAUCGUGAUCAUCGUCAUCCUGCUGAGCCUGAUUGCUGUGGGCCUGUU GCUGUAUUGCAAAGCCAGGUCCACCCCGGUCACCCUGUCGAAGGAUCAGCUGUCCG GAAUCAACAACAUUGCCUUCUCCAACUAA [0091] SEQ ID NO: 8 represents an RNA sequence encoding an hMPV pre-F protein [0092] AUGAGCUGGAAGGUUGUGAUUAUUUUCUCUCUGCUGAUUACUCCACAG CACGGCCUGAAGGAGUCCUACCUGGAGGAGUCCUGUUCUACUAUCACUGAGGGGUA UCUCUCUGUGCUGCGGACAGGGUGGUAUACAGUGGUGUUCACCCUGGAGGUUGGCG AUGUGGAGAAUCUGACUUGCAGCGAUGGCCCUUCUCUGAUCAAGACCGAGCUGGAU CUGACAAAAAGCGCCCUCAGAGAACUGAAAACCGUGUCCGCCGAUCAGCUGGCAAGG GAGGAGCAGAUCGAGAACCCACGGCAGAGCAGGUUUGUGCUGGGCGCUAUCGCUCU GGGCGUGGCCACUGCAGCUGCUGUCACUGCAGGGGUCGCAAUCGCUAAGACUAUCA GACUGGAAUCCGAGGUGACCGCCAUUAAGAAUGCCCUGAAGACUACCAACGAGGCUG UGUCCACUCUGGGAAACGGAGUGAGGGUCCUGGCCUUCGCAGUGAGGGAGCUGAAG GAUUUUGUGUCAAAGAACCUUACACGGGCCAUCAACAAGAAUAAGUGCGAUAUCGAU GACCUGAAGAUGGCCGUGUCCUUCUCCCAGUUCAACCGGCGCUUUCUGAAUGUGGU GCGCCAGUUUUCCGACAACGCUGGAAUCACCCCUGCUAUCAGCCUGGACCUCAUGAC CGACGCCGAACUCGCAAGGGCCGUUUCUAACAUGCCUACAUCCGCUGGACAGAUUAA GCUGAUGCUGGAGAAUAGAGCAAUGGUGAGGAGAAAGGGAUUCGGCAUCCUGAUUG GCGUGUACGGAUCUAGCGUGAUCUACAUGGUGCAGCUGCCGAUCUUCGGCGUGAUC GAUACUCCUUGUUGGAUCGUCAAGGCCGCCCCUUCCUGCUCCGAGAAGAAGGGCAA UUACGCUUGUCUGCUGCGGGAGGACCAGGGCUGGUAUUGCCAGAACGCCGGGUCUA CAGUGUACUAUCCUAACGAGAAGGAUUGCGAGACCAGAGGCGACCACGUUUUCUGUG AUACAGCCGCCGGAAUCAAUGUCGCAGAGCAGUCUAAGGAGUGCAACAUCAAUAUCU CUACAACCAAUUACCCAUGUAAGGUGAGCACUGGACGGCACCCUAUCAGUAUGGUGG CUCUGAGCCCACUGGGGGCACUGGUGGCUUGCUACAAGGGGGUGAGCUGCAGUAUC GGCAGUAACAGAGUGGGCAUUAUCAAGCAGCUGAACAAAGGGUGCUCUUAUAUUACA AACCAGGAUGCAGAUACUGUGACCAUCGACAACACUGUGUACCAGCUGUCCAAGGUG GAGGGGGAGCAGCAUGUGAUCAAAGGGAGACCCGUCUCUUCUUCUUUCGAUCCCAU CAAGUUCCCUGAAGACCAGUUCAAUGUUGCCCUGGACCAGGUUUUCGAGAACAUCGA AAAUAGCCAGGCCUUGGUCGAUCAAUCCAACAGGAUCCUGAGCAGCGCAGAGAAAGG GAACACUGGCUUCAUCAUCGUGAUCAUUCUGAUCGCCGUGCUGGGGAGCAGUAUGA UUCUGGUGUCCAUUUUCAUCAUCAUCAAGAAGACCAAGAAGCCUACAGGAGCACCCC CUGAGCUGAGCGGAGUGACCAACAACGGCUUUAUCCCUCACAACUAA [DETAILED DESCRIPTION] Definitions [0093] Unless otherwise defined herein, scientific and technical terms used in connection with the present disclosure shall have the meanings that are commonly understood by those of ordinary skill in the art. For example, the Concise Dictionary of Biomedicine and Molecular Biology, Juo, Pei-Show, 2nd ed., 2002, CRC Press; The Dictionary of Cell and Molecular Biology, 3rd ed., 1999, Academic Press; and the Oxford Dictionary Of Biochemistry And Molecular Biology, Revised, 2000, Oxford University Press, may provide one of skill with a general dictionary of many of the terms used in this disclosure. Exemplary methods and materials are described below, although methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure. In case of conflict, the present specification, including definitions, will control. Generally, nomenclature used in connection with, and techniques of, cell and tissue culture, molecular biology, virology, immunology, microbiology, genetics, analytical chemistry, synthetic organic chemistry, medicinal and pharmaceutical chemistry, and protein and nucleic acid chemistry and hybridization described herein are those well-known and commonly used in the art. Enzymatic reactions and purification techniques are performed according to manufacturer’s specifications, as commonly accomplished in the art or as described herein. Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular. [0094] Units, prefixes, and symbols are denoted in their International Units System accepted form. Numeric ranges are inclusive of the numbers defining the range. Unless otherwise indicated, amino acid sequences are written left to right in amino to carboxy orientation. The headings provided herein are not limitations of the various aspects of the disclosure. Accordingly, the terms defined immediately below are more fully defined by reference to the specification in its entirety. [0095] Although a number of documents are cited herein, this citation does not constitute an admission that any of these documents forms part of the common general knowledge in the art. [0096] Have. Has. Having. Comprise(s). Comprising. Include(s). Including. Contain(s). Containing. Throughout this specification and embodiments, these terms and variations thereof will be understood to imply the inclusion of stated element(s), number(s), or step(s), without excluding any other element(s), number(s), or step(s). [0097] Throughout this specification and embodiments, a composition or method described as "comprising" one or more named elements or steps is open-ended, meaning that the named elements or steps are essential, but other elements or steps may be added within the scope of the composition or method. To avoid prolixity, it is also understood that any composition or method described as "comprising" (or which "comprises") one or more named elements or steps also describes the corresponding, more limited composition or method "consisting essentially of' (or which "consists essentially of') the same named elements or steps, meaning that the composition or method includes the named essential elements or steps and may also include additional elements or steps that do not materially affect the basic and novel characteristic(s) of the composition or method. It is also understood that any composition or method described herein as "comprising" or "consisting essentially of' one or more named elements or steps also describes the corresponding, more limited, and closed-ended composition or method "consisting of' (or "consists of') the named elements or steps to the exclusion of any other unnamed element or step. In any composition or method disclosed herein, known or disclosed equivalents of any named essential element or step may be substituted for that element or step. [0098] It is understood that wherever aspects are described herein with the language “comprising,” otherwise analogous aspects described in terms of “consisting of” and/or “consisting essentially of” are also provided. E.g. a composition “comprising” X may consist exclusively of X or may include something additional e.g. X + Y. [0099] A. An. Those terms used in connection with a given entity refer to one or more of that entity; for example, “a water-soluble polyanionic polymer” is understood to represent one or more water-soluble polyanionic polymer(s). As such, the terms “a” (or “an”), “one or more,” and “at least one” can be used interchangeably herein. [0100] About. Approximately. Those terms and variations thereof are used herein to mean approximately, roughly, around, or in the regions of. When the term “about” is used in conjunction with a numerical range, it modifies that range by extending the boundaries above and below the numerical values set forth. In general, the term “about” can modify a numerical value above and below the stated value by a variance of, e.g., 10 percent, up or down (higher or lower). In some embodiments, the term indicates deviation from the indicated numerical value by ±10%, ±5%, ±4%, ±3%, ±2%, ±1%, ±0.9%, ±0.8%, ±0.7%, ±0.6%, ±0.5%, ±0.4%, ±0.3%, ±0.2%, ±0.1%, ±0.05%, or ±0.01%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±10%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±5%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±4%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±3%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±2%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±1%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±0.9%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±0.8%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±0.7%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±0.6%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±0.5%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±0.4%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±0.3%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±0.1%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±0.05%. In some embodiments, “about” indicates deviation from the indicated numerical value by ±0.01%. [0101] Adjuvant. This term and variations thereof intend to refer to a substance which enhances the immune response against an antigen. The use of an adjuvant in an immunogenic or vaccine composition may allow to use lower doses of antigen (or of nucleic acid encoding the antigen) and/or to increase the immune responses induced, specific to the antigen. [0102] Administer. Administering. Those terms and variations thereof refer to delivering to a subject a composition as described herein. The composition can be administered to a subject using any methods known in the art. Those of ordinary skills in the art will be aware of a variety of routes that may, in appropriate circumstances, be utilized for administration to a subject, for example a human. For example, in some embodiments, administration may be parenteral, topical, oral, ocular etc. In some embodiments, the administration is parenteral administration. In some embodiments, the administration is an intramuscular administration. [0103] And/Or. This expression used herein is to be taken as specific disclosure of each of the two specified features or components with or without the other. Thus, the term “and/or” as used in a phrase such as “A and/or B” herein is intended to include “A and B,” “A or B,” “A” (alone), and “B” (alone). Likewise, the term “and/or” as used in a phrase such as “A, B, and/or C” is intended to encompass each of the following aspects: “A, B, and C”; “A, B, or C”; “A or C”; “A or B”; “B or C”; “A and C”; “A and B”; “B and C”; “A” (alone); “B” (alone); and “C” (alone). [0104] Antigen. This term and variations thereof intend to refer to a molecule, for example a peptide or a protein, which comprises at least one epitope against which an immune response is directed. Any suitable antigen may be envisioned which is a candidate for an immune response. An antigen may correspond to or may be derived from a naturally occurring antigen. Such naturally occurring antigens may include or may be derived from allergens, viruses, bacteria, fungi, parasites and other infectious agents and pathogens or an antigen may also be a tumor antigen. An antigen may be provided as a nucleic acid (e.g. mRNA) encoding such antigen. After administration to an individual, the nucleic acid may be translated into a peptide or protein able to elicit an immune response. [0105] Dose sparing. Nucleic acid dose sparing. mRNA dose sparing. Dose sparing of the antigen-encoding nucleic acid. As used herein, these expressions and variations thereof intend to refer to an effect induced by a compound or a formulation (e.g., an adjuvant) present in an immunogenic composition (e.g., a vaccine) and resulting in an immune response against a target antigen induced by the immunogenic composition containing a significantly lower dose or quantity of nucleic acid (e.g. mRNA) encoding the antigen compared to a similar immunogenic composition devoid of said compound or formulation and inducing an immune response of comparable or similar magnitude. A compound or formulation (e.g. an adjuvant) able to induce a dose sparing effect advantageously allows for the development of vaccines with lower production costs and potentially reduced reactogenicity, especially as such a compound or formulation allows to reduce the quantity of antigen-encoding nucleic acid present in an immunogenic composition. [0106] Cationic lipid. This expression and variations thereof intend to refer to a lipid species that exists in a positively charged form within a useful physiological range e.g., pH ~3 to pH ~9. Cationic lipids may be synthetic or naturally derived. [0107] Combination. This term and variations thereof intend to refer to a composition comprising two or more components, e.g., a water soluble polyanionic polymer and a nucleic acid carrier, wherein the components may be physically combined or mixed together in a single formulation, such that the components are administered simultaneously; or provided separately in individual formulations, wherein the components are intended to be administered concurrently or sequentially within a specified time frame. [0108] Composition. This term and variations thereof intend to refer to a discrete physical entity, in any form (e.g. gel, liquid, solid, gas) that comprises one or more specified components. [0109] Effective amount. As used herein, this expression and variations thereof refer to an amount (e.g., of a water-soluble polyanionic polymer, a nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, a nucleic acid encoding at least one antigen, or a composition as described herein) sufficient to effect beneficial or desired results. An effective amount can be administered in one or more administrations, applications or dosages, and is not intended to be limited to a particular formulation or administration route. The expression “effective amount” and variations thereof include, e.g., therapeutically effective amount and/or prophylactically effective amount. The term “effective amount” as used herein refers to an amount (e.g., of a nucleic acid, a polypeptide, a combination or a composition as described herein) which is effective for producing some desired therapeutic or prophylactic effects in the treatment or prevention of an infection, disease, disorder and/or condition at a reasonable benefit/risk ratio applicable to any medical treatment. [0110] Encapsulated. This term and variations thereof when used in relation with a nucleic acid and a nucleic acid carrier intend to refer to a nucleic acid surrounded and enclosed within the core structure of a nucleic acid carrier. A nucleic acid which is encapsulated in a nucleic acid carrier may be stably associated and protected by the nucleic acid carrier. This association may involve various mechanisms, such as physical entrapment, i.e., the nucleic acid is fully or partially surrounded by the nucleic acid carrier material, limiting its interaction with the external environment, or non-covalent interactions, i.e., the nucleic acid associates with the nucleic acid carrier through ionic interactions, hydrogen bonding, or hydrophobic interactions. Encapsulation shields the nucleic acid from degradation by enzymes (e.g., nucleases) present in biological fluids and facilitates its delivery into target cells. Nucleic acids are partially encapsulated when only a portion of the nucleic acids are encapsulated, for example at least 70%, or at least 75%, or at least 80% or at least 90% of the nucleic acids are encapsulated by the nucleic acid carrier. For instance, when the nucleic acid is an mRNA and the nucleic acid carrier is an LNP, encapsulation efficiency of the mRNA in the LNP, corresponding to the percentage of encapsulation, may be determined using the RIBOGREEN® assay, well-known to those of ordinary skill in the art. Briefly, the RIBOGREEN assay involves a step of lysis of the LNP with a detergent (e.g. Triton X-100) to liberate encapsulated mRNA, which can then interact with the RIBOGREEN fluorophore, and generate a fluorescent signal. Two separate measurements are performed (on untreated sample and on sample treated by the detergent) to determine the free and total mRNA content, respectively, which allows for the calculation of the proportion of encapsulated mRNA payload. A proportion of at least 70%, or at least 75%, or at least 80% or at least 90% of the mRNA encapsulated by the LNPs is generally accepted as a satisfying level of encapsulation, e.g. with respect to the expected protection effect mentioned above. [0111] Helper lipid. This expression and variations thereof intend to refer to a lipid molecule included in the formulation of a lipid nanoparticle (LNP), other than the main lipid component, to modulate the physicochemical properties of the LNP and improve its functionality. Helper lipids can perform various functions such as enhancing the stability of the LNP by reducing aggregation and improving colloidal properties, facilitating the fusion of the LNP with the target cell membrane, promoting intracellular delivery of the encapsulated cargo, aiding in the targeting of the lipid nanoparticle to specific cell types by incorporating ligands or targeting moieties, or modulating the release of the encapsulated cargo from the LNP within the target cell. Certain helper lipids can influence the responsiveness of the nanoparticle to specific stimuli (e.g., pH, enzymatic degradation), thereby controlling the release profile of the cargo. [0112] Immunogenic composition. This expression and variations thereof intend to refer to a composition comprising an antigen, an antigen-encoding nucleic acid or a precursor thereof, that, when administered to a subject, elicits an immune response, e.g. an antigen- specific immune response. The immune response may be a humoral (antibody) immune response and/or a cell-mediated immune response. The immunogenic composition of the disclosure may be a vaccine composition. [0113] Immune response. The expression "immune response" will be recognized and understood by the person of ordinary skill in the art, and is e.g. intended to refer to a specific reaction of the adaptive immune system to a particular antigen (so called specific or adaptive immune response) or an unspecific reaction of the innate immune system (so called unspecific or innate immune response), or a combination thereof. [0114] The expression "innate immune response" refers to the first line of defense of the innate immune system against pathogens. It provides a fast response to pathogens by many mechanisms, including inflammatory cytokine and chemokine production and complement activation. [0115] The expression "adaptive immune response" refers to an antigen-specific response of the immune system (the adaptive immune system). Antigen specificity allows for the generation of responses that are tailored to specific pathogens or pathogen-infected cells. The ability to mount these tailored responses is usually maintained in the body by "memory cells" (B-cells). [0116] Immunization method. This expression and variations thereof intend to refer to a medical intervention designed to induce a specific immune response against a target antigen in an individual in need thereof. An immunization method comprises at least a step of administering in an individual in need thereof an immunogenic composition in accordance with the disclosure, which can be administered to an individual who is susceptible to be infected by a pathogen expressing the target antigen for inducing an immune response against the pathogen or for boosting an immunity in an individual previously exposed to the pathogen or to an immune composition containing the target antigen. [0117] Immunogenicity. This term and variations thereof intend to refer to the capacity to elicit an immune response. [0118] Individual. Subject. Patient. Those terms and variations thereof are interchangeably used in the present disclosure and intends to refer to an organism, typically a mammal. Mammals include, but are not limited to, domesticated animals (e.g., cows, sheep, cats, dogs, and horses), primates (e.g., humans and non-human primates such as monkeys), rabbits, and rodents (e.g., mice and rats). In some embodiments, the individual is a human. [0119] Ionizable cationic lipid. This expression and variations thereof intend to refer to lipids containing one or more groups which can be protonated at physiological pH but may deprotonated at a pH above 8, 9, 10, 11, or 12. The ionizable cationic group may contain one or more protonatable amines which are able to form a cationic group at physiological pH. The ionizable cationic lipid compound may also further comprise one or more lipid components such as two or more fatty acids with C6-C24 alkyl or alkenyl carbon groups. These compounds may be a dendrimer, a dendron, a polymer, or a combination thereof. [0120] Kit-of-parts. This expression and variations thereof intend to refer to a packaged set of components in separate containers, such as one or more compounds or compositions possibly with one or more related materials such as solvents, solutions, buffers, or instructions. [0121] Lipid nanoparticle (LNP). This expression and variations thereof intend to refer to particles having at least one dimension on the order of nanometers (e.g., 1-1000 nm, or for example 10-800 nm, and for example from about 80 to about 200 nm as measured by Nanoparticle Tracking Analysis (NTA)). LNPs may comprise one or more of (i) at least one cationic or ionizable cationic lipid, (ii) a structural lipid, (iii) a stealth lipid and (iv) a helper lipid. LNPs can be included in a formulation that can be used to deliver a biologically active agent, such as a prophylactic agent or a therapeutic agent, to a target site of interest (e.g., cell, tissue, organ, tumor, and the like). [0122] mRNA. This term and variations thereof intend to refer to a single-stranded ribonucleic acid (RNA) molecule that carries genetic information from DNA. mRNA serves as a template for protein synthesis by ribosomes. An mRNA may be chemically modified to enhance stability, translation efficiency, or reduce reactogenicity. [0123] Neutral lipid. This expression and variations thereof intend to refer to any lipid components that is either not ionizable or is a neutral zwitterionic compound at a selected pH, for example at physiological pH. Such lipids include, but are not limited to, phosphatidylcholines, phosphatidylethanolamines sphingomyelins (SM), or neutral sphingolipids such as ceramides. Neutral lipids may be synthetic or naturally derived. [0124] Nucleic acid. Oligonucleotide. Polynucleotide. Those terms and variations thereof are used interchangeably to refer to polymeric forms of at least two nucleotides, either deoxyribonucleotides or ribonucleotides, or analogs thereof. A nucleic acid may have any three-dimensional structure, and may perform any function, known or unknown. [0125] A nucleic acid may be linear or cyclic. The following are non-limiting examples of nucleic acids: coding or non-coding regions of a gene or gene fragment, loci (locus) defined from linkage analysis, exons, introns, messenger RNA (mRNA), transfer RNA, ribosomal RNA, ribozymes, cDNA, closed-ended DNA (ceDNA), self-amplifying RNA (saRNA), stranded DNA (ssDNA), small interfering RNA (siRNA) and micro RNA (miRNA), recombinant polynucleotides, branched polynucleotides, plasmids, vectors, isolated DNA of any sequence, isolated RNA of any sequence, nucleic acid probes, and primers. [0126] In some embodiments, a nucleic acid is an isolated nucleic acid molecule or construct, e.g., messenger RNA (mRNA) or plasmid DNA (pDNA). The expression "isolated nucleic acid” and variations thereof intend to refer to a nucleic acid molecule, e.g., a segment of DNA or RNA, which has been removed from its native environment. Further examples of isolated nucleic acids include recombinant nucleic acids maintained in heterologous host cells or purified (partially or substantially) from other nucleic acids in a solution. Isolated RNA molecules include in vivo or in vitro gene transcripts. Isolated nucleic acids further include molecules produced synthetically. “Recombinant” as applied to a nucleic acid means that the nucleic acid is the product of various combinations of in vitro cloning, restriction and/or ligation steps, and other procedures that result in a construct that can potentially be expressed in a host cell. [0127] A nucleic acid can include regulatory elements such as promoters, enhancers, ribosome binding sites, or transcription termination signals. [0128] A nucleic acid may comprise modified nucleotides, such as methylated nucleotides and nucleotide analogs. If present, modifications to the nucleotide structure may be imparted before or after assembly of the polymer. The sequence of nucleic acids may be interrupted by non-nucleotide components. A nucleic acid may be further modified after polymerization, such as by conjugation with a labeling component. [0129] In some embodiments, a nucleic acid comprises a conventional phosphodiester bond. In some embodiments, a nucleic acid comprises a non-conventional bond (e.g., an amide bond, such as found in peptide nucleic acids (PNA)). [0130] The term “complement of a nucleic acid” denotes a nucleic acid molecule having a complementary base sequence and reverse orientation as compared to a reference sequence, such that it could hybridize with a reference sequence with complete fidelity. [0131] Nucleic acid carrier. This expression and variations thereof intend to refer to a molecule or a formulation that protects and facilitates the delivery and intracellular uptake of nucleic acids into target cells. The nucleic acid carrier comprises a core structure or moiety which functions to protect the nucleic acid and/or facilitate its delivery, e.g. by encapsulating the nucleic acid. The core structure can be formed from various materials, such as synthetic polymers (e.g., cationic polymers, polyethylene glycol), lipids (e.g., phospholipids, cholesterol), or inorganic materials (e.g., gold nanoparticles). [0132] Nucleic acid encoding an antigen. Antigen-encoding nucleic acid. These expressions and variations thereof intend to refer to a nucleic acid that contains the genetic information necessary for the production of an antigen. This nucleic acid comprises a coding region that translates into the amino acid sequence of the antigen, as well as optional regulatory sequences that influence the expression of the antigen. [0133] PEG-lipid. PEGylated lipid. These expressions and variations thereof are used interchangeably and intend to refer to a molecule comprising both a lipid portion and a polyethylene glycol portion. PEG-lipid are known in the art and include 1-(monomethoxy- polyethyleneglycol)-2,3-dimyristoylglycerol (PEG-DMG), and the like. [0134] Pharmaceutically acceptable salt. This expression and variations thereof intend to refer to salts of the compounds of the disclosure (e.g. water-soluble polyanionic polymers) which can be used in the formulation of an immunogenic composition, and which are physiologically acceptable, i.e., safe and effective for use in mammals (e.g. humans). A pharmaceutically acceptable salt may be suitable for parenteral administration, such as subcutaneous or intramuscular administration. [0135] Polymer. This term and variations thereof intend to refer to a molecule formed by the covalent linkage of numerous repeating units, derived from smaller molecules called monomers. These repeating units are connected together to create a long chain or network structure, which can be a linear, branched or crosslinked polymer. The repeating units may be identical (i.e., homopolymer) or different (i.e., copolymer or heteropolymer). [0136] Reactogenicity. This term and variations thereof intend to refer to a property to elicit a subset of reactions that occur after vaccination, as being a physical manifestation of the inflammatory response to vaccination, and can include injection-site pain, bruising, redness, swelling or induration at the injection site, as well as systemic symptoms, such as fever, myalgia, headache or rash. [0137] The broader term ‘safety’ profile refers to all adverse events (AEs) that could potentially be caused/triggered or worsened at any time after vaccination, and includes AEs, such as anaphylactic reactions, diseases diagnosed after vaccination and autoimmune events. [0138] Similar. Comparable. Those terms and variations thereof, when used to qualify the immune responses of different compositions, intend to refer to immune responses which achieve close overall outcome and/or share functional features. A close overall outcome refers to an overall outcome which is not statistically significantly different between the different compositions. Example 4 of the example section of the specification provides an illustration of a similar immunogenicity, provided by different compositions, i.e. immunogenicity not statistically significantly different, and also an illustration of immune responses which are not similar, i.e. which are statistically significantly different. [0139] Stealth lipid. This expression and variations thereof intend to refer to a lipid molecule, or a mixture of lipid molecules, that is chemically modified to reduce recognition and subsequent clearance by the mononuclear phagocyte system (MPS) after administration. The stealth lipid, when incorporated into a lipid nanoparticle, imparts prolonged circulation time within a mammal by reducing opsonization and phagocytosis by macrophages. A stealth lipid typically comprises a core structure derived from naturally occurring lipids, such as phospholipids, cholesterol or fatty acids, and a hydrophilic part containing hydrophilic polymers such as polyethylene glycol (PEG) (PEG-lipid), amino acids (e.g., sarcosine), or oxazolines, [0140] Sterol. Steroid alcohol. These expressions and variations thereof are used interchangeably and intend to refer to a group of lipids comprised of a sterane core bearing a hydroxyl moiety. As example of steroid alcohol, one may cite cholesterol, campesterol, sitosterol, stigmasterol and ergosterol. Esters of steroid alcohol or of sterol refer to ester of carboxylic acid with the hydroxyl group of the steroid alcohol. Suitable carboxylic acid comprises, further to the carboxyl moiety, a saturated or unsaturated, linear or branched, alkyl group. In some embodiments the alkyl group may be a C1-C20 alkyl group. In other embodiments, the carboxylic acid may be a fatty acid. [0141] Structural lipid. This expression and variations thereof intend to refer to a lipid molecule structuring the lipid bilayer shell of a lipid nanoparticle. Structural lipids provide stability, shape, and rigidity to the nanoparticle. Structural lipids can be naturally occurring or synthetic. A structural lipid may be a sterol. [0142] Water soluble polyanionic polymer. This expression and variations thereof intend to refer to a polymeric molecule that readily dissolves in aqueous solutions and possesses, at physiological pH (typically around pH 7.4), a net negative charge due to the presence of multiple anionic groups along its backbone or side chains. Common anionic groups include carboxylic acid (COOH) groups, sulfate (SO₃H) groups, or phosphate (PO₄H₂) groups. A polymer suitable for a composition of the disclosure is suitable for administration to an individual in need thereof. [0143] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. [0144] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure. All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. [0145] The list of sources, ingredients, and components as described hereinafter are listed such that combinations and mixtures thereof are also contemplated and within the scope herein. [0146] It should be understood that every maximum numerical limitation given throughout this specification includes every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this specification will include every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this specification will include every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein. [0147] All lists of items, such as, for example, lists of ingredients, are intended to and should be interpreted as Markush groups. Thus, all lists can be read and interpreted as items “selected from the group consisting of’ the list of items “and combinations and mixtures thereof.” [0148] Referenced herein may be trade names for components including various ingredients utilized in the present disclosure. The inventors herein do not intend to be limited by materials under any particular tradename. Equivalent materials (e.g., those obtained from a different source under a different name or reference number) to those referenced by tradename may be substituted and utilized in the descriptions herein. [0149] All publications and other references mentioned herein are incorporated by reference in their entirety. Although a number of documents are cited herein, this citation does not constitute an admission that any of these documents forms part of the common general knowledge in the art. Embodiments of the disclosure [0150] Embodiment 1, wherein the embodiment is a composition comprising: [0151] - at least one water-soluble polyanionic polymer, and [0152] - at least one nucleic acid carrier. [0153] Embodiment 2, wherein the embodiment is a composition comprising: [0154] - at least one water-soluble polyanionic polymer, and [0155] - at least one nucleic acid. [0156] Embodiment 3, wherein the embodiment is a composition comprising: [0157] - at least one water-soluble polyanionic polymer, [0158] - at least one nucleic acid carrier, and [0159] - at least one nucleic acid. [0160] Embodiment 4 according to embodiment 1, wherein the composition further comprises at least one nucleic acid. [0161] Embodiment 5 according to embodiment 2, wherein the composition further comprises at least one nucleic acid carrier. [0162] Embodiment 6 according to any one of embodiments 2-5, wherein the nucleic acid encodes at least one antigen. [0163] Embodiment 7 according to the preceding embodiment, wherein the composition is an immunogenic composition. [0164] Embodiment 8 according to any one of embodiments 6-7, wherein the water- soluble polyanionic polymer is an adjuvant. [0165] Embodiment 9 according to any one of embodiments 6-8, wherein the water- soluble polyanionic polymer is for adjuvanting the composition. [0166] Embodiment 10 according to any one of embodiments 6-9, wherein the water- soluble polyanionic polymer is an antigen-encoding nucleic acid dose-sparing agent. [0167] Embodiment 11 according to any one of embodiments 6-10, wherein the water- soluble polyanionic polymer is for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method. [0168] Embodiment 12 according to any one of embodiments 6-11, wherein the composition has an increased immunogenicity in comparison with a composition comprising a same nucleic acid and a same nucleic acid carrier and not comprising a water-soluble polyanionic polymer. [0169] Embodiment 13 according to any one of the preceding embodiments, wherein the water-soluble polyanionic polymer is a heteropolymer. [0170] Embodiment 14 according to any one of embodiments 1-12, wherein the water- soluble polyanionic polymer is a homopolymer. [0171] Embodiment 15 according to any one of the preceding embodiments, wherein the water-soluble polyanionic polymer is a non-crosslinked polymer. [0172] Embodiment 16 according to any one of the preceding embodiments, wherein the water-soluble polyanionic polymer is a linear polymer. [0173] Embodiment 17 according to any one of embodiments 1-15, wherein the water- soluble polyanionic polymer is a branched polymer. [0174] Embodiment 18 according to any one of embodiments 1-14, wherein the water- soluble polyanionic polymer is a crosslinked polymer. [0175] Embodiment 19 according to any one of the preceding embodiments, wherein the water-soluble polyanionic polymer comprises less than 0.005% w/w of free monomer, based on the total dry weight of the polymer. [0176] Embodiment 20 according to any one of the preceding embodiments, wherein the water-soluble polyanionic polymer is selected from a group consisting of polyacrylic acid polymer, polymethacrylic acid polymer, hyaluronic acid polymer, polyglutamic acid polymer, polyaspartic acid polymer, polystyrenesulfonic acid polymer, heparin polymer, dextran sulfate polymer, carboxymethyl cellulose polymer, alginic acid polymer, combinations thereof, and pharmaceutically acceptable salts thereof. [0177] Embodiment 21 according to any one of the preceding embodiments, wherein the water-soluble polyanionic polymer is selected from a group consisting of polyacrylic acid polymer, polymethacrylic acid polymer, hyaluronic acid polymer, polyaspartic acid polymer, polystyrenesulfonic acid polymer, heparin polymer, dextran sulfate polymer, carboxymethyl cellulose polymer, alginic acid polymer, combinations thereof, and pharmaceutically acceptable salts thereof. [0178] Embodiment 22 according to any one of preceding embodiments, wherein the water-soluble polyanionic polymer is a polyacrylic acid polymer or a pharmaceutically acceptable salt thereof. [0179] Embodiment 23 according to any one of preceding embodiments, wherein the water-soluble polyanionic polymer is exclusively composed of units corresponding to a salt of acrylic acid or is exclusively composed of units corresponding to the free acid form of acrylic acid and of units corresponding to a salt of acrylic acid. [0180] Embodiment 24 according to any one of preceding embodiments, wherein the water-soluble polyanionic polymer is a pharmaceutically acceptable salt of a polyacrylic acid polymer. [0181] Embodiment 25 according to any one of preceding embodiments, wherein the water-soluble polyanionic polymer is a sodium salt of a polyacrylic acid polymer. [0182] Embodiment 26 according to any one of preceding embodiments, wherein the water-soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 60 to about 650 kDa. [0183] Embodiment 27 according to any one of preceding embodiments, wherein the water-soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 80 to about 620 kDa, or in the range of about 80 to about 600 kDa. [0184] Embodiment 28 according to any one of preceding embodiments, wherein the water-soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 100 to about 600 kDa, or in the range of about 120 to about 600 kDa. [0185] Embodiment 29 according to any one of preceding embodiments, wherein the water-soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 100 to about 580 kDa, or in the range of about 150 to about 580 kDa. [0186] Embodiment 30 according to any one of preceding embodiments, wherein the water-soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 200 to about 540 kDa. [0187] Embodiment 31 according to any one of preceding embodiments, wherein the water-soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 250 to about 500 kDa. [0188] Embodiment 32 according to any one of preceding embodiments, wherein the water-soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 300 to about 400 kDa. [0189] Embodiment 33 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight Mw in the range of 350 to 650 kDa. [0190] Embodiment 34 according to any one of embodiments 1-26 and 33, wherein the water-soluble polyanionic polymer has a weight average molecular weight Mw in the range of 380 to 620 kDa. [0191] Embodiment 35 according to any one of embodiments 1-26 and 33-34, wherein the water-soluble polyanionic polymer has a weight average molecular weight Mw in the range of 400 to 600 kDa. [0192] Embodiment 36 according to any one of embodiments 1-26 and 33-35, wherein the water-soluble polyanionic polymer has a weight average molecular weight Mw in the range of 400 to 500 kDa. [0193] Embodiment 37 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) of about 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 2280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, or about 650 kDa. [0194] Embodiment 38 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) from about 60, or from about 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 2280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, or from about 640 to about 650 kDa. [0195] Embodiment 39 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) from about 60 to about 70, or to about 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 2280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640 or to about to 650 kDa. [0196] Embodiment 40 according to any one of the preceding embodiments, wherein the water-soluble polyanionic polymer has a polydispersity index below or equal to about 4, or below or equal to about 3.5, or below or equal to about 3, or below or equal to about 2.5. [0197] Embodiment 41 according to any one of the embodiments 1-39, wherein the water-soluble polyanionic polymer has a polydispersity index below or equal to about 4, 3.9, 3.8, 3.7, 3.6, 3.5, 3.4, 3.3, 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, or below or equal to about 2.5. [0198] Embodiment 42 according to any one of the embodiments 1-39, wherein the water-soluble polyanionic polymer has a polydispersity index from about 4.0, 3.9, 3.8, 3.7, 3.6, 3.5, 3.4, 3.3, 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, 2.5 to about 1.0. [0199] Embodiment 43 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 60 to about 650 kDa and a polydispersity index below or equal to 4. [0200] Embodiment 44 according to any one of embodiments 1-26, wherein the water-soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 80 to about 620 kDa and a polydispersity index below or equal to 4 or has a weight average molecular weight (Mw) in the range of about 80 to about 600 kDa and a polydispersity index below or equal to 4. [0201] Embodiment 45 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 100 to about 600 kDa and a polydispersity index below or equal to 4, or has a weight average molecular weight (Mw) in the range of about 120 to about 600 kDa and a polydispersity index below or equal to 4. [0202] Embodiment 46 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 100 to about 580 kDa and a polydispersity index below or equal to 4, or has a weight average molecular weight (Mw) in the range of about 150 to about 580 kDa and a polydispersity index below or equal to 4. [0203] Embodiment 47 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 200 to about 540 kDa and a polydispersity index below or equal to 4. [0204] Embodiment 48 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 250 to about 500 kDa and a polydispersity index below or equal to 4. [0205] Embodiment 49 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 300 to about 400 kDa and a polydispersity index below or equal to 4. [0206] Embodiment 50 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 60 to about 650 kDa and a polydispersity index below or equal to 2.5. [0207] Embodiment 51 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 80 to about 620 kDa and a polydispersity index below or equal to 2.5, or has a weight average molecular weight (Mw) in the range of about 80 to about 600 kDa and a polydispersity index below or equal to 2.5. [0208] Embodiment 52 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 100 to about 600 kDa and a polydispersity index below or equal to 2.5, or has a weight average molecular weight (Mw) in the range of about 120 to about 600 kDa and a polydispersity index below or equal to 2.5. [0209] Embodiment 53 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 100 to about 580 kDa and a polydispersity index below or equal to 2.5 or has a weight average molecular weight (Mw) in the range of about 150 to about 580 kDa and a polydispersity index below or equal to 2.5. [0210] Embodiment 54 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 200 to about 540 kDa and a polydispersity index below or equal to 2.5. [0211] Embodiment 55 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 250 to about 500 kDa and a polydispersity index below or equal to 2.5. [0212] Embodiment 56 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 300 to about 400 kDa and a polydispersity index below or equal to 2.5. [0213] Embodiment 57 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 60 to about 650 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0214] Embodiment 58 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 80 to about 620 kDa and a polydispersity index in the range of about 1.6 to about 2.5, or has a weight average molecular weight (Mw) in the range of about 80 to about 600 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0215] Embodiment 59 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 100 to about 600 kDa and a polydispersity index in the range of about 1.6 to about 2.5 or has a weight average molecular weight (Mw) in the range of about 120 to about 600 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0216] Embodiment 60 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 100 to about 580 kDa and a polydispersity index in the range of about 1.6 to about 2.5 or has a weight average molecular weight (Mw) in the range of about 150 to about 580 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0217] Embodiment 61 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 200 to about 540 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0218] Embodiment 62 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 250 to about 500 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0219] Embodiment 63 according to any one of embodiments 1-26, wherein the water- soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of about 300 to about 400 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0220] Embodiment 64 according to any one of embodiments 1-26, wherein the polymer has a weight average molecular weight Mw in the range of 350 to 650 kDa and a polydispersity index below or equal to 4. [0221] Embodiment 65 according to any one of embodiments 1-26, wherein the polymer has a weight average molecular weight Mw in the range of 380 to 620 kDa and a polydispersity index below or equal to 4. [0222] Embodiment 66 according to any one of embodiments 1-26, wherein the polymer has a weight average molecular weight Mw in the range of 400 to 600 kDa and a polydispersity index below or equal to 4. [0223] Embodiment 67 according to any one of embodiments 1-26, wherein the polymer has a weight average molecular weight Mw in the range of 350 to 650 kDa and a polydispersity index below or equal to 2.5. [0224] Embodiment 68 according to any one of embodiments 1-26, wherein the polymer has a weight average molecular weight Mw in the range of 380 to 620 kDa and a polydispersity index below or equal to 2.5. [0225] Embodiment 69 according to any one of embodiments 1-26, wherein the polymer has a weight average molecular weight Mw in the range of 400 to 600 kDa and a polydispersity index below or equal to 2.5. [0226] Embodiment 70 according to any one of preceding embodiments, wherein the water-soluble polyanionic polymer has a Mark Houwink slope higher or equal to 0.7. [0227] Embodiment 71 according to any one of embodiments 3-70, wherein the nucleic acid is complexed with and/or at least partially encapsulated in the nucleic acid carrier. [0228] Embodiment 72 according to embodiment 71, wherein at least 70% of the nucleic acid is encapsulated in the nucleic acid carrier. [0229] Embodiment 73 according to embodiment 71, wherein at least 75% of the nucleic acid is encapsulated in the nucleic acid carrier. [0230] Embodiment 74 according to embodiment 71, wherein at least 80% of the nucleic acid is encapsulated in the nucleic acid carrier. [0231] Embodiment 75 according to embodiment 71, wherein at least 90% of the nucleic acid is encapsulated in the nucleic acid carrier. [0232] Embodiment 76 according to any one of embodiments 3-75, wherein the composition is obtainable by a process comprising at least the steps of: [0233] (a) formulating at least one nucleic acid, e.g. wherein the at least one nucleic acid encodes at least one antigen, with at least one nucleic acid carrier, thus obtaining a first composition, and [0234] (b) formulating the first composition obtained in step (a) with at least one water- soluble polyanionic polymer to obtain a composition of the disclosure. [0235] Embodiment 77 according to embodiment 76, wherein further to step (a), the nucleic acid is complexed with and/or at least partially encapsulated in the nucleic acid carrier. [0236] Embodiment 78 according to embodiment 76 or 77, wherein step b) is carried out by gently mixing the first composition obtained in step (a) with the water-soluble polyanionic polymer. [0237] Embodiment 79 according to any one of embodiments 1, 3-78, wherein the nucleic acid carrier is a non-viral nucleic acid carrier. [0238] Embodiment 80 according to any one of embodiments 1, 3-79, wherein the nucleic acid carrier is selected in the group consisting of: lipid nanoparticles (LNP), solid lipid nanoparticles (SLNs), cationic nanoemulsions (CNEs), lipoplexes, cationic polymeric nanoparticles, immunostimulating complexes (ISCOMS), nanogels, inorganic nanoparticles, and lipidoid-coated iron oxide nanoparticles (LIONs). [0239] Embodiment 81 according to any one of embodiments 1, 3-80, wherein the nucleic acid carrier is a CNE. [0240] Embodiment 82 according to any one of embodiments 1, 3-80, wherein the nucleic acid carrier is a LION. [0241] Embodiment 83 according to any one of embodiments 1, 3-80, wherein the nucleic acid carrier is an LNP. [0242] Embodiment 84 according to any one of embodiments 1, 3-80 and 83, wherein the nucleic acid carrier comprises at least one cationic, or ionizable cationic, lipid. [0243] Embodiment 85 according to any one of embodiments 1, 3-80, 83 and 84, wherein the nucleic acid carrier comprises at least one stealth lipid. [0244] Embodiment 86 according to any one of embodiments 1, 3-80 and 83-85, wherein the nucleic acid carrier comprises at least one structural lipid. [0245] Embodiment 87 according to any one of embodiments 1, 3-80 and 83-86, wherein the nucleic acid carrier comprises at least one helper lipid. [0246] Embodiment 88 according to any one of embodiments 1, 3-80 and 83-87, wherein the nucleic acid carrier is an LNP, said LNP comprising, at least one cationic, or ionizable cationic, lipid, at least one stealth lipid, at least one structural lipid, and at least one helper lipid. [0247] Embodiment 89 according to any one of embodiments 84-88, wherein the cationic, or ionizable cationic, lipid is biodegradable. [0248] Embodiment 90 according to any one of embodiments 84-88, wherein the cationic, or ionizable cationic, lipid is not biodegradable. [0249] Embodiment 91 according to any one of embodiments 84-90, wherein the cationic, or ionizable cationic, lipid is cleavable. [0250] Embodiment 92 according to any one of embodiments 84-90, wherein the cationic, or ionizable cationic, lipid is not cleavable. [0251] Embodiment 93 according to any one of embodiments 84-92, wherein the cationic, or ionizable cationic, lipid is selected in the group consisting of: 2,5-piperazinedione based lipids, dianhydrohexitol based lipids, 2-(4-(alkyldisulfaneyl)alkyl)piperazine-1-yl)alkyl alkanoate based lipids, (hydroxyalkyl) disubstituted amine based lipids, and benzene-1,3,5- tricarboxamide based lipids. [0252] Embodiment 94 according to any one of embodiments 84-93, wherein the cationic, or ionizable cationic, lipid is selected from the group consisting of: cKK-E10; OF-02; [(6Z,9Z,28Z,31Z)-heptatriaconta-6,9,28,31-tetraen-19-yl] 4-(dimethylamino)butanoate (D-Lin- MC3-DMA or MC3); 2,2-dilinoleyl-4-dimethylaminoethyl-[1,3]-dioxolane (dLin-KC2-DMA); 1,2- dilinoleyloxy-N,N-dimethyl-3-aminopropane (dLin-DMA); di((Z)-non-2-en-1-yl) 9-((4- (dimethylamino)butanoyl)oxy)heptadecanedioate (L319); 9-heptadecanyl 8-{(2- hydroxyethyl)[6-oxo-6-(undecyloxy)hexyl]amino}octanoate (SM-102); [(4- hydroxybutyl)azanediyl]di(hexane-6,1-diyl) bis(2-hexyldecanoate) (ALC-0315); [3- (dimethylamino)-2-[(Z)-octadec-9-enoyl]oxypropyl] (Z)-octadec-9-enoate (DODAP); 2,5-bis(3- aminopropylamino)-N-[2-[di(heptadecyl)amino]-2-oxoethyl]pentanamide (DOGS); [(3S,8S,9S,10R,13R,14S,17R)-10,13-dimethyl-17-[(2R)-6-methylheptan-2-yl]- 2,3,4,7,8,9,11,12,14,15,16,17-dodecahydro-1H-cyclopenta[a]phenanthren-3-yl] N-[2- (dimethylamino)ethyl]carbamate (DC-Chol); tetrakis(8-methylnonyl) 3,3′,3″,3‴- (((methylazanediyl) bis(propane-3,1 diyl))bis (azanetriyl))tetrapropionate (306Oi10); decyl (2- (dioctylammonio)ethyl) phosphate (9A1P9); ethyl 5,5-di((Z)-heptadec-8-en-1-yl)-1-(3- (pyrrolidin-1-yl)propyl)-2,5-dihydro-1H-imidazole-2-carboxylate (A2-Iso5-2DC18); bis(2- (dodecyldisulfanyl)ethyl) 3,3′-((3-methyl-9-oxo-10-oxa-13,14-dithia-3,6- diazahexacosyl)azanediyl)dipropionate (BAME-O16B); 1,1′-((2-(4-(2-((2-(bis(2- hydroxydodecyl)amino)ethyl) (2-hydroxydodecyl)amino)ethyl) piperazin-1-yl)ethyl)azanediyl) bis(dodecan-2-ol) (C12-200); 3,6-bis(4-(bis(2-hydroxydodecyl)amino)butyl)piperazine-2,5- dione (cKK-E12); hexa(octan-3-yl) 9,9′,9″,9‴,9″″,9‴″- ((((benzene-1,3,5- tricarbonyl)yris(azanediyl)) tris (propane-3,1-diyl)) tris(azanetriyl))hexanonanoate (FTT5); (((3,6-dioxopiperazine-2,5-diyl)bis(butane-4, 1-diyl))bis(azanetriyl))tetrakis(ethane-2,1-diyl) (9Z,9′Z,9″Z,9‴Z,12Z,12′Z,12″Z,12‴Z)-tetrakis (octadeca-9,12-dienoate) (OF-Deg-Lin); TT3; N1,N3,N5-tris(3-(didodecylamino)propyl)benzene-1,3,5-tricarboxamide; N1-[2-((1S)-1- [(3-aminopropyl)amino]-4-[di(3-aminopropyl)amino]butylcarboxamido)ethyl]-3,4-di[oleyloxy]- benzamide (MVL5); heptadecan-9-yl 8-((2-hydroxyethyl)(8-(nonyloxy)-8- oxooctyl)amino)octanoate (Lipid 5); GL-HEPES-E3-E10-DS-3-E18-1; GL-HEPES-E3-E12- DS-4-E10; GL-HEPES-E3-E12-DS-3-E14; cOrn-EE1; MC3; IM-001; IS-001; and combinations thereof. [0253] Embodiment 95 according to any one of embodiments 84-94, wherein the cationic, or ionizable cationic, lipid is selected from the group consisting of: OF-02, cKK-E10, GL-HEPES-E3-E10-DS-3-E18-1, GL-HEPES-E3-E12-DS-4-E10, GL-HEPES-E3-E12-DS-3- E14, IM-001, IS-001, ALC-0315, SM-102, MC3, and combinations thereof, e.g. GL-HEPES- E3-E12-DS-4-E10. [0254] Embodiment 96 according to any one of embodiments 85-95, wherein the stealth lipid is a PEGylated lipid. [0255] Embodiment 97 according to the preceding embodiment, wherein the PEGylated lipid is a polyethylene glycol (PEG) chain of up to 5 kDa in length covalently attached to a lipid with alkyl chain(s) of C₆-C₂₀. [0256] Embodiment 98 according to embodiment 96 or 97, wherein the PEGylated lipid is selected from the group consisting of: 1,2-dimyristoyl-rac-glycero-3- methoxypolyethylene glycol (DMG-PEG); 1,2-distearoyl-sn-glycero-3-phosphoethanolamine- polyethylene glycol (DSPE-PEG); 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine- polyethylene glycol (DLPE-PEG); or 1,2-distearoyl-rac-glycero-polyethelene glycol (DSG- PEG), PEG-DAG; PEG-PE; PEG-S-DAG; PEG-S-DMG; PEG-cer; a PEG- dialkyoxypropylcarbamate; 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide (ALC- 0159); and combinations thereof. [0257] Embodiment 99 according to any one of embodiments 96-98, wherein the PEGylated lipid comprises a PEG of a molecular weight in the range of about 2000 to about 2400 g/mol. [0258] Embodiment 100 according to any one of embodiments 96-99, wherein the PEGylated lipid comprises a PEG being PEG2000 (or PEG-2K). [0259] Embodiment 101 according to any one of embodiments 96-100, wherein the PEGylated lipid is selected from the group consisting of: DMG-PEG2000, DSPE-PEG2000, DLPE-PEG2000, DSG-PEG2000, C8 PEG2000, ALC-0159 (2-[(polyethylene glycol)-2000]- N,N-ditetradecylacetamide), and combinations thereof. [0260] Embodiment 102 according to any one of embodiments 96-101, wherein the PEGylated lipid is DMG-PEG2000. [0261] Embodiment 103 according to any one of embodiments 96-101, wherein the PEGylated lipid is ALC-0159. [0262] Embodiment 104 according to any one of embodiments 86-103, wherein the structural lipid is a cholesterol-based lipid. [0263] Embodiment 105 according to the preceding embodiment, wherein the cholesterol-based lipid is selected from the group consisting of: DC-Choi (N,N-dimethyl-N- ethylcarboxamidocholesterol), l,4-bis(3-N-oleylamino-propyl)piperazine, imidazole cholesterol ester, sitosterol (22,23-dihydrostigmasterol), β-sitosterol, sitostanol, fucosterol, stigmasterol (stigmasta-5,22-dien-3-ol), ergosterol; desmosterol (3ß-hydroxy-5,24-cholestadiene); lanosterol (8,24-lanostadien-3b-ol); 7-dehydrocholesterol (Δ5,7-cholesterol); dihydrolanosterol (24,25-dihydrolanosterol); zymosterol (5α-cholesta-8,24-dien-3ß-ol); lathosterol (5α-cholest-7- en-3ß-ol); diosgenin ((3β,25R)-spirost-5-en-3-ol); campesterol (campest-5-en-3ß-ol); campestanol (5a-campestan-3b-ol); 24-methylene cholesterol (5,24(28)-cholestadien-24- methylen-3ß-ol); cholesteryl margarate (cholest-5-en-3ß-yl heptadecanoate); cholesteryl oleate; cholesteryl stearate; and combinations thereof. [0264] Embodiment 106 according to embodiment 104 or 105, wherein the cholesterol-based lipid is cholesterol. [0265] Embodiment 107 according to any one of embodiments 87-106, wherein the helper lipid is selected from the group consisting of: 1,2-dioleoyl-SN-glycero-3- phosphoethanolamine (DOPE); 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC); 1,2- dioleoyl-sn-glycero-3-phospho-L-serine (DOPS); 1,2-dielaidoyl-sn-glycero-3- phosphoethanolamine (DEPE); and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DPOC), dipalmitoylphosphatidylcholine (DPPC), DMPC, 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC), 1,2-Distearoylphosphatidylethanolamine (DSPE), and 1,2-dilauroyl-sn-glycero-3- phosphoethanolamine (DLPE), dioleoylphosphatidylcholine (DOPC), dioleoylphosphatidylglycerol (DOPG), dipalmitoylphosphatidylglycerol (DPPG), palmitoyloleoylphosphatidylcholine (POPC), palmitoyloleoyl-phosphatidylethanolamine (POPE), dioleoyl-phosphatidylethanolamine 4-(N-maleimidomethyl)-cyclohexane-l- carboxylate (DOPE-mal), dipalmitoyl phosphatidyl ethanolamine (DPPE), dimyristoylphosphoethanolamine (DMPE), phosphatidylserine, sphingolipids, sphingomyelins, ceramides, cerebrosides, gangliosides, 16-O-monomethyl PE, 16-O-dimethyl PE, 18-1-trans PE, l-stearoyl-2-oleoyl-phosphatidyethanolamine (SOPE), and combinations thereof. [0266] Embodiment 108 according to any one of embodiments 87-107, wherein the helper lipid is DOPE. [0267] Embodiment 109 according to any one of embodiments 87-107, wherein the helper lipid is DSPC. [0268] Embodiment 110 according to any one of embodiments 87-107, wherein the helper lipid is DEPE. [0269] Embodiment 111 according to any one of embodiments 1, 3-80 and 83-110, wherein the nucleic acid carrier is an LNP, said LNP comprising at least one cationic, or ionizable cationic, lipid, at least one stealth lipid, at least one structural lipid, and at least one helper lipid, wherein: [0270] - the cationic, or ionizable cationic, lipid is selected from the group consisting of OF-02, cKK-E10, GL-HEPES-E3-E10-DS-3-E18-1, GL-HEPES-E3-E12-DS-4-E10, GL- HEPES-E3-E12-DS-3-E14, IM-001, IS-001, ALC-0315, SM-102, MC3, and combinations thereof; [0271] - the stealth lipid is a PEGylated lipid, said PEGylated lipid comprising a PEG moiety being PEG2000 (or PEG-2K); [0272] - the structural lipid is cholesterol; and [0273] - the helper lipid is selected from the group consisting of 1,2-dioleoyl-SN- glycero-3-phosphoethanolamine (DOPE), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dielaidoyl-sn-glycero-3-phosphoethanolamine (DEPE), and combinations thereof. [0274] Embodiment 112 according to the preceding embodiment, wherein the PEGylated lipid is DMG-PEG2000 or ALC-0159. [0275] Embodiment 113 according to any one of embodiments 1, 3-80 and 83-112, wherein the nucleic acid carrier is an LNP, said LNP comprising at least one cationic, or ionizable cationic, lipid, at least one stealth lipid, at least one structural lipid, and at least one helper lipid, wherein (i) the cationic, or ionizable cationic, lipid is selected from OF-02, cKK- E10, GL-HEPES-E3-E10-DS-3-E18-1, GL-HEPES-E3-E12-DS-4-E10, GL-HEPES-E3-E12- DS-3-E14, IM-001 or IS-001; (ii) the stealth lipid is DMG-PEG2000; (iii) the structural lipid is cholesterol; and (iv) the helper lipid is DOPE. [0276] Embodiment 114 according to any one of embodiments 1, 3-80, 83-102, 104- 107, 109, and 111-112, wherein the nucleic acid carrier is an LNP, said LNP comprising (i) SM-102; (ii) DMG-PEG2000; (iii) cholesterol; and (iv) DSPC. [0277] Embodiment 115 according to any one of embodiments 1, 3-80, 83-101, 103- 107, 109, and 111-112, wherein the nucleic acid carrier is an LNP, said LNP comprising (i) ALC-0315; (ii) ALC-0159; (iii) cholesterol; and (iv) DSPC. [0278] Embodiment 116 according to any one of embodiments 1, 3-80 and 83-115, wherein the nucleic acid carrier is an LNP, said LNP comprising: [0279] a cationic, or ionizable cationic, lipid at a molar ratio of 35% to 55% or 40% to 50%, or at a molar ratio of 35%, 36%, 37%, 38%, 39%, 40%, 41% 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, or 55%; [0280] a stealth lipid at a molar ratio of 0.25% to 2.75% or 1.00% to 2.00% or at a molar ratio of 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.50%, 1.75%, 2.00%, 2.25%, 2.50%, or 2.75%; [0281] a structural lipid at a molar ratio of 20% to 50%, 25% to 45%, or 28.5% to 43% or at a molar ratio of 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41% 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%; and [0282] a helper lipid at a molar ratio of 5% to 35%, 8% to 30%, or 10% to 30% or at a molar ratio of 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, or 35%, [0283] wherein all of the molar ratios are relative to the total lipid content of the LNP. [0284] Embodiment 117 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: a cationic, or ionizable cationic, lipid at a molar ratio of 40%; a stealth lipid at a molar ratio of 1.5%; a structural lipid at a molar ratio of 28.5%; and a helper lipid at a molar ratio of 30%. [0285] Embodiment 118 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: a cationic, or ionizable cationic, lipid at a molar ratio of 45 to 50%; a stealth lipid at a molar ratio of 1.5 to 1.7%; a structural lipid at a molar ratio of 38 to 43%; and a helper lipid at a molar ratio of 9 to 10%. [0286] Embodiment 119 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: OF-02 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [0287] Embodiment 120 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: cKK-E10 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [0288] Embodiment 121 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: GL-HEPES-E3-E10-DS-3- E18-1 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [0289] Embodiment 122 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: GL-HEPES-E3-E12-DS-4- E10 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [0290] Embodiment 123 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: GL-HEPES-E3-E12-DS-3- E14 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [0291] Embodiment 124 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: IS-001 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [0292] Embodiment 125 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: IM-001 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [0293] Embodiment 126 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: SM-102 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DSPC at a molar ratio of 5% to 35%. [0294] Embodiment 127 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: ALC-0315 at a molar ratio of 35% to 55%; ALC-0159 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DSPC at a molar ratio of 5% to 35%. [0295] Embodiment 128 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: OF-02 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [0296] Embodiment 129 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: cKK-E10 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [0297] Embodiment 130 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: GL-HEPES-E3-E10-DS-3- E18-1 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [0298] Embodiment 131 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: GL-HEPES-E3-E12-DS-4- E10 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [0299] Embodiment 132 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: GL-HEPES-E3-E12-DS-3- E14 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [0300] Embodiment 133 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: IM-001 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [0301] Embodiment 134 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: IS-001 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [0302] Embodiment 135 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: 9-heptadecanyl 8-{(2- hydroxyethyl)[6-oxo-6-(undecyloxy)hexyl]amino}octanoate (SM-102) at a molar ratio of 50%; 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) at a molar ratio of 10%; cholesterol at a molar ratio of 38.5%; and 1,2-dimyristoyl-rac-glycero-3-methoxypolyethylene glycol-2000 (DMG-PEG2000) at a molar ratio of 1.5%. [0303] Embodiment 136 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: [(6Z,9Z,28Z,31Z)- heptatriaconta-6,9,28,31-tetraen-19-yl] 4-(dimethylamino)butanoate (MC3) at a molar ratio of 50%; 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) at a molar ratio of 10%; cholesterol at a molar ratio of 38.5%; and 1,2-dimyristoyl-rac-glycero-3-methoxypolyethylene glycol-2000 (DMG-PEG2000) at a molar ratio of 1.5%. [0304] Embodiment 137 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: (4- hydroxybutyl)azanediyl]di(hexane-6,1-diyl) bis(2-hexyldecanoate) (ALC-0315) at a molar ratio of 46.3%; 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) at a molar ratio of 9.4%; cholesterol at a molar ratio of 42.7%; and 2-[(polyethylene glycol)-2000]-N,N- ditetradecylacetamide (ALC-0159) at a molar ratio of 1.6%. [0305] Embodiment 138 according to any one of embodiments 1, 3-80 and 83-116, wherein the nucleic acid carrier is an LNP, said LNP comprising: (4- hydroxybutyl)azanediyl]di(hexane-6,1-diyl) bis(2-hexyldecanoate) (ALC-0315) at a molar ratio of 47.4%; 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) at a molar ratio of 10%; cholesterol at a molar ratio of 40.9%; and 2-[(polyethylene glycol)-2000]-N,N- ditetradecylacetamide (ALC-0159) at a molar ratio of 1.7%. [0306] Embodiment 139 according to any one of embodiments 1, 3-80 and 83-138, wherein the nucleic acid carrier is an LNP, said LNP having a mean diameter size of less than 150 nm, or less than 120 nm, or less than 100 nm, or less than 90 nm. [0307] Embodiment 140 according to any one of embodiments 2-80 and 83-139, wherein the nucleic acid is an RNA or a DNA. [0308] Embodiment 141 according to any one of embodiments 2-80 and 83-140, wherein the nucleic acid is selected from the group consisting of: double stranded RNA (dsRNA); single stranded RNA (ssRNA); double stranded DNA (dsDNA); single stranded DNA (ssDNA); and combinations thereof. [0309] Embodiment 142 according to any one of embodiments 2-80 and 83-141, wherein the nucleic acid is selected from the group consisting of: messenger RNA (mRNA); short interference RNA (siRNA): self-amplifying RNA (saRNA); micro RNA (miRNA); small nuclear RNA (snRNA); small nucleolar RNA (snoRNA); transfer RNA (tRNA): ribosomal RNA (rRNA): mitochondrial RNA (mtRNA): short hairpin RNA (shRNA): transfer-messenger RNA (tmRNA): viral RNA (vRNA): RNA (bpRNA): blunt-ended RNA; antisense oligonucleotide (ASO); plasmid DNA (pDNA); closed-ended DNA (ceDNA); and combinations thereof. [0310] Embodiment 143 according to any one of embodiments 140-142, wherein the RNA is an mRNA. [0311] Embodiment 144 according to any one of embodiments 140-143, wherein the RNA comprises at least one of a 5’ cap, a 5’ untranslated region (UTR), a 3’ UTR, a polyA tail. [0312] Embodiment 145 according to any one of embodiments 140-144, wherein the RNA comprises a 5’ cap, a 5’ UTR, a 3’ UTR and a polyA tail. [0313] Embodiment 146 according to any one of embodiments 140-145 wherein the RNA is an mRNA comprising an open reading frame (ORF) encoding an antigen. [0314] Embodiment 147 according to the preceding embodiment, wherein the antigen is derived from bacteria, viruses or parasites; e.g. the antigen is selected from Acetobacter aurantius, Acinetobacter baumannii, Actinomyces israelii, Agrobacterium radiobacter, Agrobacterium tumefaciens, Anaplasma phagocytophilum, Azorhizobium caulinodans, Azotobacter vinelandii, Bacillus anthracis, Bacillus brevis, Bacillus cereus, Bacillus fusiformis, Bacillus licheniformis, Bacillus megaterium, Bacillus mycoides, Bacillus stearothermophilus, Bacillus subtilis, Bacillus Thuringiensis, Bacteroides fragilis, Bacteroides gingivalis, Bacteroides melaninogenicus, Bartonella henselae, Bartonella Quintana, Bordetella bronchiseptica, Bordetella pertussis, Borrelia burgdorferi. Brucella abortus, Brucella melitensis, Brucella suis, Burkholderia mallei, Burkholderia pseudomallei, Burkholderia cepacia, Calymmatobacterium granulomatis, Campylobacter coli, Campylobacter fetus, Campylobacter jejuni, Campylobacter pylori, Chlamydia trachomatis, Chlamydophila pneumoniae, Chlamydophila psittaci, Clostridium botulinum, Clostridium difficile, Clostridium perfringens, Clostridium tetani, Corynebacterium diphtheriae, Corynebacterium fusiforme, Coxiella burnetii, Cutibacterium acnes, Cutibacterium avidum, Cutibacterium granulosum, Cutibacterium namnetense, Cutibacterium humerusii, Ehrlichia chaffeensis, Enterobacter cloacae, Enterococcus avium, Enterococcus durans, Enterococcus faecalis, Enterococcus faecium, Enterococcus galllinarum, Enterococcus maloratus, Escherichia coli, Francisella tularensis, Fusobacterium nucleatum, Gardnerella vaginalis, Haemophilus ducreyi, Haemophilus influenzae, Haemophilus parainfluenzae, Haemophilus pertussis, Haemophilus vaginalis, Helicobacter pylori, Klebsiella pneumoniae, Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus casei, Lactococcus lactis, Legionella pneumophila, Listeria monocytogenes, Methanobacterium extroquens, Microbacterium multiforme, Micrococcus luteus, Moraxella catarrhalis, Mycobacterium avium, Mycobacterium bovis, Mycobacterium diphtheriae, Mycobacterium intracellulare, Mycobacterium leprae, Mycobacterium lepraemurium, Mycobacterium phlei, Mycobacterium smegmatis, Mycobacterium tuberculosis, Mycoplasma fermentans, Mycoplasma genitalium, Mycoplasma hominis, Mycoplasma penetrans, Mycoplasma pneumoniae, Neisseria gonorrhoeae, Neisseria meningitidis, Pasteurella multocida, Pasteurella tularensis, Peptostreptococcus, Porphyromonas gingivalis, Prevotella melaninogenica, Propionibacterium acnes, Pseudomonas aeruginosa, Rhizobium radiobacter, Rickettsia prowazekii, Rickettsia psittaci, Rickettsia quintana, Rickettsia rickettsii, Rickettsia trachomae, Rochalimaea henselae, Rochalimaea quintana, Rothia dentocariosa, Salmonella enteritidis, Salmonella typhi, Salmonella typhimurium, Serratia marcescens, Shigella dysenteriae, Spirillum volutans, Staphylococcus aureus, Staphylococcus epidermidis, Stenotrophomonas maltophilia, Streptococcus agalactiae, Streptococcus avium, Streptococcus bovis, Streptococcus cricetus, Streptococcus faceium, Streptococcus faecalis, Streptococcus ferus, Streptococcus gallinarum, Streptococcus lactis, Streptococcus mitior, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus rattus, Streptococcus salivarius, Streptococcus sanguis, Streptococcus sobrinus, Treponema pallidum, Treponema denticola, Vibrio cholerae, Vibrio comma, Vibrio parahaemolyticus, Vibrio vulnificus, Viridans streptococci, Wolbachia, Yersinia enterocolitica, Yersinia pestis, Yersinia pseudotuberculosis antigens, or is selected from poliovirus, rabies virus, hepatitis A, hepatitis B, hepatitis C, yellow fever virus, varicella zoster virus (VZV), measles virus, mumps virus, rubella virus, Japanese encephalitis virus, influenza virus, norovirus, rhinovirus, respiratory syncytial virus (RSV), human metapneumovirus (hMPV), Parainfluenza Virus (PIV), sars-cov-1, sars-cov-2, herpes simplex virus, papilloma virus, cytomegalovirus virus, rotavirus, West Nile virus, dengue virus, chikungunya virus, Epstein-Barr virus (EBV), HIV (AIDS) antigens, or is selected from Plasmodium spp., Leishmania spp., Trypanosoma spp., Schistosome spp. antigens. [0315] Embodiment 148 according to any one of embodiments 146-147, wherein the antigen is from an influenza virus, e.g. is encoded by an RNA sequence comprising SEQ ID NO:3. [0316] Embodiment 149 according to any one of embodiments 146-147, wherein the antigen is from a respiratory syncytial virus (RSV) and/or a human metapneumovirus (hMPV), e.g. is encoded by an RNA sequence comprising SEQ ID NO:7 and/or an RNA sequence comprising SEQ ID NO:8. [0317] Embodiment 150 according to any one of embodiments 146-147, wherein the antigen is from a respiratory syncytial virus (RSV), a human metapneumovirus (hMPV) and/or a Parainfluenza Virus (PIV), e.g. a Parainfluenza Virus type 3 (PIV3). [0318] Embodiment 151 according to any one of embodiments 146-147, wherein the antigen is from Epstein-Barr virus (EBV). [0319] Embodiment 152 according to any one of embodiments 146-147, wherein the antigen is from Porphyromonas gingivalis. [0320] Embodiment 153 according to any one of embodiments 146-152, wherein the mRNA comprises (i) a 5’ cap; (ii) a 5’ UTR; (iii) an ORF encoding an antigen; (iv) a 3’ UTR; and (v) a polyA tail. [0321] Embodiment 154 according to any one of embodiments 146-153, wherein the mRNA comprises at least one, at least two, at least three or more stop codon(s). [0322] Embodiment 155 according to any one of embodiments 144-154, wherein the 5’ cap is selected from the group consisting of 3’-O-Me-m7G(5’)ppp(5’)G (the ARCA cap), G(5’)ppp(5’)A, G(5’)ppp(5’)G, m7G(5’)ppp(5’)A, m7G(5’)ppp(5’)G, m7G(5')ppp(5')(2'OMeA)pG, m7G(5')ppp(5')(2'OMeA)pU, and m7G(5')ppp(5')(2'OMeG)pG. [0323] Embodiment 156 according to any one of embodiments 144-155, wherein the 5’ cap is: [0325] Embodiment 157 according to any one of embodiments 144-156, wherein the 5’ UTR is about 10 to about 5,000 nucleotides in length. [0326] Embodiment 158 according to any one of embodiments 144-157, wherein the 3’ UTR is about 50 to about 5,000 nucleotides in length. [0327] Embodiment 159 according to any one of embodiments 144-158, wherein the 3’ UTR is about 50 to about 1,000 nucleotides in length. [0328] Embodiment 160 according to any one of embodiments 144-159, wherein the polyA tail comprises from at least about 70 adenosine nucleotides to at least about 120 adenosine nucleotides. [0329] Embodiment 161 according to any one of embodiments 144-160, wherein the polyA tail comprises at least about 70, 75, 80, 85, 90, 95, 100, 105, 110, 112, 115 or about 120 adenosine nucleotides. [0330] Embodiment 162 according to any one of embodiments 144-161, wherein the polyA tail comprises at least about 70 adenosine nucleotides or at least about 100 adenosine nucleotides. [0331] Embodiment 163 according to any one of embodiments 144-162, wherein the polyA tail comprises at least about 80 adenosine nucleotides or at least 115 adenosine nucleotides. [0332] Embodiment 164 according to any one of embodiments 144-163, wherein the polyA tail comprises at least about 100 adenosine nucleotides. [0333] Embodiment 165 according to any one of embodiments 140-164, wherein the RNA is a self-replicating mRNA. [0334] Embodiment 166 according to any one of embodiments 140-165, wherein the RNA is a non self-replicating mRNA. [0335] Embodiment 167 according to any one of embodiments 140-166, wherein the RNA is modified or unmodified. [0336] Embodiment 168 according to any one of embodiments 140-167, wherein the RNA comprises at least one modified nucleotide analogue selected from the group consisting of: 1-methyl-adenine, 2-methyl-adenine, 2-methylthio-N-6-isopentenyl-adenine, N6-methyl- adenine, N6-isopentenyl-adenine, 2-thio-cytosine, 3-methyl-cytosine, 4-acetyl-cytosine, 5- methyl-cytosine, 2,6-diaminopurine, 1-methyl-guanine, 2-methyl-guanine, 2,2-dimethyl- guanine, 7-methyl-guanine, inosine, 1-methyl-inosine, pseudouracil (5-uracil), dihydro-uracil, 2-thio-uracil, 4-thio-uracil, 5-carboxymethylaminomethyl-2-thio-uracil, 5- (carboxyhydroxymethyl)-uracil, 5-fluoro-uracil, 5-bromo-uracil, 5-carboxymethylaminomethyl- uracil, 5-methyl-2-thio-uracil, 5-methyl-uracil, N-uracil-5-oxy acetic acid methyl ester, 5- methylaminomethyl-uracil, 5-methoxyaminomethyl-2-thio-uracil, 5’-methoxycarbonylmethyl- uracil, 5-methoxy-uracil, uracil-5-oxyacetic acid methyl ester, uracil-5-oxyacetic acid (v), 1- methyl-pseudouracil, queosine, β-D-mannosyl-queosine, phosphoramidates, phosphorothioates, peptide nucleotides, methylphosphonates, 7-deazaguanosine, 5- methylcytosine, inosine, and combinations thereof. [0337] Embodiment 169 according to any one of embodiments 140-167, wherein the RNA comprises at least one modified nucleotide analogue selected from the group consisting of: pseudouridine, N1-methylpseudouridine, 2-thiouridine, 4’-thiouridine, 5-methylcytosine, 2- thio-l-methyl-1-deaza-pseudouridine, 2-thio-l-methyl-pseudouridine, 2-thio-5-aza-uridine, 2- thio-dihydropseudouridine, 2-thio-dihydrouridine, 2-thio-pseudouridine, 4-methoxy-2-thio- pseudouridine, 4-methoxy-pseudouridine, 4-thio-l-methyl-pseudouridine, 4-thio- pseudouridine, 5-aza-uridine, dihydropseudouridine, 5-methyluridine, 5-methyluridine, 5- methoxyuridine, 2’-O-methyl uridine, and combinations thereof. [0338] Embodiment 170 according to any one of embodiments 140-167 and 169, wherein the RNA comprises at least one modified nucleotide analogue selected from the group consisting of: pseudouridine, N1-methylpseudouridine, 5-methylcytosine, 5-methoxyuridine, and combinations thereof. [0339] Embodiment 171 according to any one of embodiments 140-167, and 169-170, wherein the RNA comprises at least one N1-methylpseudouridine. [0340] Embodiment 172 according to any one of embodiments 140-171, wherein at least from about 20% to about 100%, or from about 30% to about 95%, or from about 40% to about 90%, or from about 50% to about 85%, or from about 60% to about 80%, or from about 70% to about 80% the uracil nucleotides in the RNA are modified nucleotide analogues. [0341] Embodiment 173 according to any one of embodiments 140-172, wherein at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% of the uracil nucleotides in the RNA are modified nucleotide analogues. [0342] Embodiment 174 according to any one of embodiments 146-171, wherein at least from about 20% to about 100%, or from about 30% to about 95%, or from about 40% to about 90%, or from about 50% to about 85%, or from about 60% to about 80%, or from about 70% to about 80% the uracil nucleotides in the ORF are modified nucleotide analogues. [0343] Embodiment 175 according to any one of embodiments 146-171 and 173, wherein at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% of the uracil nucleotides in the ORF are modified nucleotide analogues. [0344] Embodiment 176 according to any one of embodiments 2-175, wherein the nucleic acid and the water-soluble polyanionic polymer are present in w/w ratio from about 1:4000 to about 1:25, or from about 1:2000 to about 1:50, or from 1:1000 to about 1:100, or from about 1:800 to about 1:200, or at about 1:500. [0345] Embodiment 177 according to any one of embodiments 2-176, wherein the nucleic acid and the water-soluble polyanionic polymer are present in w/w ratio of about 1:4000, 1:3500, 1:3000, 1:2500, 1:2000, 1:1500, 1:1000, 1:800, 1:600, 1:500, 1:400, 1:200, 1:100, 1:90, 1:80, 1:70, 1:60, 1:50, 1:45, 1:40, 1:35, 1:30, or about 1:25. [0346] Embodiment 178 according to any one of embodiments 2-177, wherein the water-soluble polyanionic polymer is present in a range of from about 0.1 mg to about 4 mg, or from about 0.2 mg to about 3 mg, or from about 0.3 mg to about 2.5 mg, or from about 0.4 mg to about 2.0 mg, or from about 0.5 mg to about 1.8 mg, or from about 0.6 mg to about 1.5 mg, or from about 0.8 mg to about 1.2 mg, or at about 1.0 mg per dose of said composition. [0347] Embodiment 179 according to any one of embodiments 2-177, wherein the water-soluble polyanionic polymer is present in a range of from about 0.1 mg to about 3 mg, or from about 0.1 mg to about 2 mg, or from about 0.1 mg to about 1 mg, or from about 0.1 mg to about 0.5 mg, or from about 0.1 mg to about 0.4 mg, or from about 0.1 mg to about 0.3 mg, or from about 0.1 mg to about 0.2 mg per dose of said composition. [0348] Embodiment 180 according to any one of embodiments 2-177, wherein the water-soluble polyanionic polymer is present in a range of from about 0.1 mg to about 1.0 mg, or from about 0.1 mg to about 0.9 mg, or from about 0.1 mg to about 0.8 mg, or from about 0.1 mg to about 0.7 mg, or from 0.1 mg to about 0.6 mg, or from about 0.1 mg to about 0.5 mg per dose of said composition. [0349] Embodiment 181 according to any one of embodiments 2-177, wherein the water-soluble polyanionic polymer is present in a range of from about 0.1 mg to about 0.5 mg, or from about 0.2 mg to about 0.5 mg, or from about 0.3 mg to about 0.5 mg, or from about 0.4 mg to about 0.5 mg per dose of said composition. [0350] Embodiment 182 according to any one of embodiments 2-177, wherein the water-soluble polyanionic polymer is present at about 0.1 mg, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.5, 2.8, 3.0, 3.5, or at about 4.0 mg per dose of said composition. [0351] Embodiment 183 according to any one of embodiments 2-177, wherein the water-soluble polyanionic polymer is present at about 0.1 mg, 0.125, 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 mg per dose of said composition. [0352] Embodiment 184 according to any one of embodiments 2-177, wherein the water-soluble polyanionic polymer is present at about 0.1 mg, 0.125, 0.2, 0.25, 0.3, 0.4, or at about 0.5 mg per dose of said composition. [0353] Embodiment 185, wherein the embodiment is a composition, e.g. an immunogenic composition, comprising: [0354] - at least one water-soluble polyanionic polymer, wherein said water-soluble polyanionic polymer is a polyacrylic acid polymer, or a pharmaceutically acceptable thereof, [0355] - at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, wherein said nucleic acid carrier is a lipid nanoparticle (LNP), and [0356] - at least one nucleic acid encoding at least one antigen, wherein said nucleic acid is an mRNA. [0357] Embodiment 186, according to embodiment 185, wherein the at least one water-soluble polyanionic polymer, the at least one nucleic acid carrier and/or the at least one nucleic acid are according to any one of embodiments 8-12, 15-19, 23-78, 85-139 and 144- 184. [0358] Embodiment 187, wherein the embodiment is an immunogenic composition, such as a vaccine, comprising a prophylactically effective amount or a therapeutically effective amount of the composition according to any one of the embodiments 7-186. [0359] Embodiment 188, wherein the embodiment is a kit-of-parts comprising at least a first container and at least a second container, wherein: [0360] - the first container comprises a first composition comprising at least one water- soluble polyanionic polymer, [0361] - the second container comprises a second composition comprising at least one nucleic acid carrier and at least one nucleic acid. [0362] Embodiment 189 according to embodiment 188, wherein the at least one water-soluble polyanionic polymer, the at least one nucleic acid carrier and/or the at least one nucleic acid are according to any one of embodiments 6-184. [0363] Embodiment 190, wherein the embodiment is an immunogenic composition for use in an immunization method for eliciting an immune response, e.g. a protective immune response, against an antigen in an individual in need thereof, said immunogenic composition comprising at least one water-soluble polyanionic polymer, at least one nucleic acid carrier, and at least one nucleic acid encoding at least said antigen. [0364] Embodiment 191, wherein the embodiment is an immunogenic composition for use in an immunization method in an individual in need thereof, wherein the immunogenic composition is as defined in embodiment 190. [0365] Embodiment 192 according to embodiment 191, wherein the immunization method is for inducing an immune response with an antigen-encoding nucleic acid (e.g. mRNA) dose-sparing effect. [0366] Embodiment 193 according to embodiment 192, wherein the composition may comprise an amount of the antigen-encoding nucleic acid at least 2 times lower than the amount of antigen-encoding nucleic acid of an immunogenic composition comprising the same nucleic acid carrier and the same nucleic acid and inducing a similar or comparable immune response in absence of the water-soluble polyanionic polymer. [0367] Embodiment 194 according to any one of embodiments 192 to 193, wherein the composition may comprise an amount of antigen-encoding nucleic acid from at least 2 to about 20 times, or from 4 to 16 times, or from 5 to 14 times, or from 5 to 12 times, or from 8 to 10 times lower than the amount of antigen-encoding nucleic acid of an immunogenic composition comprising the same nucleic acid carrier and the same nucleic acid and inducing a similar or comparable immune response in absence of the water-soluble polyanionic polymer. [0368] Embodiment 195, wherein the embodiment is an immunogenic composition for use in an immunization method in an individual in need thereof, said immunogenic composition comprising at least one water-soluble polyanionic polymer, at least one nucleic acid carrier, and at least one nucleic acid encoding at least said antigen, wherein said at least one water- soluble polyanionic polymer allows obtaining an antigen-encoding nucleic acid dose-sparing effect. [0369] Embodiment 196, wherein the embodiment is an immunogenic composition for use in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, said immunogenic composition comprising at least one water- soluble polyanionic polymer, at least one nucleic acid carrier, and at least one nucleic acid encoding at least said antigen, wherein said composition allows obtaining a nucleic acid dose- sparing effect, wherein the antigen-encoding nucleic acid dose-sparing effect allows the use in said composition of less than one-tenth of the amount of said nucleic acid required for eliciting said immune response in absence of said water-soluble polyanionic polymer. [0370] Embodiment 197, wherein the embodiment is a kit-of-parts for use in an immunization method for eliciting an immune response, e.g. a protective immune response, against an antigen in an individual in need thereof, said kit-of-parts comprising at least a first container and at least a second container, wherein: [0371] - the first container comprises a first composition comprising at least one water- soluble polyanionic polymer, [0372] - the second container comprises a second composition comprising least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen, [0373] and wherein the immunization method comprises administrating to said individual, e.g. by intramuscular injection, the first and second compositions simultaneously, sequentially or separately. [0374] Embodiment 198 according to any one of embodiments 190-197, wherein the at least one water-soluble polyanionic polymer, the at least one cationic, or ionizable cationic, lipid, and the at least one nucleic acid encoding at least one antigen are according to any one of embodiments 6-184. [0375] Embodiment 199, wherein the embodiment is a use of a water-soluble polyanionic polymer in an immunogenic composition for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response, e.g. a protective immune response, against said antigen in an individual in need thereof, said immunogenic composition further comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least said antigen. [0376] Embodiment 200, wherein the embodiment is a use of a water-soluble polyanionic polymer in an immunogenic composition for reducing the antigen-encoding nucleic acid quantity in the immunogenic composition to be administered in an immunization method for eliciting an immune response against said antigen in an individual in need thereof, said immunogenic composition further comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least said antigen. [0377] Embodiment 201, wherein the embodiment is a use of a water-soluble polyanionic polymer in an immunogenic composition for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response, e.g. a protective immune response, against an antigen in an individual in need thereof, said immunogenic composition further comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least said antigen, wherein the antigen-encoding nucleic acid dose- sparing effect allows the use in said composition of less than an half of the amount of said nucleic acid required for eliciting said immune response in absence of said water-soluble polyanionic polymer. [0378] Embodiment 202, wherein the embodiment is a use of a water-soluble polyanionic polymer in combination with a formulation comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen for obtaining an antigen- encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response against said antigen in an individual in need thereof. [0379] Embodiment 203 according to any one of embodiments 190-202, wherein the immune response is a predominantly Th1-type immune response. [0380] Embodiment 204, wherein the embodiment is a use of a water-soluble polyanionic polymer in an immunogenic composition for adjuvanting said immunogenic composition, the immunogenic composition further comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen. [0381] Embodiment 205, wherein the embodiment is a use of a water-soluble polyanionic polymer as adjuvant in an immunogenic composition, the immunogenic composition further comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen. [0382] Embodiment 206, wherein the embodiment is a use of a water-soluble polyanionic polymer in the manufacture of an immunogenic composition, the composition being for use in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, the composition comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least said antigen. [0383] Embodiment 207, wherein the embodiment is a water-soluble polyanionic polymer, for use in combination with at least one nucleic acid carrier and at least one nucleic acid encoding at least an antigen, for use in an immunization method for eliciting an immune response against said antigen in an individual in need thereof. [0384] Embodiment 208, wherein the embodiment is a use of a water-soluble polyanionic polymer, in combination with at least one nucleic acid carrier and at least one nucleic acid encoding at least an antigen, in the manufacture of an immunogenic composition, the composition being for use in an immunization method for eliciting an immune response against said antigen in an individual in need thereof. [0385] Embodiment 209, wherein the embodiment is an immunization method for eliciting an immune response against an antigen in an individual in need thereof, comprising administering to said individual a water-soluble polyanionic polymer, in combination with at least one nucleic acid carrier and at least one nucleic acid encoding at least said antigen, in the manufacture of an immunogenic composition. [0386] Embodiment 210, wherein the embodiment is a use of a water-soluble polyanionic polymer as adjuvant in the manufacture of an immunogenic composition, the composition being for use in an immunization method for eliciting an immune response, e.g. a protective immune response, against an antigen in an individual in need thereof, the composition comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least said antigen. [0387] Embodiment 211, wherein the embodiment is a use of a water-soluble polyanionic polymer in the manufacture of a kit-of-parts, the kit-of-parts being for use in an immunization method for eliciting an immune response, e.g. a protective immune response, against an antigen in an individual in need thereof, the kit-of-parts comprising at least a first container and at least a second container, wherein: [0388] - the first container comprises a first composition comprising at least one water- soluble polyanionic polymer, [0389] - the second container comprises a second composition comprising least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen, [0390] and wherein the immunization method comprises administering to said individual, e.g. by intramuscular injection, the first and second compositions simultaneously, sequentially or separately. [0391] Embodiment 212, wherein the embodiment is a use of a combination in the manufacture of an immunogenic composition, the composition being for use in an immunization method for eliciting an immune response, e.g. a protective immune response, against an antigen in an individual in need thereof, the combination comprising at least one water-soluble polyanionic polymer, at least one nucleic acid carrier, and at least one nucleic acid encoding at least said antigen. [0392] Embodiment 213, wherein the embodiment is a method for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response, e.g. a protective immune response, against said antigen in an individual in need thereof, the immunization method comprising a step of administering to said individual, e.g. by intramuscular injection, an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water- soluble polyanionic polymer. [0393] Embodiment 214, wherein the embodiment is a method for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response, e.g. a protective immune response, against said antigen in an individual in need thereof, the immunization method comprising a step of administering to said individual, e.g. by intramuscular injection, an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water- soluble polyanionic polymer, wherein the antigen-encoding nucleic acid dose-sparing effect allows the use in said composition of less than one-tenth of the amount of said nucleic acid required for eliciting said immune response in absence of said water-soluble polyanionic polymer. [0394] Embodiment 215, wherein the embodiment is a method for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response, e.g. a protective immune response, against said antigen in an individual in need thereof, the immunization method comprising administering to said individual, e.g. by intramuscular injection, a combination comprising a water-soluble polyanionic polymer with a formulation comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen. [0395] Embodiment 216, wherein the embodiment is a method of adjuvanting an immune response in an immunization method for eliciting said immune response, e.g. a protective immune response, against an antigen in an individual in need thereof, the immunization method comprising a step of administering to said individual, e.g. by intramuscular injection, an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water-soluble polyanionic polymer. [0396] Embodiment 217, wherein the embodiment is a method of adjuvanting an immune response in an immunization method for eliciting said immune response against an antigen in an individual in need thereof, the immunization method comprising a step of administering to said individual, e.g. by intramuscular injection, an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water-soluble polyanionic polymer, the method comprising a step of manufacturing said immunogenic composition by a method comprising at least a step adding said one water-soluble polyanionic polymer to a formulation comprising said at least one nucleic acid carrier and said at least one nucleic acid encoding at least said antigen. [0397] Embodiment 218, wherein the embodiment is a method for adjuvanting an immunogenic formulation, e.g. a vaccine, comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least an antigen, in an immunization method for eliciting an immune response against said antigen in an individual in need thereof, the immunization method comprising a step of administering to said individual, e.g. by intramuscular injection, said formulation in combination with at least one water-soluble polyanionic polymer. [0398] Embodiment 219, wherein the embodiment is a method for adjuvanting an immunogenic formulation comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least an antigen, in an immunization method for eliciting an immune response against said antigen in an individual in need thereof, the method comprising a step of adding at least one water-soluble polyanionic polymer to said formulation to obtain an immunogenic composition, and administering to said individual, e.g. by intramuscular injection, the immunogenic composition thus obtained. [0399] Embodiment 220 according to any one of embodiments 206-219, wherein the immune response is a predominantly Th1-type immune response. [0400] Embodiment 221, wherein the embodiment is a method for manufacturing an immunogenic composition, the method comprising at least a step of adding at least one water- soluble polyanionic polymer to a formulation comprising said at least one nucleic acid carrier and said at least one nucleic acid encoding at least one antigen. [0401] Embodiment 222, wherein the embodiment is a method for manufacturing a kit-of-parts, the method comprising at least a step of preparing at least a first container and a step of preparing at least a second container, wherein: [0402] - the first container comprises a first composition comprising at least one water- soluble polyanionic polymer, [0403] - the second container comprises a second composition comprising least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen. [0404] Embodiment 223, wherein the embodiment is a method for eliciting an immune response against an antigen in an individual in need thereof, the method comprising at least a step of administering to said individual an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water-soluble polyanionic polymer. [0405] Embodiment 224, wherein the embodiment is a method for eliciting a prophylactic immune response against an antigen in an individual in need thereof, the method comprising at least a step of administering to said individual an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water-soluble polyanionic polymer. [0406] Embodiment 225, wherein the embodiment is a method for eliciting a therapeutic immune response against an antigen in an individual in need thereof, the method comprising at least a step of administering to said individual, e.g. by intramuscular injection, an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water-soluble polyanionic polymer. [0407] Embodiment 226, wherein the embodiment is a method for eliciting an immune response against an antigen in an individual in need thereof, the method comprising at least a step of administering to an individual in need thereof, e.g. by intramuscular injection, at least a first composition and at least a second composition from a kit-of-parts, wherein said kit-of- parts comprises a first container and at least a second container, wherein: [0408] - the first container comprises said first composition, said first composition comprising at least one water-soluble polyanionic polymer, [0409] - the second container comprises a second composition, said composition comprising least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen, [0410] and wherein the step of administering to said individual comprises a simultaneous, a sequential or a separate administration of said first and said second compositions. [0411] Embodiment 227 according to any one of embodiments 199-226, wherein the at least one water-soluble polyanionic polymer, the at least one cationic, or ionizable cationic, lipid, and the at least one nucleic acid encoding at least one antigen are according to any one of embodiments 6-184. [0412] Embodiment 228 according to embodiment 227, wherein the at least one water-soluble polyanionic polymer is a polyacrylic acid polymer. [0413] Embodiment 229 according to any one of embodiments 227-228, wherein the at least one cationic, or ionizable cationic, lipid is GL-HEPES-E3-E12-DS-4-E10, ALC-0315, SM-102 or MC3, e.g. GL-HEPES-E3-E12-DS-4-E10. [0414] Embodiment 230 according to any one of embodiments 227-229, wherein the at least one nucleic acid encodes an antigen from influenza, from RSV, from hMPV, from PIV, from EBV and/or from Porphyromonas gingivalis. [0415] Embodiment 231 according to embodiment 230, wherein at least one nucleic acid encodes an antigen from RSV and at least one nucleic acid encodes an antigen from hMPV. [0416] Embodiment 232 according to embodiment 230, wherein at least one nucleic acid encodes an antigen from RSV, at least one nucleic acid encodes an antigen from hMPV and/or at least one nucleic acid encodes an antigen from PIV (e.g. from PIV3). [0417] Embodiment 233 according to embodiment 230, wherein at least one nucleic acid encodes an antigen from EBV. [0418] Embodiment 234 according to embodiment 230, wherein at least one nucleic acid encodes an antigen from Porphyromonas gingivalis. [0419] Embodiment 235 according to embodiment 7, wherein the at least one water- soluble polyanionic polymer is a polyacrylic acid polymer. [0420] Embodiment 236 according to embodiment 235, wherein the at least one nucleic acid carrier is a LNP comprising the ionizable cationic lipid GL-HEPES-E3-E12-DS-4- E10, ALC-0315, SM-102 or MC3, e.g. GL-HEPES-E3-E12-DS-4-E10. [0421] Embodiment 237 according to any one of embodiments 235-236, wherein the at least one nucleic acid encodes an antigen from influenza, from RSV, from hMPV, from PIV, from EBV and/or from Porphyromonas gingivalis. [0422] Embodiment 238 according to embodiment 237, wherein at least one nucleic acid encodes an antigen from RSV (e.g. said antigen is encoded by an RNA sequence comprising SEQ ID NO: 7) and at least one nucleic acid encodes an antigen from hMPV (e.g. said antigen is encoded by an RNA sequence comprising SEQ ID NO: 8). [0423] Embodiment 239 according to embodiment 237, wherein at least one nucleic acid encodes an antigen from RSV, at least one nucleic acid encodes an antigen from hMPV and/or at least one nucleic acid encodes an antigen from PIV (e.g. from PIV3). [0424] Embodiment 240 according to embodiment 237, wherein at least one nucleic acid encodes an antigen from influenza (e.g. said antigen is encoded by an RNA sequence comprising SEQ ID NO: 3). [0425] Embodiment 241 according to embodiment 237, wherein at least one nucleic acid encodes an antigen from EBV. [0426] Embodiment 242 according to embodiment 237, wherein at least one nucleic acid encodes an antigen from Porphyromonas gingivalis. [0427] Embodiment 243 according to any one of embodiments 223-242, wherein the immune response is a predominantly Th1-type immune response. Compositions and immunogenic compositions [0428] The disclosure relates to a composition comprising: [0429] - at least one water-soluble polyanionic polymer, and [0430] - at least one nucleic acid carrier. [0431] Such a composition may further comprise at least one nucleic acid. [0432] The disclosure also relates to a composition comprising: [0433] - at least one water-soluble polyanionic polymer, and [0434] - at least one nucleic acid. [0435] Such a composition may further comprise at least one nucleic acid carrier. [0436] The disclosure also relates to a composition comprising: [0437] - at least one water-soluble polyanionic polymer, [0438] - at least one nucleic acid carrier, and [0439] - at least one nucleic acid. [0440] The nucleic acid present in a composition of the disclosure may encode at least one antigen. [0441] The compositions of the disclosure may be immunogenic compositions. [0442] An immunogenic composition of the disclosure may be a multivalent composition. As used herein, the term “multivalent” means a composition containing more than one antigen whether from the same species, from different species and/or from different genera. [0443] Further to a water-soluble polyanionic polymer, a nucleic acid carrier, and a nucleic acid encoding at least one antigen, a composition of the disclosure may comprise at least one “pharmaceutically acceptable carrier”. Pharmaceutically acceptable carrier and pharmaceutically acceptable vehicle are interchangeably used and refer to a vehicle for containing the components of an immunogenic composition of the disclosure and which can be administered into an individual without adverse effects. [0444] Suitable pharmaceutically acceptable carriers are known in the art and may include, but are not limited to, sterile water, saline, glucose, dextrose, or buffered solutions. Carriers may include auxiliary agents including, but not limited to, diluents, stabilizers (i.e., sugars and amino acids), preservatives, wetting agents, emulsifying agents, pH buffering agents, viscosity enhancing additives, colors and the like. [0445] A composition of the disclosure can be administered in dosages and by techniques well known to those skilled in the medical or veterinary arts, taking into consideration such factors as the age, sex, weight, species and condition of the recipient individual, and the route of administration. [0446] The route of administration can be percutaneous, via mucosal administration (e.g., oral, nasal, anal, vaginal) or via a parenteral route (intradermal, intramuscular, subcutaneous, intravenous, or intraperitoneal). Compositions can be administered alone or can be co-administered or sequentially administered with other treatments or therapies. [0447] Forms of administration may include suspensions and preparations for subcutaneous, intradermal, intramuscular or intravenous administration (e.g., injectable administration) such as sterile suspensions or emulsions. [0448] A pharmaceutically acceptable carrier may be a diluent, or an excipient such as sterile water, physiological saline, glucose, or the like. The compositions can contain pharmaceutically acceptable auxiliary substances such as wetting or emulsifying agents, pH buffering agents, adjuvants, gelling or viscosity enhancing additives, preservatives, flavoring agents, colors, and the like, depending upon the route of administration and the preparation desired. [0449] Standard pharmaceutical texts, such as “Remington's Pharmaceutical Sciences,” 1990, may be consulted to prepare suitable compositions without undue experimentation. Water-soluble polyanionic polymer [0450] For a polymer to be considered water-soluble in the context of the disclosure, it must dissolve in water at a concentration of at least 1 wt% (percentage by weight or % w/w) at room temperature (25°C) to form a clear or slightly hazy solution. This solubility is primarily driven by the presence of the anionic groups along the polymer backbone. These charged groups form hydrogen bonds with water molecules, creating favorable interactions that overcome the intermolecular forces within the polymer and facilitate dissolution. [0451] Compositions and immunogenic compositions of the disclosure comprise at least one water-soluble polyanionic polymer. [0452] In some embodiments, the water-soluble polyanionic polymer may be an adjuvant. [0453] In some embodiments, the water-soluble polyanionic polymer may be present in immunogenic compositions of the disclosure for adjuvanting the compositions. [0454] In some embodiments, the water-soluble polyanionic polymer may be present in immunogenic compositions of the disclosure as an antigen-encoding nucleic acid dose- sparing agent. [0455] In some embodiments, the water-soluble polyanionic polymer may be present in immunogenic compositions of the disclosure for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method. [0456] In some embodiments, an immunogenic composition of the disclosure may have an increased immunogenicity in comparison with a composition comprising a same nucleic acid and a same nucleic acid carrier and not comprising a water-soluble polyanionic polymer. [0457] Water-soluble polyanionic polymers are macromolecules containing a plurality of repeating units. Each repeating unit within the polymer chain bears a negative charge (anionic). This anionic character arises from the incorporation of functional groups like carboxylic acid (-COOH), sulfonic acid (-SO3H), or phosphate groups (-PO4^3-). The presence of these charged groups allows the polymer to interact favorably with water molecules through hydrogen bonding, leading to water solubility. [0458] The repeating units themselves can be derived from a variety of monomers. [0459] The repeating units within a water-soluble polyanionic polymer can be arranged in different ways, leading to distinct polymer architectures: such as homopolymers, heteropolymers or copolymers. [0460] Homopolymers consist entirely of repeating units derived from a single type of monomer. For instance, a homopolymer of acrylic acid has every repeating unit containing an acrylic acid moiety. [0461] Copolymers contain repeating units derived from two or more different types of repeating units. The arrangement of these units can be random, alternating, or block- copolymers. Random copolymers exhibit a statistical distribution of monomers throughout the chain, while alternating copolymers have a defined alternating sequence of monomers. Block copolymers consist of distinct blocks of different monomers, leading to segregated regions within the polymer chain. [0462] Heteropolymers are similar to copolymers in that they also contain repeating units derived from multiple monomers. However, in heteropolymers, the monomers are linked together in a non-repeating manner. [0463] In some embodiments, the water-soluble polyanionic polymers may be heteropolymers, copolymers or homopolymers. [0464] In some embodiments, the water-soluble polyanionic polymers may be heteropolymers. [0465] In some embodiments, the water-soluble polyanionic polymers may be homopolymers. [0466] In some embodiments, the water-soluble polyanionic polymer may be selected from the group consisting of: polyacrylic acid polymer, polymethacrylic acid polymer, hyaluronic acid polymer, polyglutamic acid polymer, polyaspartic acid polymer, polystyrenesulfonic acid polymer, heparin polymer, dextran sulfate polymer, carboxymethylcellulose polymer, alginic acid polymer, combinations thereof, and pharmaceutically acceptable salts thereof. [0467] In some embodiments, the water-soluble polyanionic polymer may be selected from the group consisting of: polyacrylic acid polymer, polylactic acid, polyglycolic acid, combinations thereof, and pharmaceutically acceptable salts thereof. [0468] In some embodiments, the water-soluble polyanionic polymer may be a polyacrylic acid polymer or a pharmaceutically acceptable salt thereof. [0469] In some embodiments, the water-soluble polyanionic polymer may be exclusively composed of units corresponding to a salt of acrylic acid or is exclusively composed of units corresponding to the free acid form of acrylic acid and of units corresponding to a salt of acrylic acid. [0470] In some embodiments, the water-soluble polyanionic polymer may be a pharmaceutically acceptable salt of a polyacrylic acid polymer. [0471] A pharmaceutically acceptable salt of a water-soluble polymer refers to a form of the polymer that is created by the ionic association of the polymer with a pharmaceutically acceptable counterion. These counterions are typically derived from organic or inorganic acids or bases that are deemed safe for human or animal administration. [0472] Examples of pharmaceutically acceptable cations suitable for forming salts with water-soluble polyanionic polymers include alkali metal cations (e.g., sodium (Na⁺), potassium (K⁺)), alkaline earth metal cations (e.g., magnesium (Mg²⁺), calcium (Ca²⁺)), or ammonium cations (NH₄ ⁺) and organic cations derived from pharmaceutically acceptable organic acids (e.g., triethylamine (Et₃N⁺), N-methylglucamine). [0473] In some embodiments, the pharmaceutically acceptable salt of a polyacrylic acid polymer may be a sodium salt. [0474] In some embodiments, the water-soluble polyanionic polymer may be a sodium salt of a polyacrylic acid polymer. [0475] In some embodiments, the polyacrylic acid polymer salt may comprise less than 0.005%, preferably less than 0.001%, w/w of oxidizing agents, based on the total dry weight of said polyacrylic acid polymer salt. [0476] In some embodiments, the polyacrylic acid polymer salt may comprise less than 0.005%, preferably less than 0.001%, w/w of persulfates, based on the total dry weight of said polyacrylic acid polymer salt. [0477] The polyacrylic acid polymer salt can be in a solid form (precipitate or powder) or in a liquid formulation. A liquid formulation will include the polyacrylic acid polymer salt and an aqueous solution. Such a formulation may have a pH in the range of 5.5 to 8.0. This pH can be obtained by incorporation of a base, like NaOH, in the aqueous solution. The aqueous solution can be a buffered aqueous solution, obtained with a buffer such as a phosphate buffer, a TRIS (2-amino-2-hydroxymethyl-1,3-propanediol), Hepes (acide 4-(2-hydroxyethyl)-1- piperazine ethane sulfonique), histidine or citrate buffer. The liquid formulation may also comprise one or several additional salts, such as NaCl. [0478] The water-soluble polyanionic polymer may be crosslinked. [0479] The water-soluble polyanionic polymer may be non-crosslinked. [0480] In some embodiments, the water-soluble polyanionic polymer may be a linear polymer. [0481] In some embodiments, the water-soluble polyanionic polymer may be a branched polymer. [0482] In some embodiments, the water-soluble polyanionic polymer may comprise less than 0.005% w/w of free monomer, based on the total dry weight of the polymer. [0483] In some embodiments, the polyacrylic acid polymer salt may comprise less than 0.005% w/w of acrylic acid monomer in free acid form or salt form, based on the total dry weight of said polyacrylic acid polymer salt. [0484] A polyacrylic acid polymer salt suitable for the disclosure may be as disclosed in WO 2017/218819. [0485] The weight average molecular weight (Mw) is a statistical measure of the average mass of polymer chains within a sample. The Mw of a polymer suitable for the disclosure may range from about 1,000 to about 1,000,000 Daltons. [0486] Several analytical techniques can be employed to determine the Mw of water- soluble polyanionic polymers. As example of usable methods, one may cite: [0487] Concentration, weight average molecular weight (Mw), number average molecular weight (Mn), Mark Houwink slope, intrinsic viscosity and hydrodynamic radius of a polymer of the disclosure may be determined by Size Exclusion Chromatography, which is one of the most suitable methods for determining Mw and Mn, especially high performance size exclusion chromatography (HPSEC). A suitable protocol is disclosed in the Examples section. HPSEC analyses may be performed on a VISCOTEK GPCmax VE2501 system (MALVERN INSTRUMENTS, MALVERN, UK) comprising a HPLC pump with built-in degasser and autosampler with a 100 µl injection loop. The system may be equipped with a VISCOTEK TDA 302 detector with right angle laser light scattering (RALLS), refractive index (RI), and viscosity (VIS) detection. OMNISEC 4.7 software may be used for the acquisition and analysis of SEC data. The detectors can be calibrated with a 100 kDa pullulan standard (MALVERN INSTRUMENTS) in PBS. [0488] Gel Permeation Chromatography (GPC): This technique separates polymer chains based on their size. Larger molecules elute (flow out) of the column first, while smaller molecules are retained for a longer duration. By analyzing the elution profile and using appropriate calibration standards, the Mw of the polymer sample can be calculated. [0489] Light Scattering Techniques: These methods, such as Multi-Angle Light Scattering (MALS), measure the amount of light scattered by the polymer molecules in solution. The scattered light intensity is related to the size and mass of the molecules, allowing for the determination of Mw. [0490] Viscometry: This technique measures the resistance of a fluid (polymer solution) to flow. The viscosity of a polymer solution is influenced by the size and conformation of the polymer chains. By relating the measured viscosity to known standards or theoretical models, the Mw of the polymer can be estimated. [0491] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 60 to about 650 kDa. [0492] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 80 to about 620 kDa. [0493] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 80 to about 600 kDa. [0494] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 100 to about 600 kDa. [0495] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 100 to about 580 kDa. [0496] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 120 to about 600 kDa. [0497] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 150 to about 580 kDa. [0498] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 200 to about 540 kDa. [0499] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 250 to about 500 kDa. [0500] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 300 to about 400 kDa. [0501] In some embodiments, the polymer may have a weight average molecular weight Mw in the range of 350 to 650 kDa. [0502] In some embodiments, the polymer may have a weight average molecular weight Mw in the range of 380 to 620 kDa. [0503] In some embodiments, the polymer may have a weight average molecular weight Mw in the range of 400 to 600 kDa [0504] In some embodiments, the polymer may have a weight average molecular weight Mw in the range of 400 to 500 kDa. [0505] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) of about 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 2280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, or about 650 kDa. [0506] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) from about 60, or from about 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 2280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, or from about 640 to about 650 kDa. [0507] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) from about 60 to about 70, or about 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 2280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640 or about to 650 kDa. [0508] In some embodiments, the water-soluble polyanionic polymers may be linear or branched. [0509] In some embodiments, the water-soluble polyanionic polymer may be linear. [0510] In some embodiments, the water-soluble polyanionic polymer may have a polydispersity index (PDI) below or equal to about 4, or below or equal to about 3.5, or below or equal to about 3, or below or equal to about 2.5. [0511] The PDI reflects the distribution of individual chain lengths of a polymer. The PDI is a dimensionless parameter defined as the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the polymer. [0512] Mn represents the molar mass weighted according to the number of monomer units (n) contained in each of the chains within the sample. A PDI value of 1 indicates a monodisperse polymer, where all chains have identical lengths. [0513] Several techniques can be employed to measure the PDI of water-soluble polyanionic polymers: [0514] Gel Permeation Chromatography (GPC): Similar to Mw determination using GPC, the technique separates polymer chains based on size. By analyzing the detector response and employing appropriate calibration standards, both Mw and Mn can be obtained. The PDI is then calculated as the ratio of these two values. [0515] Field-Flow Fractionation (FFF): This technique separates polymer chains based on both size and hydrodynamic radius. By analyzing the elution profile, Mw and Mn can be determined, allowing for the calculation of PDI. [0516] Alternatively, the PDI of a polymer may be calculated as Mw/Mn, with Mw and Mn being measured by HPSEC as above-indicated. [0517] In some embodiments, the water-soluble polyanionic polymer may have a polydispersity index below or equal to about 4, 3.9, 3.8, 3.7, 3.6, 3.5, 3.4, 3.3, 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, or below or equal to about 2.5. [0518] In some embodiments, the water-soluble polyanionic polymer may have a polydispersity index from about 4.0, 3.9, 3.8, 3.7, 3.6, 3.5, 3.4, 3.3, 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, 2.5 to about 1.0. [0519] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 60 to about 650 kDa and a polydispersity index below or equal to 4. [0520] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 80 to about 620 kDa and a polydispersity index below or equal to 4. [0521] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 80 to about 600 kDa and a polydispersity index below or equal to 4. [0522] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 100 to about 600 kDa and a polydispersity index below or equal to 4. [0523] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 100 to about 580 kDa and a polydispersity index below or equal to 4. [0524] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 120 to about 600 kDa and a polydispersity index below or equal to 4. [0525] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 150 to about 580 kDa and a polydispersity index below or equal to 4. [0526] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 200 to about 540 kDa and a polydispersity index below or equal to 4. [0527] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 250 to about 500 kDa and a polydispersity index below or equal to 4. [0528] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 300 to about 400 kDa and a polydispersity index below or equal to 4. [0529] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 60 to about 650 kDa and a polydispersity index below or equal to 2.5. [0530] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 80 to about 620 kDa and a polydispersity index below or equal to 2.5. [0531] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 80 to about 600 kDa and a polydispersity index below or equal to 2.5. [0532] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 100 to about 600 kDa and a polydispersity index below or equal to 2.5. [0533] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 100 to about 580 kDa and a polydispersity index below or equal to 2.5. [0534] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 120 to about 600 kDa and a polydispersity index below or equal to 2.5. [0535] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 150 to about 580 kDa and a polydispersity index below or equal to 2.5. [0536] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 200 to about 540 kDa and a polydispersity index below or equal to 2.5. [0537] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 250 to about 500 kDa and a polydispersity index below or equal to 2.5. [0538] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 300 to about 400 kDa and a polydispersity index below or equal to 2.5. [0539] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 60 to about 650 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0540] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 80 to about 620 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0541] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 80 to about 600 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0542] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 100 to about 600 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0543] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 100 to about 580 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0544] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 120 to about 600 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0545] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 150 to about 580 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0546] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 200 to about 540 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0547] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 250 to about 500 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0548] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight (Mw) in the range of about 300 to about 400 kDa and a polydispersity index in the range of about 1.6 to about 2.5. [0549] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight Mw in the range of 350 to 650 kDa and a polydispersity index below or equal to 4. [0550] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight Mw in the range of 380 to 620 kDa and a polydispersity index below or equal to 4. [0551] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight Mw in the range of 400 to 600 kDa and a polydispersity index below or equal to 4. [0552] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight Mw in the range of 350 to 650 kDa and a polydispersity index below or equal to 2.5. [0553] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight Mw in the range of 380 to 620 kDa and a polydispersity index below or equal to 2.5. [0554] In some embodiments, the water-soluble polyanionic polymer may have a weight average molecular weight Mw in the range of 400 to 600 kDa and a polydispersity index below or equal to 2.5. [0555] In some embodiments, the water-soluble polyanionic polymer may have a Mark- Houwink slope higher or equal to 0.7. [0556] The Mark-Houwink equation relates the intrinsic viscosity ([η]) of a polymer to its weight average molecular weight (Mw). The intrinsic viscosity represents the inherent ability of a polymer solution to resist flow at a specific concentration, independent of polymer-solvent interactions. The Mark-Houwink equation takes the form: [0557] [η] = K * Mw^a [0558] where: [0559] [η] is the intrinsic viscosity (dL/g) [0560] K is the Mark-Houwink constant (specific to the polymer-solvent system) [0561] Mw is the weight average molecular weight (Da) [0562] a is the Mark-Houwink slope (dimensionless) [0563] The Mark-Houwink slope (a) provides information about the polymer chain conformation in solution. [0564] A Mark-Houwink slope a ≈ 0.5 indicates a random coil conformation, where the polymer chain is highly flexible and exhibits a relatively low viscosity for its size. [0565] A Mark-Houwink slope 0.5 < a < 1 suggests a more extended conformation, with the polymer chain exhibiting a greater viscosity increase with increasing molecular weight compared to a random coil. [0566] A Mark-Houwink slope a ≈ 1 represents a rigid rod-like conformation, where the polymer chain is very stiff and displays a significant increase in viscosity with increasing molecular weight. [0567] The following technique can be employed to measure the intrinsic viscosity and subsequently determine the Mark-Houwink slope: [0568] Capillary viscometry: This technique measures the flow time of a polymer solution through a capillary tube compared to the flow time of the pure solvent. By measuring at varying polymer concentrations and extrapolating to zero concentration, the intrinsic viscosity can be obtained. [0569] By combining intrinsic viscosity measurements with known Mw values for a series of polymer samples, the Mark-Houwink slope (a) can be calculated using linear regression analysis. Understanding the Mark-Houwink relationship for water-soluble polyanionic polymers employed in formulations of the disclosure allows for the prediction of their solution behavior based on molecular weight and facilitates the design of formulations with optimal properties. [0570] A polyacrylic acid polymer suitable for the disclosure may have a Mark Houwink slope higher or equal to 0.7. When in solution, the polyacrylic acid polymer is in the form of a salt, this Mark Houwink slope concerns the polyacrylic acid polymer salt. [0571] In some embodiments, the water-soluble polyanionic polymer may be present in a composition of the disclosure in a range of from about 0.1 mg to about 4 mg, or from about 0.2 mg to about 3 mg, or from about 0.3 mg to about 2.5 mg, or from about 0.4 mg to about 2.0 mg, or from about 0.5 mg to about 1.8 mg, or from about 0.6 mg to about 1.5 mg, or from about 0.8 mg to about 1.2 mg, per dose of the composition. [0572] In some embodiments, the water-soluble polyanionic polymer may be present in a composition of the disclosure in a range of from about 0.1 mg to about 3 mg, or from about 0.1 mg to about 2 mg, or from about 0.1 mg to about 1 mg, or from about 0.1 mg to about 0.5 mg, or from about 0.1 mg to about 0.4 mg, or from about 0.1 mg to about 0.3 mg, or from about 0.1 mg to about 0.2 mg per dose of the composition. [0573] In some embodiments, the water-soluble polyanionic polymer may be present in a composition of the disclosure in a range of from about 0.1 mg to about 1.0 mg, or from about 0.1 mg to about 0.9 mg, or from about 0.1 mg to about 0.8 mg, or from about 0.1 mg to about 0.7 mg, or from 0.1 mg to about 0.6 mg, or from about 0.1 mg to about 0.5 mg per dose of the composition. [0574] In some embodiments, the water-soluble polyanionic polymer may be present in a composition of the disclosure in a range of from about 0.1 mg to about 0.5 mg, or from about 0.2 mg to about 0.5 mg, or from about 0.3 mg to about 0.5 mg, or from about 0.4 mg to about 0.5 mg per dose of the composition. [0575] In some embodiments, the water-soluble polyanionic polymer may be present in a composition of the disclosure at about 0.1 mg, 0.125, 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.5, 2.8, 3.0, 3.5, or at about 4.0 mg per dose of the composition. [0576] In some embodiments, the water-soluble polyanionic polymer may be present in a composition of the disclosure at about 0.1 mg, 0.125, 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 mg per dose of said composition. [0577] In some embodiments, the water-soluble polyanionic polymer may be present in a composition of the disclosure at about 0.1 mg, 0.125, 0.2, 0.25, 0.3, 0.4, or at about 0.5 mg per dose of said composition. [0578] In some embodiments, the water-soluble polyanionic polymer may be present in a composition of the disclosure at about 0.125 mg, at about 0.25 mg, or at about 0.5 mg per dose of said composition. Nucleic acid carrier [0579] In some embodiments, in a composition of the disclosure, the nucleic acid may be complexed with and/or at least partially encapsulated in the nucleic acid carrier. [0580] In some embodiments, a composition of the disclosure may be obtainable by a method comprising a step of encapsulating the nucleic acid in the nucleic acid carrier and obtaining at least partially encapsulated nucleic acid in said nucleic acid carrier and a step of mixing said nucleic acid carrier encapsulating said nucleic acid with the water-soluble polyanionic polymer. [0581] In some embodiments, an immunogenic composition of the disclosure may be obtainable by a process comprising at least the steps of: [0582] (a) formulating at least one nucleic acid encoding at least one antigen with at least one nucleic acid carrier, wherein the nucleic acid carrier comprises at least one cationic, or ionizable cationic, lipid, thus obtaining a first composition, and [0583] (b) formulating the first composition obtained in step (a) with at least one water- soluble polyanionic polymer. [0584] In some embodiments, step b) may be carried out by gently mixing the first composition obtained in step (a) with the water-soluble polyanionic polymer. As used herein “gently mixing” intends to refer to a mixing which does not create shear stress and does not structurally affect the nucleic acid carrier, and the other components of the composition. [0585] In some embodiments, the nucleic acid carrier may be a non-viral nucleic acid carrier. [0586] In some embodiments, the nucleic acid carrier may be selected in the group consisting of: lipid nanoparticles (LNP), solid lipid nanoparticles (SLNs), cationic nanoemulsions (CNEs), lipoplexes, cationic polymeric nanoparticles, immunostimulating complexes (ISCOMS), nanogels, inorganic nanoparticles, and lipidoid-coated iron oxide nanoparticles (LIONs). [0587] Nucleic acid carriers suitable for the disclosure are presented in Mobasher et al. (BBA - General Subjects, 1868 (2024) 130558; https://doi.org/10.1016/j.bbagen.2024.130558) [0588] In some embodiments, the nucleic acid carrier may be a CNE. [0589] In some embodiments, the nucleic acid carrier may be a LION. [0590] In some embodiments, the nucleic acid carrier may be an LNP. [0591] In some embodiments, the nucleic acid carrier comprises at least one cationic, or ionizable cationic. [0592] In some embodiments, the nucleic acid carrier may comprise at least one stealth lipid. [0593] In some embodiments, the nucleic acid carrier may comprise at least one structural lipid. [0594] In some embodiments, the nucleic acid carrier may comprise at least one helper lipid. [0595] In some embodiments, the nucleic acid carrier is an LNP, the LNP comprising, at least one cationic, or ionizable cationic, lipid, at least one stealth lipid, at least one structural lipid, and at least one helper lipid. LNPs [0596] The present disclosure also provides a composition comprising a lipid nanoparticle (LNP), wherein the LNP comprises a cationic, or ionizable cationic, lipid of the present disclosure. A cationic, or ionizable cationic, lipid, such as those described herein, affords a positively charged environment at low pH and facilitates efficient encapsulation of a negatively charged drug substance (e.g., mRNA) in the LNP. [0597] In some embodiments, the LNP may further comprise at least one of a structural lipid, a helper lipid, or a stealth lipid. In some embodiments, the LNP may comprise a cationic, or ionizable cationic, lipid and a structural lipid. In some embodiments, the LNP may comprise a cationic, or ionizable cationic, lipid and a helper lipid. In some embodiments, the LNP may comprise a cationic, or ionizable cationic, lipid and a stealth lipid. In some embodiments, the LNP may comprise a cationic, or ionizable cationic, lipid, a structural lipid, a helper lipid, and a stealth lipid. [0598] A lipid nanoparticle (LNP) encapsulating a nucleic acid, e.g., an mRNA, is provided. In some embodiments, a lipid nanoparticle suitable for use with the present disclosure may comprise one or more cationic, or ionizable cationic, lipids, one or more non- cationic lipids such as helper lipid and structural lipid (e.g., DSPC or DOPE and/or cholesterol), and one or more stealth lipid, such as PEG-modified lipids (e.g., DMG-PEG2K). [0599] A typical lipid nanoparticle for use with the disclosure may be composed of four lipid components: a cationic, or ionizable cationic, lipid (e.g., a sterol-based cationic lipid), a helper lipid or neutral lipid (e.g., DSPC, DOPE or DEPE), a structural lipid, e.g., a cholesterol- based lipid (e.g., cholesterol) and a stealth lipid, e.g. a PEG-modified lipid (e.g., DMG-PEG2K). [0600] The lipid nanoparticles for use in the disclosure can be prepared by various techniques which are presently known in the art. Such methods are described, e.g., in published U.S. Application No. US 2011/0244026, published U.S. Application No. US 2016/0038432, published U.S. Application No. US 2018/0153822, published U.S. Application No. US 2018/0125989 and published International Application No. WO 2021/016430, filed July 23, 2020, all of which are incorporated herein by reference. Lipid nanoparticles (LNPs) size and distribution [0601] In some embodiments, the majority of LNPs in a composition of the disclosure, i.e., greater than about 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% of the LNPs, have a mean diameter size of about 150 nm (e.g., about 145 nm, about 140 nm, about 135 nm, about 130 nm, about 125 nm, about 120 nm, about 115 nm, about 110 nm, about 105 nm, about 100 nm, about 95 nm, about 90 nm, about 85 nm, or about 80 nm). In some embodiments, the LNPs in a composition of the disclosure have a mean diameter size of about 150 nm or less (e.g., about 145 nm or less, about 140 nm or less, about 135 nm or less, about 130 nm or less, about 125 nm or less, about 120 nm or less, about 115 nm or less, about 110 nm or less, about 105 nm or less, about 100 nm or less, about 95 nm or less, about 90 nm or less, about 85 nm or less, or about 80 nm or less). [0602] In some embodiments, greater than about 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% of the LNPs in a composition provided by the present disclosure may have a mean diameter size ranging from about 40-90 nm (e.g., about 45-85 nm, about 50-80 nm, about 55-75 nm, about 60-70 nm). In some embodiments, the LNPs may have a mean diameter size ranging from about 40-90 nm (e.g., about 45-85 nm, about 50-80 nm, about 55- 75 nm, about 60-70 nm). Compositions with LNPs having a mean diameter size of about 50- 70 nm (e.g., 55-65 nm) may be particularly suitable for pulmonary delivery via nebulization. [0603] In some embodiments, the dispersity, or measure of heterogeneity in size of molecules (PDI or PI), of LNPs is less than about 0.5. [0604] The “polydispersity index” (PDI or PI) is a measurement of the homogeneous or heterogeneous size distribution of the individual lipid nanoparticles in a lipid nanoparticles mixture and indicates the breadth of the particle distribution in a mixture. The PI can be determined, for example, as described herein. [0605] In one embodiment, the polydispersity index of the nanoparticles described herein may be measured by dynamic light scattering. [0606] In some embodiments, the LNP may have a PDI of less than about 0.5. In some embodiments, the LNP may have a PDI of less than about 0.4. In some embodiments, the LNP may have a PDI of less than about 0.3. In some embodiments, the LNP may have a PDI of less than about 0.28. In some embodiments, the LNP may have a PDI of less than about 0.25. In some embodiments, the LNP may have a PDI of less than about 0.23. In some embodiments, the LNP may have a PDI of less than about 0.20. In some embodiments, the LNP may have a PDI of less than about 0.18. In some embodiments, the LNP may have a PDI of less than about 0.16. In some embodiments, the LNP may have a PDI of less than about 0.14. In some embodiments, the LNP may have a PDI of less than about 0.12. In some embodiments, the LNP may have a PDI of less than about 0.10. In some embodiments, the LNP may have a PDI of less than about 0.08. [0607] The LNPs may contain or encapsulate at least one nucleic acid. [0608] In such case, the LNPs may have a global surface charge which is the sum of the negative and positive electric charges at the surface of the particles, and which is represented by the zeta potential. The zeta potential is the potential difference between the dispersion medium and the stationary layer of fluid attached to the dispersed particle. Zeta potential is widely used for quantification of the magnitude of the electrical charge at the double layer. [0609] Zeta potential can be calculated using theoretical models and experimentally determined using electrophoretic mobility or dynamic electrophoretic mobility measurements. Electrophoresis may be used for estimating zeta potential of particulates. In practice, the zeta potential of a dispersion can be measured by applying an electric field across the dispersion. Particles within the dispersion with a zeta potential will migrate toward the electrode of opposite charge with a velocity proportional to the magnitude of the zeta potential. This velocity may be measured using the technique of the Laser Doppler Anemometer. The frequency shift or phase shift of an incident laser beam caused by these moving particles may be measured as the particle mobility, and this mobility may be converted to the zeta potential by inputting the dispersant viscosity and dielectric permittivity, and the application of the Smoluchowski theories. Electrophoretic velocity is proportional to electrophoretic mobility, which is the measurable parameter. There are several theories that link electrophoretic mobility with zeta potential. [0610] Suitable systems such as the NICOMP 380 ZLS system or the MALVERN NANOZS can be used for determining the zeta potential. Such systems usually measure the electrophoretic mobility and stability of charged particles in liquid suspension. These values may be a predictor of the repulsive forces being exerted by the particles in suspension and are directly related to the stability of the colloidal system. [0611] At pH neutral, the zeta potential of the lipid nanoparticles as disclosed herein may be close to neutral. [0612] In one advantage, to have a zeta potential close to zero facilitates particle mobility in the body, reduces opsonization and augment access to target tissues. [0613] In one embodiment, at pH from 6.0 to 7.5, the zeta potential of the lipid nanoparticles may be from about -3 mV to about +3 mV, for example from about -1 mV to about +1 mV, and for example from about -0.5 mV to about +0.5 mV. Cationic lipid [0614] In some embodiments, the cationic, or ionizable cationic, lipid may be biodegradable. [0615] In some embodiments, the cationic, or ionizable cationic, lipid may be not biodegradable. [0616] In some embodiments, the cationic, or ionizable cationic, lipid may be cleavable. [0617] In some embodiments, the cationic, or ionizable cationic, lipid may be not cleavable. [0618] In some embodiments, the cationic, or ionizable cationic, lipid may be selected in the group consisting of: 2,5-piperazinedione based lipids, dianhydrohexitol based lipids, 2- (4-(alkyldisulfaneyl)alkyl)piperazine-1-yl)alkyl alkanoate based lipids, (hydroxyalkyl) disubstituted amines based lipids, and benzene-1,3,5-tricarboxamide based lipids. [0619] In some embodiments, the cationic or ionizable cationic lipid may be a 2,5- piperazinedione based lipid. Exemplary 2,5-piperazinedione based lipids include OF-02, cKK- E10, cKK-E12 and lipids disclosed in WO 2013/063468, WO 2016/205691, and WO 2020/097384, which are incorporated herein by reference. [0620] In some embodiments, the cationic or ionizable cationic lipid may be a dianhydrohexitol based lipid. Exemplary dianhydrohexitol based lipids include IM-001, IS-001, and lipids disclosed in WO 2022/174048 and EP 23306049.0, which are incorporated herein by reference. [0621] In some embodiments, the cationic or ionizable cationic lipid may be a 2-(4- (alkyldisulfaneyl)alkyl)piperazine-1-yl)alkyl alkanoate based lipid. Exemplary 2-(4- (alkyldisulfaneyl)alkyl)piperazine-1-yl)alkyl alkanoate based lipids include GL-HEPES-E3-E12- DS-4-E10, GL-HEPES-E3-E10-DS-3-E18-1; GL-HEPES-E3-E12-DS-3-E14, and lipids disclosed in WO 2022/221688 and WO 2023/198857, which are incorporated herein by reference. [0622] In some embodiments, the cationic or ionizable cationic lipid may be (hydroxyalkyl) disubstituted amine based lipid. Exemplary (hydroxyalkyl) disubstituted amine based lipids include ALC-315 (also known as ALC-0315), SM-102, and lipids disclosed in WO 2017/049245 and WO 2018/078053, which are incorporated herein by reference. [0623] In some embodiments, the cationic or ionizable cationic lipid may be a benzene- 1,3,5-tricarboxamide based lipid. Exemplary benzene-1,3,5-tricarboxamide based lipids include FTT5, MVL5, and lipids disclosed in WO 2019/099501 and Ahmad et al., 2005, “New multivalent cationic lipids reveal bell curve for transfection efficiency versus membrane charge density: lipid-DNA complexes for gene delivery,” J. Gene Med., 7: 739-748, doi.org/10.1002/jgm.717, which is incorporated herein by reference. [0624] In some embodiments, the LNP may comprise a cationic lipid. [0625] In some embodiments, the LNP may comprise an ionizable cationic lipid. [0626] The cationic lipid may afford a positively charged environment at low pH to facilitate efficient encapsulation of the negatively charged nucleic acid, e.g., a mRNA. [0627] Various cationic lipids or ionizable cationic lipids which may be suitable for use in LNPs are known in the art. These include, for example, DOTAP (1,2-dioleyl-3- trimethylammonium propane), DODAP (1,2-dioleyl-3-dimethylammonium propane), DOTMA (N-[l-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride), DLinKC2DMA, DLin-KC2- DM, and C12-200. [0628] Exemplary cationic lipids suitable for use in the LNPs, compositions, pharmaceutical compositions and methods of the disclosure are described herein and may include, for instance, the cationic lipids as described in International Patent Publication WO 2010/144740, which is incorporated herein by reference. [0629] In some embodiments, the cationic lipid may be (6Z,9Z,28Z,31Z)- heptatriaconta-6,9,28,31-tetraen-19-yl 4-(dimethylamino) butanoate, having a compound structure of: [0630] [0631] or a pharmaceutically acceptable salt thereof. [0632] Other suitable cationic lipids may include ionizable cationic lipids as described in International Patent Publication WO 2013/149140, which is incorporated herein by reference. [0633] In some embodiments, the cationic lipid may be of one of the following formulas: , [0635] or a pharmaceutically acceptable salt thereof, wherein R₁ and R₂ are each independently selected from the group consisting of hydrogen, an optionally substituted, variably saturated or unsaturated C₁-C₂₀ alkyl and an optionally substituted, variably saturated or unsaturated C₆-C₂₀ acyl; wherein L₁ and L₂ are each independently selected from the group consisting of hydrogen, an optionally substituted C₁-C₃₀ alkyl, an optionally substituted variably unsaturated C₁-C₃₀ alkenyl, and an optionally substituted C₁-C₃₀ alkynyl; wherein m and o are each independently selected from the group consisting of zero and any positive integer (e.g., where m is three); and wherein n is zero or any positive integer (e.g., where n is one). [0636] In some embodiments, the cationic lipid may be (15Z, 18Z)-N,N-dimethyl-6- (9Z,12Z)-octadeca-9,12-dien-l-yl) tetracosa-15,18-dien-1-amine (“HGT5000”), having a compound structure of: [0639] or a pharmaceutically acceptable salt thereof. [0640] In some embodiments, the cationic lipid may be (15Z, 18Z)-N,N-dimethyl-6- ((9Z,12Z)-octadeca-9,12-dien-1-yl) tetracosa-4,15,18-trien-l-amine (“HGT5001”), having a compound structure of: [0641] [0642] (HGT-5001) [0643] or pharmaceutically acceptable salt thereof. [0644] In some embodiments, the cationic lipid may be (15Z,18Z)-N,N-dimethyl-6- ((9Z,12Z)-octadeca-9,12-dien-1-yl) tetracosa-5,15,18-trien- 1-amine (“HGT5002”), having a compound structure of: [0646] (HGT-5002) [0647] or a pharmaceutically acceptable salt thereof. [0648] Other suitable cationic lipids may be cationic lipids described as aminoalcohol lipidoids in International Patent Publication WO 2010/053572, which is incorporated herein by reference. [0649] In some embodiments, the cationic lipid may have a compound structure of: [0650] [0651] or a pharmaceutically acceptable salt thereof. [0652] Other suitable cationic lipids may include the cationic lipids as described in International Patent Publication WO 2016/118725, which is incorporated herein by reference. In some embodiments, a cationic lipid may have a compound structure of: [0653] [0654] and pharmaceutically acceptable salts thereof. [0655] Other suitable cationic lipids may include the cationic lipids as described in International Patent Publication WO 2016/118724, which is incorporated herein by reference. In some embodiments, the cationic lipid may have a compound structure of: [0656] [0657] or a pharmaceutically acceptable salt thereof. [0658] Other suitable cationic lipids may include a cationic lipid having the formula of 14,25-ditridecyl 15,18,21,24-tetraaza-octatriacontane, and pharmaceutically acceptable salts thereof. [0659] Other suitable cationic lipids may include the cationic lipids as described in J. McClellan, M. C. King, Cell 2010, 141, 210-217 and in Whitehead et al., Nature Communications (2014) 5:4277, which is incorporated herein by reference. [0660] In some embodiments, the cationic lipids may have a compound structure of: [0661] [0662] or a pharmaceutically acceptable salt thereof. [0663] Other suitable cationic lipids may include the cationic lipids as described in International Patent Publication WO 2015/199952, which is incorporated herein by reference. [0664] In some embodiments, the cationic lipid may have the compound structure: [0665] [0666] or a pharmaceutically acceptable salt thereof. [0667] In some embodiments, the cationic lipid may have the compound structure: [0668] [0669] or a pharmaceutically acceptable salt thereof. [0670] In some embodiments, the cationic lipid may have the compound structure: [0671] [0672] or a pharmaceutically acceptable salt thereof. [0673] In some embodiments, the cationic lipid may have the compound structure: [0674] [0675] or a pharmaceutically acceptable salt thereof. [0676] In some embodiments, the cationic lipid may have the compound structure: [0677] [0678] or a pharmaceutically acceptable salt thereof. [0679] In some embodiments, the cationic lipid may have the compound structure: [0681] or a pharmaceutically acceptable salt thereof. [0682] In some embodiments, the cationic lipid may have the compound structure: [0683] [0684] or a pharmaceutically acceptable salt thereof. [0685] In some embodiments, the cationic lipid may have the compound structure: [0686] [0687] or a pharmaceutically acceptable salt thereof. [0688] In some embodiments, the cationic lipid may have the compound structure: [0690] or a pharmaceutically acceptable salt thereof. [0691] In some embodiments, the cationic lipid may have the compound structure: [0692] [0693] or a pharmaceutically acceptable salt thereof. [0694] In some embodiments, the cationic lipid may have the compound structure: [0695] [0696] or a pharmaceutically acceptable salt thereof. [0697] In some embodiments, the cationic lipid may have the compound structure: [0698] [0699] or a pharmaceutically acceptable salt thereof. [0700] In some embodiments, the cationic lipid may have the compound structure: [0701] [0702] or a pharmaceutically acceptable salt thereof. [0703] Other suitable cationic lipids may include the cationic lipids as described in International Patent Publication WO 2017/004143, which is incorporated herein by reference. [0704] In some embodiments, the cationic lipid may have the compound structure: [0705] [0706] or a pharmaceutically acceptable salt thereof. [0707] In some embodiments, the cationic lipid may have the compound structure: [0708] [0709] or a pharmaceutically acceptable salt thereof. [0710] In some embodiments, the cationic lipid may have the compound structure: [0711] [0712] or a pharmaceutically acceptable salt thereof. [0713] In some embodiments, the cationic lipid may have the compound structure: [0714] [0715] or a pharmaceutically acceptable salt thereof. [0716] In some embodiments, the cationic lipid may have the compound structure: [0717] [0718] or a pharmaceutically acceptable salt thereof. [0719] In some embodiments, the cationic lipid may have the compound structure: [0720] [0721] or a pharmaceutically acceptable salt thereof. [0722] In some embodiments, the cationic lipid may have the compound structure: [0723] [0724] or a pharmaceutically acceptable salt thereof. [0725] In some embodiments, the cationic lipid may have the compound structure: [0726] [0727] or a pharmaceutically acceptable salt thereof. [0728] In some embodiments, the cationic lipid may have the compound structure: [0729] [0730] or a pharmaceutically acceptable salt thereof. [0731] In some embodiments, the cationic lipid may have the compound structure: [0732] [0733] or a pharmaceutically acceptable salt thereof. [0734] In some embodiments, the cationic lipid may have the compound structure: [0735] [0736] or a pharmaceutically acceptable salt thereof. [0737] In some embodiments, the cationic lipid may have the compound structure: [0739] or a pharmaceutically acceptable salt thereof. [0740] In some embodiments, the cationic lipid may have the compound structure: [0742] or a pharmaceutically acceptable salt thereof. [0743] In some embodiments, the cationic lipid may have the compound structure: [0744] [0745] or a pharmaceutically acceptable salt thereof. [0746] In some embodiments, the cationic lipid may have the compound structure: [0747] [0748] or a pharmaceutically acceptable salt thereof. [0749] In some embodiments, the cationic lipid may have the compound structure: [0751] or a pharmaceutically acceptable salt thereof. [0752] In some embodiments, the cationic lipid may have the compound structure: [0754] or a pharmaceutically acceptable salt thereof. [0755] Other suitable cationic lipids may include the cationic lipids as described in International Patent Publication WO 2017/075531, which is incorporated herein by reference. [0756] In some embodiments, the cationic lipid may be of the following formula: [0757] [0758] or a pharmaceutically acceptable salt thereof, wherein one of L¹ or L² is - O(C=O)-, -(C=O)O-, -C(=O)-, -O-, -S(O)_x, -S-S-, -C(=O)S-, -SC(=O)-, -NR^aC(=O)-, - C(=O)NR^a-, NR^aC(=O)NR^a-, -OC(=O)NR^a-, or -NR^aC(=O)O-; and the other of L¹ or L² is - O(C=O)-, -(C=O)O-, -C(=O)-, -O-, -S(O) _x, -S-S-, -C(=O)S-, SC(=O)-, -NR^aC(=O)-, - C(=O)NR^a-, ,NR^aC(=O)NR^a-, -OC(=O)NR^a- or -NR^aC(=O)O- or a direct bond; G¹ and G² are each independently unsubstituted C₁-C₁₂ alkylene or C₁-C₁₂ alkenylene; G³ is C₁-C₂₄ alkylene, C₁-C₂₄ alkenylene, C₃-C₈ cycloalkylene, C₃-C₈ cycloalkenylene; R^a is H or C₁-C₁₂ alkyl; R¹ and R² are each independently C₆-C₂₄ alkyl or C₆-C₂₄ alkenyl; R³ is H, OR⁵, CN, -C(=O)OR⁴, - OC(=O)R⁴ or -NR⁵ C(=O)R⁴; R⁴ is C₁-C₁₂ alkyl; R⁵ is H or C₁-C₆ alkyl; and x is 0, 1 or 2. [0759] Other suitable cationic lipids may include the cationic lipids as described in International Patent Publication WO 2017/117528, which is incorporated herein by reference. [0760] In some embodiments, the cationic lipid may have the compound structure: [0761] [0762] or a pharmaceutically acceptable salt thereof. [0763] In some embodiments, the cationic lipid may have the compound structure: [0764] [0765] or a pharmaceutically acceptable salt thereof. [0766] In some embodiments, the cationic lipid may have the compound structure: [0767] [0768] or a pharmaceutically acceptable salt thereof. [0769] Other suitable cationic lipids include the cationic lipids as described in International Patent Publication WO 2017/049245, which is incorporated herein by reference. [0770] In some embodiments, the cationic lipids may include a compound of one of the following formulas: , nd [0775] or a pharmaceutically acceptable salt thereof. For any one of these four formulas, R4 is independently selected from -(CH2)nQ and -(CH2) nCHQR; Q is selected from the group consisting of -OR, -OH, -O(CH₂)_nN(R)₂, -OC(O)R, -CX₃, -CN, -N(R)C(O)R, - N(H)C(O)R, -N(R)S(O)2R, -N(H)S(O)2R, -N(R)C(O)N(R)2, -N(H)C(O)N(R)2, -N(H)C(O)N(H)(R), -N(R)C(S)N(R)2, -N(H)C(S)N(R)2, -N(H)C(S)N(H)(R), and a heterocycle; and n is 1, 2, or 3. [0776] In some embodiments, the cationic lipid may have a compound structure of: [0777] [0778] or a pharmaceutically acceptable salt thereof. [0779] In some embodiments, the cationic lipid may have a compound structure of: [0780] [0781] or a pharmaceutically acceptable salt thereof. [0782] In some embodiments, the cationic lipid may have a compound structure of: [0784] or a pharmaceutically acceptable salt thereof. [0785] In some embodiments, the cationic lipid may have a compound structure of: [0787] or a pharmaceutically acceptable salt thereof. [0788] Other suitable cationic lipids may include the cationic lipids as described in International Patent Publication WO 2017/173054 and WO 2015/095340, each of which is incorporated herein by reference. [0789] In some embodiments, the cationic lipid may have a compound structure of: [0790] [0791] or a pharmaceutically acceptable salt thereof. [0792] In some embodiments, the cationic lipid may have a compound structure of: [0793] [0794] or a pharmaceutically acceptable salt thereof. [0795] In some embodiments, the cationic lipid may have a compound structure of: [0796] [0797] or a pharmaceutically acceptable salt thereof. [0798] In some embodiments, the cationic lipid may have a compound structure of: [0799] [0800] or a pharmaceutically acceptable salt thereof. [0801] Other suitable cationic lipids may include cationic lipids as described in published International Application No. WO 2022/066678, filed on September 22, 2021, which is incorporated herein by reference. [0802] In some embodiments, the cationic lipid may have a compound structure of: [0804] (GL-TES-SA-DME-E18-2) or a pharmaceutically acceptable salt thereof. [0805] In some embodiments, the cationic lipid may have a compound structure of: [0806] [0807] (GL-TES-SA-DMP-E18-2) or a pharmaceutically acceptable salt thereof. [0808] Other suitable cationic lipids may include cationic lipids as described in published International Application No. WO 2021/202694, filed on March 31, 2021, which is incorporated herein by reference. [0809] In some embodiments, the cationic lipid may have a compound structure of: [0811] (SY-3-E14-DMAPr) or a pharmaceutically acceptable salt thereof. [0812] Other suitable cationic lipids may include cationic lipids as described in published International Application No. WO 2022/066916, filed on September 23, 2021, which is incorporated herein by reference. [0813] In some embodiments, the cationic lipid may have a compound structure of: [0815] (HEP-E3-E10) or a pharmaceutically acceptable salt thereof. [0816] In some embodiments, the cationic lipid may have a compound structure of: [0818] (HEP-E4-E10) or a pharmaceutically acceptable salt thereof. [0819] Other suitable cationic lipids may include cationic lipids as described in published International Application No. WO 2020/257716, filed on June 19, 2020, which is incorporated herein by reference. [0820] In some embodiments, the cationic lipid may have a compound structure according to the following formula: , [0822] or a pharmaceutically acceptable salt thereof, wherein each of R², R³, and R⁴ is independently C6-C30 alkyl, C6-C30 alkenyl, or C6-C30 alkynyl; L¹ is C1–C30 alkylene; C2–C30 alkenylene; or C2–C30 alkynylene and B¹ is an ionizable nitrogen-containing group. In embodiments, L¹ is C1–C10 alkylene. [0823] In some embodiments, L¹ is unsubstituted C1–C10 alkylene. In embodiments, L¹ is (CH2)2, (CH2)3, (CH2)4, or (CH2)5. [0824] In some embodiments, L¹ is (CH2), (CH2)6, (CH2)7, (CH2)8, (CH2)9, or (CH2)10. In some embodiments, B¹ is independently NH2, guanidine, amidine, a mono- or dialkylamine, 5- to 6-membered nitrogen-containing heterocycloalkyl, or 5- to 6-membered nitrogen-containing heteroaryl. In embodiments, B¹ is , . [0826] In some embodiments, B¹ is . [0827] In some embodiments, each of R², R³, and R⁴ is independently unsubstituted linear C₆-C₂₂ alkyl, unsubstituted linear C₆-C₂₂ alkenyl, unsubstituted linear C₆-C₂₂ alkynyl, unsubstituted branched C₆-C₂₂ alkyl, unsubstituted branched C₆-C₂₂ alkenyl, or unsubstituted branched C₆-C₂₂ alkynyl. In embodiments, each of R², R³, and R⁴ is unsubstituted C₆-C₂₂ alkyl. [0828] In some embodiments, each of R², R³, and R⁴ is -C₆H₁₃, -C₇H₁₅, -C₈H₁₇, -C₉H₁₉, -C₁₀H₂₁, -C₁₁H₂₃, -C₁₂H₂₅, -C₁₃H₂₇, -C₁₄H₂₉, -C₁₅H₃₁, -C₁₆H₃₃, -C₁₇H₃₅, -C₁₈H₃₇, -C₁₉H₃₉, -C₂₀H₄₁, -C₂₁H₄₃, -C₂₂H₄₅, -C₂₃H₄₇, -C₂₄H₄₉, or -C₂₅H₅₁. [0829] In some embodiments, each of R², R³, and R⁴ is independently C₆-C₁₂ alkyl substituted by –O(CO)R⁵ or C(O)OR⁵, wherein R⁵ is unsubstituted C₆-C₁₄ alkyl. [0830] In some embodiments, each of R², R³, and R⁴ is unsubstituted C₆-C₂₂ alkenyl. [0831] In some embodiments, each of R², R³, and R⁴ is -(CH₂)₄CH=CH₂, - (CH₂)₅CH=CH₂, -(CH₂)₆CH=CH₂, -(CH₂)₇CH=CH₂, -(CH₂)₈CH=CH₂, -(CH₂)₉CH=CH₂, - (CH₂)₁₀CH=CH₂, -(CH₂)₁₁CH=CH₂, -(CH₂)₁₂CH=CH₂, -(CH₂)₁₃CH=CH₂, -(CH₂)₁₄CH=CH₂, - (CH₂)₁₅CH=CH₂, -(CH₂)₁₆CH=CH₂, -(CH₂)₁₇CH=CH₂, -(CH₂)₁₈CH=CH₂, - (CH₂)₇CH=CH(CH₂)₃CH₃, -(CH₂)₇CH=CH(CH₂)₅CH₃, -(CH₂)₄CH=CH(CH₂)₈CH₃, - (CH₂)₇CH=CH(CH₂)₇CH₃, -(CH₂)₆CH=CHCH₂CH=CH(CH₂)₄CH₃, - (CH₂)₇CH=CHCH₂CH=CH(CH₂)₄CH₃, -(CH₂)₇CH=CHCH₂CH=CHCH₂CH=CHCH₂CH₃, - (CH₂)₃CH=CHCH₂CH=CHCH₂CH=CHCH₂CH=CH(CH₂)₄CH₃, -(CH₂)₃CH=CHCH₂CH=CHCH₂CH=CHCH₂CH=CHCH₂CH=CHCH₂CH₃, -(CH₂)₁₁CH=CH(CH₂)₇CH₃, or -(CH2)2CH=CHCH2CH=CHCH2CH=CHCH2CH=CHCH2CH=CHCH2CH=CHCH2CH3. [0832] In some embodiments, said C6-C22 alkenyl is a monoalkenyl, a dienyl, or a trienyl. In embodiments, each of R², R³, and R⁴ is ^{; ; ; ; ; ; ; ; ;} ; or . [0833] In some embodiments, the cationic lipid may have a compound structure of: [0835] (TL1-01D-DMA) [0836] or a pharmaceutically acceptable salt thereof. [0837] In some embodiments, the cationic lipid may have a compound structure of: [0838] [0839] (TL1-04D-DMA) [0840] or a pharmaceutically acceptable salt thereof. [0841] In some embodiments, the cationic lipid may have a compound structure of: [0842] [0843] (TL1-08D-DMA) [0844] or a pharmaceutically acceptable salt thereof. [0845] In some embodiments, the cationic lipid may have a compound structure of: [0848] or a pharmaceutically acceptable salt thereof. [0849] Other suitable cationic lipids include cleavable cationic lipids as described in International Patent Publication WO 2012/170889, which is incorporated herein by reference. [0850] In some embodiments, the LNPs of the present disclosure may include a cationic lipid of the following formula: [0851] , [0852] wherein R₁ is selected from the group consisting of imidazole, guanidinium, amino, imine, enamine, an optionally-substituted alkyl amino (e.g., an alkyl amino such as dimethylamino) and pyridyl; wherein R2 is selected from the group consisting of one of the following two formulas: [0853] [0854] and wherein R3 and R4 are each independently selected from the group consisting of an optionally substituted, variably saturated or unsaturated C6–C20 alkyl and an optionally substituted, variably saturated or unsaturated C6–C20 acyl; and wherein n is zero or any positive integer (e.g., one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty or more). [0855] In some embodiments, the cationic lipid may be “HGT4001”, having a compound structure of: [0856] [0857] (HGT4001) [0858] or a pharmaceutically acceptable salt thereof. [0859] In some embodiments, the cationic lipid may be “HGT4002”, having a compound structure of: [0861] (HGT4002) [0862] or a pharmaceutically acceptable salt thereof. [0863] In some embodiments, the cationic lipid may be “HGT4003,” having a compound structure of: [0864] [0865] (HGT4003) [0866] or a pharmaceutically acceptable salt thereof. [0867] In some embodiments, the cationic lipid may be “HGT4004,” having a compound structure of: [0870] or a pharmaceutically acceptable salt thereof. [0871] In some embodiments, the cationic lipid may be “HGT4005,” having a compound structure of: [0872] [0873] (HGT4005) [0874] or a pharmaceutically acceptable salt thereof. [0875] Other suitable cationic lipids may include cleavable cationic lipids as described in International Patent Publication WO 2019/222424, incorporated herein by reference. [0876] In some embodiments, the cationic lipid may be a cationic lipid that is any of general formulas or any of structures (1a)–(21a) and (1b) – (21b) and (22)–(237) described in International Patent Publication WO 2019/222424. [0877] In some embodiments, the cationic lipid may be a cationic lipid that has a structure according to Formula (I’), [0878] , [0879] wherein: [0880] R^X is independently -H, -L¹-R¹, or –L^5A-L^5B-B’; [0881] each of L¹, L², and L³ is independently a covalent bond, -C(O)-, -C(O)O-, - C(O)S-, or -C(O)NR^L-; [0882] each L^4A and L^5A is independently -C(O)-, -C(O)O-, or -C(O)NR^L-; [0883] each L^4B and L^5B is independently C1-C20 alkylene; C2-C20 alkenylene; or C2-C20 alkynylene; [0884] each B and B’ is NR⁴R⁵ or a 5- to 10-membered nitrogen-containing heteroaryl; [0885] each R¹, R², and R³ is independently C6-C30 alkyl, C6-C30 alkenyl, or C6-C30 alkynyl; [0886] each R⁴ and R⁵ is independently hydrogen, C₁-C₁₀ alkyl; C₂-C₁₀ alkenyl; or C₂- C₁₀ alkynyl; and [0887] each R^L is independently hydrogen, C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, or C₂-C₂₀ alkynyl. [0888] In some embodiments, the cationic lipid may be a cationic lipid that is Compound (139) of International Patent Publication No. WO 2019/222424, having a compound structure of: [0889] (“18:1 Carbon tail-ribose lipid”). [0890] In some embodiments, the cationic lipid may be a cationic lipid that is RL3-DMA- 07D having a compound structure of: [0893] or a pharmaceutically acceptable salt thereof. [0894] In some embodiments, the cationic lipid may be a cationic lipid that is RL2-DMP- 07D having a compound structure of: (RL2-DMP-07D) [0896] or a pharmaceutically acceptable salt thereof. [0897] Other suitable cationic lipids may include the cationic lipids as described in International Patent Publications WO 2013/063468 and WO 2016/205691, each of which are incorporated herein by reference. [0898] In some embodiments, the cationic lipid may be a cationic lipid of the following formula: [0899] [0900] or pharmaceutically acceptable salt thereof, wherein each instance of R^L is independently optionally substituted C₆-C₄₀ alkenyl. [0901] In some embodiments, the cationic lipid may have a compound structure of: [0903] or a pharmaceutically acceptable salt thereof. [0904] In some embodiments, the cationic lipid may have a compound structure of: [0906] or a pharmaceutically acceptable salt thereof. [0907] In some embodiments, the cationic lipid may be a ionizable cationic lipid having a compound structure of: [0908] [0909] or a pharmaceutically acceptable salt thereof. [0910] In some embodiments, the cationic lipid may be an ionizable cationic lipid having a compound structure of: [0911] [0913] In some embodiments, the cationic lipid may have a compound structure of: [0914] [0915] or a pharmaceutically acceptable salt thereof. [0916] In some embodiments, the cationic lipid may have a compound structure of: [0918] or a pharmaceutically acceptable salt thereof. [0919] Other suitable cationic lipids include the cationic lipids as described in International Patent Publication WO 2015/184256, which is incorporated herein by reference. [0920] In some embodiments, the cationic lipid may be a cationic lipid of the following formula: [0921] [0922] or a pharmaceutically acceptable salt thereof, wherein each X independently is O or S; each Y independently is O or S; each m independently is 0 to 20; each n independently is 1 to 6; each RA is independently hydrogen, optionally substituted C1-50 alkyl, optionally substituted C2-50 alkenyl, optionally substituted C2-50 alkynyl, optionally substituted C3-10 carbocyclyl, optionally substituted 3-14 membered heterocyclyl, optionally substituted C6-14 aryl, optionally substituted 5-14 membered heteroaryl or halogen; and each RB is independently hydrogen, optionally substituted C1-50 alkyl, optionally substituted C2-50 alkenyl, optionally substituted C2-50 alkynyl, optionally substituted C3-10 carbocyclyl, optionally substituted 3-14 membered heterocyclyl, optionally substituted C6-14 aryl, optionally substituted 5-14 membered heteroaryl or halogen. [0923] In some embodiments, the cationic lipid may be a cationic lipid, “Target 23”, having a compound structure of: [0924] [0925] (Target 23) [0926] or a pharmaceutically acceptable salt thereof. [0927] Other suitable cationic lipids include the cationic lipids as described in International Patent Publication WO 2016/004202, which is incorporated herein by reference. [0928] In some embodiments, the cationic lipid may have the compound structure: [0931] or a pharmaceutically acceptable salt thereof. [0932] In some embodiments, the cationic lipid may have the compound structure: [0934] or a pharmaceutically acceptable salt thereof. [0935] In some embodiments, the cationic lipid may have the compound structure: [0937] or a pharmaceutically acceptable salt thereof. [0938] Other suitable cationic lipids include cationic lipids as described in International Patent Publication WO 2020/097384, which is incorporated herein by reference. [0939] In some embodiments, the cationic lipid may be a cationic lipid of the following formula: , [0942] or a pharmaceutically acceptable salt thereof, wherein each R¹ and R² is independently H or C1-C6 aliphatic; each m is independently an integer having a value of 1 to 4; each A is independently a covalent bond or arylene; each L¹ is independently an ester, thioester, disulfide, or anhydride group; each L² is independently C2-C10 aliphatic; each X¹ is independently H or OH; and each R³ is independently C6-C20 aliphatic. [0943] In some embodiments, the cationic lipid may be a cationic lipid of the following formula: [0944] [0945] (Compound 6, cDD-TE-4-E12) [0946] or a pharmaceutically acceptable salt thereof. [0947] In some embodiments, the cationic lipid may be a cationic lipid of the following formula: [0950] or a pharmaceutically acceptable salt thereof. [0951] In some embodiments, the cationic lipid may be a cationic lipid of the following formula: (Compound 125, cHse-E-3-E12) [0952] or a pharmaceutically acceptable salt thereof. [0953] In some embodiments, the cationic lipid may be GL-HEPES-E3-E10-DS-3-E18- 1 (2-(4-(2-((3-(Bis((Z)-2-hydroxyoctadec-9-en-1-yl)amino)propyl)disulfaneyl)ethyl)piperazin-1- yl)ethyl 4-(bis(2-hydroxydecyl)amino)butanoate), which is a HEPES-based disulfide cationic lipid with a piperazine core, having the Formula III: [0956] In some embodiments, the cationic lipid may be GL-HEPES-E3-E12-DS-4-E10 (2-(4-(2-((3-(bis(2-hydroxydecyl)amino)butyl)disulfaneyl)ethyl)piperazin-1-yl)ethyl 4-(bis(2- hydroxydodecyl)amino)butanoate), which is a HEPES-based disulfide cationic lipid with a piperazine core, having the Formula IV: [0957] [0958] Formula (IV) [0959] In some embodiments, the cationic lipid may be GL-HEPES-E3-E12-DS-3-E14 (2-(4-(2-((3-(Bis(2-hydroxytetradecyl)amino)propyl)disulfaneyl)ethyl)piperazin-1-yl)ethyl 4- (bis(2-hydroxydodecyl)amino)butanoate), which is a HEPES-based disulfide cationic lipid with a piperazine core, having the Formula V: [0962] In some embodiments, the cationic lipids GL-HEPES-E3-E10-DS-3-E18-1 (III), GL-HEPES-E3-E12-DS-4-E10 (IV), and GL-HEPES-E3-E12-DS-3-E14 (V) can be synthesized according to the general procedure set out in Scheme 1: [0963] Scheme 1: General Synthetic Scheme for Lipids of Formulas (III), (IV), and (V) [0964] In some embodiments, the cationic lipid may be MC3, having the Formula VI: [0965] [0966] Formula (VI) [0967] In some embodiments, the cationic lipid may be SM-102 (9-heptadecanyl 8-{(2- hydroxyethyl)[6-oxo-6-(undecyloxy)hexyl]amino}octanoate), having the Formula VII: [0968] [0969] [0970] [0971] In some embodiments, the cationic lipid may be ALC-0315 [(4- hydroxybutyl)azanediyl]di(hexane-6,1-diyl) bis(2-hexyldecanoate), having the Formula VIII: [0972] [0973] Formula (VIII) [0974] In some embodiments, the cationic lipid may be cOrn-EE1, having the Formula [0976] Formula (IX) [0977] In some embodiments, the cationic lipid may be selected from the group consisting of cKK-E10; OF-02; [(6Z,9Z,28Z,31Z)-heptatriaconta-6,9,28,31-tetraen-19-yl] 4- (dimethylamino)butanoate (D-Lin-MC3-DMA or MC3); 2,2-dilinoleyl-4-dimethylaminoethyl- [1,3]-dioxolane (dLin-KC2-DMA); 1,2-dilinoleyloxy-N,N-dimethyl-3-aminopropane (dLin-DMA); di((Z)-non-2-en-1-yl) 9-((4-(dimethylamino)butanoyl)oxy)heptadecanedioate (L319); 9- heptadecanyl 8-{(2-hydroxyethyl)[6-oxo-6-(undecyloxy)hexyl]amino}octanoate (SM-102); [(4- hydroxybutyl)azanediyl]di(hexane-6,1-diyl) bis(2-hexyldecanoate) (ALC-0315); [3- (dimethylamino)-2-[(Z)-octadec-9-enoyl]oxypropyl] (Z)-octadec-9-enoate (DODAP); 2,5-bis(3- aminopropylamino)-N-[2-[di(heptadecyl)amino]-2-oxoethyl]pentanamide (DOGS); [(3S,8S,9S,10R,13R,14S,17R)-10,13-dimethyl-17-[(2R)-6-methylheptan-2-yl]- 2,3,4,7,8,9,11,12,14,15,16,17-dodecahydro-1H-cyclopenta[a]phenanthren-3-yl] N-[2- (dimethylamino)ethyl]carbamate (DC-Chol); tetrakis(8-methylnonyl) 3,3′,3″,3‴- (((methylazanediyl) bis(propane-3,1 diyl))bis (azanetriyl))tetrapropionate (306Oi10); decyl (2- (dioctylammonio)ethyl) phosphate (9A1P9); ethyl 5,5-di((Z)-heptadec-8-en-1-yl)-1-(3- (pyrrolidin-1-yl)propyl)-2,5-dihydro-1H-imidazole-2-carboxylate (A2-Iso5-2DC18); bis(2- (dodecyldisulfanyl)ethyl) 3,3′-((3-methyl-9-oxo-10-oxa-13,14-dithia-3,6- diazahexacosyl)azanediyl)dipropionate (BAME-O16B); 1,1′-((2-(4-(2-((2-(bis(2- hydroxydodecyl)amino)ethyl) (2-hydroxydodecyl)amino)ethyl) piperazin-1-yl)ethyl)azanediyl) bis(dodecan-2-ol) (C12-200); 3,6-bis(4-(bis(2-hydroxydodecyl)amino)butyl)piperazine-2,5- dione (cKK-E12); hexa(octan-3-yl) 9,9′,9″,9‴,9″″,9‴″- ((((benzene-1,3,5- tricarbonyl)yris(azanediyl)) tris (propane-3,1-diyl)) tris(azanetriyl))hexanonanoate (FTT5); (((3,6-dioxopiperazine-2,5-diyl)bis(butane-4, 1-diyl))bis(azanetriyl))tetrakis(ethane-2,1-diyl) (9Z,9′Z,9″Z,9‴Z,12Z,12′Z,12″Z,12‴Z)-tetrakis (octadeca-9,12-dienoate) (OF-Deg-Lin); TT3; N1,N3,N5-tris(3-(didodecylamino)propyl)benzene-1,3,5-tricarboxamide; N1-[2-((1S)-1- [(3-aminopropyl)amino]-4-[di(3-aminopropyl)amino]butylcarboxamido)ethyl]-3,4-di[oleyloxy]- benzamide (MVL5); heptadecan-9-yl 8-((2-hydroxyethyl)(8-(nonyloxy)-8- oxooctyl)amino)octanoate (Lipid 5); GL-HEPES-E3-E10-DS-3-E18-1; GL-HEPES-E3-E12- DS-4-E10; GL-HEPES-E3-E12-DS-3-E14; cOrn-EE1; MC3; IM-001; IS-001; and combinations thereof. [0978] In some embodiments, the cationic lipid may be IM-001, having the Formula X (EP23306049.0): [0979] Formula (X) [0980] The cationic lipid IM-001 (X) can be synthesized according to the general procedure set out in Scheme 2: [0981] Scheme 2: General Synthetic Scheme for Lipid of Formula (X) IM-001 [0982] In some embodiments, the cationic lipid is IS-001, having the Formula XI (EP23306049.0): [0983] Formula (XI) [0984] The cationic lipid IS-001 (XI) can be synthesized according to the general procedure set out in Scheme 3: [0985] Scheme 3: General Synthetic Scheme for Lipid of Formula (XI) [0987] In some embodiments, the cationic lipid may be, N-[l-(2,3-dioleyloxy)propyl]- N,N,N-trimethylammonium chloride (“DOTMA”). (Feigner et al. (Proc. Nat’l Acad. Sci.84, 7413 (1987); U.S. Pat. No. 4,897,355, which is incorporated herein by reference). Other cationic lipids suitable for the present disclosure include, for example, 5- carboxyspermylglycinedioctadecylamide (“DOGS”); 2,3-dioleyloxy-N-[2(spermine- carboxamido)ethyl]-N,N-dimethyl-l-propanaminium (“DOSPA”) (Behr et al. Proc. Nat.’l Acad. Sci. 86, 6982 (1989), U.S. Pat. No. 5,171,678; U.S. Pat. No. 5,334,761); 1,2-Dioleoyl-3- Dimethylammonium-Propane (“DODAP”); 1,2-Dioleoyl-3-Trimethylammonium-Propane (“DOTAP”). [0988] Additional exemplary cationic lipids suitable for the present disclosure may also include: 1,2-distearyloxy-N,N-dimethyl-3-aminopropane (“DSDMA”); 1,2-dioleyloxy-N,N- dimethyl-3-aminopropane (“DODMA”); 1,2-dilinoleyloxy-N,N-dimethyl-3-aminopropane (“DLinDMA”); 1,2-dilinolenyloxy-N,N-dimethyl-3-aminopropane (“DLenDMA”); N-dioleyl-N,N- dimethylammonium chloride (“DODAC”); N,N-distearyl-N,N-dimethylammonium bromide (“DDAB”); N-(1,2-dimyristyloxyprop-3-yl)-N,N-dimethyl-N-hydroxyethyl ammonium bromide (“DMRIE”); 3-dimethylamino-2-(cholest-5-en-3-beta-oxybutan-4-oxy)-l-(cis,cis-9,12- octadecadienoxy)propane (“CLinDMA”); 2-[5’-(cholest-5-en-3-beta-oxy)-3’-oxapentoxy)-3- dimethy l-l-(cis,cis-9’, l-2’-octadecadienoxy)propane (“CpLinDMA”); N,N-dimethyl-3,4- dioleyloxybenzylamine (“DMOBA”); 1,2-N,N’-dioleylcarbamyl-3-dimethylaminopropane (“DOcarbDAP”); 2,3-Dilinoleoyloxy-Ν,Ν-dimethylpropylamine (“DLinDAP”); 1,2-N,N’- Dilinoleylcarbamyl-3-dimethylaminopropane (“DLincarbDAP”); 1,2-Dilinoleoylcarbamyl-3- dimethylaminopropane (“DLinCDAP”); 2,2-dilinoleyl-4-dimethylaminomethyl-[l,3]-dioxolane (“DLin-K-DMA”); 2-((8-[(3P)-cholest-5-en-3-yloxy]octyl)oxy)-N, N-dimethyl-3-[(9Z, 12Z)- octadeca-9, 12-dien-1 -yloxy]propane-1-amine (“Octyl-CLinDMA”); (2R)-2-((8-[(3beta)- cholest-5-en-3-yloxy]octyl)oxy)-N, N-dimethyl-3-[(9Z, 12Z)-octadeca-9, 12-dien-1- yloxy]propan-1-amine (“Octyl-CLinDMA (2R)”); (2S)-2-((8-[(3P)-cholest-5-en-3- yloxy]octyl)oxy)-N, fsl-dimethyh3-[(9Z, 12Z)-octadeca-9, 12-dien-1 -yloxy]propan-1-amine (“Octyl-CLinDMA (2S)”); 2,2-dilinoleyl-4-dimethylaminoethyl-[l,3]-dioxolane (“DLin-K-XTC2- DMA”); and 2-(2,2-di((9Z,12Z)-octadeca-9,l 2-dien- 1-yl)-l ,3-dioxolan-4-yl)-N,N- dimethylethanamine (“DLin-KC2-DMA”) (see, WO 2010/042877, which is incorporated herein by reference; Semple et al., Nature Biotech.28: 172-176 (2010)). (Heyes, J., et al., J Controlled Release 107: 276-287 (2005); Morrissey, DV., et al., Nat. Biotechnol.23(8): 1003-1007 (2005); International Patent Publication WO 2005/121348). In some embodiments, one or more of the cationic lipids comprise at least one of an imidazole, dialkylamino, or guanidinium moiety. [0989] In some embodiments, one or more cationic lipids suitable for the present disclosure may include 2,2-Dilinoley1-4-dimethylaminoethy1-[1,3]-dioxolane (“XTC”); (3aR,5s,6aS)-N,N-dimethyl-2,2-di((9Z,12Z)-octadeca-9,12-dienyl)tetrahydro-3aH- cyclopenta[d] [1,3]dioxol-5-amine (“ALNY-100”) and/or 4,7,13-tris(3-oxo-3- (undecylamino)propyl)-N1,N16-diundecyl-4,7,10,13-tetraazahexadecane-1,16-diamide (“NC98-5”). [0990] In some embodiments, the cationic, or ionizable cationic, lipid may be selected from the group consisting of: cKK-E10; OF-02; [(6Z,9Z,28Z,31Z)-heptatriaconta-6,9,28,31- tetraen-19-yl] 4-(dimethylamino)butanoate (D-Lin-MC3-DMA); 2,2-dilinoleyl-4- dimethylaminoethyl-[1,3]-dioxolane (dLin-KC2-DMA); 1,2-dilinoleyloxy-N,N-dimethyl-3- aminopropane (dLin-DMA); di((Z)-non-2-en-1-yl) 9-((4- (dimethylamino)butanoyl)oxy)heptadecanedioate (L319); 9-heptadecanyl 8-{(2- hydroxyethyl)[6-oxo-6-(undecyloxy)hexyl]amino}octanoate (SM-102); [(4- hydroxybutyl)azanediyl]di(hexane-6,1-diyl) bis(2-hexyldecanoate) (ALC-0315); [3- (dimethylamino)-2-[(Z)-octadec-9-enoyl]oxypropyl] (Z)-octadec-9-enoate (DODAP); 2,5-bis(3- aminopropylamino)-N-[2-[di(heptadecyl)amino]-2-oxoethyl]pentanamide (DOGS); [(3S,8S,9S,10R,13R,14S,17R)-10,13-dimethyl-17-[(2R)-6-methylheptan-2-yl]- 2,3,4,7,8,9,11,12,14,15,16,17-dodecahydro-1H-cyclopenta[a]phenanthren-3-yl] N-[2- (dimethylamino)ethyl]carbamate (DC-Chol); tetrakis(8-methylnonyl) 3,3′,3″,3‴- (((methylazanediyl) bis(propane-3,1 diyl))bis (azanetriyl))tetrapropionate (306Oi10); decyl (2- (dioctylammonio)ethyl) phosphate (9A1P9); ethyl 5,5-di((Z)-heptadec-8-en-1-yl)-1-(3- (pyrrolidin-1-yl)propyl)-2,5-dihydro-1H-imidazole-2-carboxylate (A2-Iso5-2DC18); bis(2- (dodecyldisulfanyl)ethyl) 3,3′-((3-methyl-9-oxo-10-oxa-13,14-dithia-3,6- diazahexacosyl)azanediyl)dipropionate (BAME-O16B); 1,1′-((2-(4-(2-((2-(bis(2- hydroxydodecyl)amino)ethyl) (2-hydroxydodecyl)amino)ethyl) piperazin-1-yl)ethyl)azanediyl) bis(dodecan-2-ol) (C12-200); 3,6-bis(4-(bis(2-hydroxydodecyl)amino)butyl)piperazine-2,5- dione (cKK-E12); hexa(octan-3-yl) 9,9′,9″,9‴,9″″,9‴″- ((((benzene-1,3,5- tricarbonyl)yris(azanediyl)) tris (propane-3,1-diyl)) tris(azanetriyl))hexanonanoate (FTT5); (((3,6-dioxopiperazine-2,5-diyl)bis(butane-4, 1-diyl))bis(azanetriyl))tetrakis(ethane-2,1-diyl) (9Z,9′Z,9″Z,9‴Z,12Z,12′Z,12″Z,12‴Z)-tetrakis (octadeca-9,12-dienoate) (OF-Deg-Lin); TT3; N1,N3,N5-tris(3-(didodecylamino)propyl)benzene-1,3,5-tricarboxamide; N1-[2-((1S)-1- [(3-aminopropyl)amino]-4-[di(3-aminopropyl)amino]butylcarboxamido)ethyl]-3,4-di[oleyloxy]- benzamide (MVL5); heptadecan-9-yl 8-((2-hydroxyethyl)(8-(nonyloxy)-8- oxooctyl)amino)octanoate (Lipid 5); GL-HEPES-E3-E10-DS-3-E18-1; GL-HEPES-E3-E12- DS-4-E10; GL-HEPES-E3-E12-DS-3-E14; cOrn-EE1; MC3; IM-001; IS-001; and combinations thereof [0991] In some embodiments, the cationic, or ionizable cationic, lipid may be selected from the group consisting of: OF-02, cKK-E10, GL-HEPES-E3-E10-DS-3-E18-1, GL-HEPES- E3-E12-DS-4-E10, GL-HEPES-E3-E12-DS-3-E14, IM-001, IS-001, ALC-0315, SM-102, MC3 and combination thereof. [0992] In some embodiments, the cationic, or ionizable cationic, lipid may be selected from the group consisting of: OF-02, cKK-E10, GL-HEPES-E3-E12-DS-4-E10, IM-001, IS-001, ALC-0315, SM-102, MC3, and combination thereof. [0993] In some embodiments, the cationic, or ionizable cationic, lipid may be OF-02. [0994] In some embodiments, the cationic, or ionizable cationic, lipid may be GL- HEPES-E3-E12-DS-4-E10. [0995] In some embodiments, the cationic, or ionizable cationic, lipid may be ALC- 0315. [0996] In some embodiments, the cationic, or ionizable cationic, lipid may be SM-102. [0997] In some embodiments, the cationic, or ionizable cationic, lipid may be MC3. [0998] In some embodiments, the LNPs of the present disclosure may include one or more cationic, or ionizable cationic, lipids that constitute at least about 5%, 10%, 20%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%, measured by weight, of the total lipid content in the LNP, e.g., a lipid nanoparticle. [0999] In some embodiments, the LNPs of the present disclosure may include one or more cationic, or ionizable cationic, lipids that constitute at least about 5%, 10%, 20%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%, measured as a mol %, of the total lipid content in the LNP, e.g., a lipid nanoparticle. [1000] In some embodiments, the LNPs of the present disclosure may include one or more cationic, or ionizable cationic, lipids that constitute about 30-70% (e.g., about 30-65%, about 30-60%, about 30-55%, about 30-50%, about 30-45%, about 30-40%, about 35-50%, about 35-45%, or about 35-40%), measured by weight, of the total lipid content in the LNP, e.g., a lipid nanoparticle. [1001] In some embodiments, the LNPs of the present disclosure may include one or more cationic, or ionizable cationic, lipids that constitute about 30-70 % (e.g., about 30-65%, about 30-60%, about 30-55%, about 30-50%, about 30-45%, about 30-40%, about 35-50%, about 35-45%, or about 35-40%), measured as mol %, of the total lipid content in the LNP, e.g., a lipid nanoparticle. [1002] In some embodiments, the LNPs of the present disclosure may include one or more cationic, or ionizable cationic, lipids that constitute about 35% to 55% or 40% to 50%, or about 35%, 36%, 37%, 38%, 39%, 40%, 41% 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, or about 55%. measured as mol %, of the total lipid content in the LNP, e.g., a lipid nanoparticle. Stealth lipid [1003] A stealth lipid provides control over particle size and stability of the lipid nanoparticle. The addition of such components may prevent complex aggregation and provide a means for increasing circulation lifetime and increasing the delivery of a lipid-nucleic acid pharmaceutical composition to target tissues. [1004] In some embodiments, the stealth lipid may be a polyethylene glycol-conjugated (PEGylated) lipid. These components may be selected to rapidly exchange out of the pharmaceutical composition in vivo (see, e.g., U.S. Pat.5,885,613). [1005] In some embodiments, the PEGylated lipid may be a polyethylene glycol (PEG) chain of up to 5 kDa in length covalently attached to a lipid with alkyl chain(s) of C₆-C₂₀. [1006] The use of polyethylene glycol (PEG)-modified phospholipids and derivatized lipids such as derivatized ceramides (PEG-CER), including N-Octanoyl-Sphingosine-1- [Succinyl(Methoxy Polyethylene Glycol)-2000] (C8 PEG-2000 ceramide) may be also contemplated by the present disclosure, either alone or in combination with other lipid pharmaceutical compositions together which comprise the transfer vehicle (e.g., a lipid nanoparticle). [1007] Contemplated PEGylated lipids may include, but are not limited to, a polyethylene glycol (PEG) chain of up to 5 kDa in length covalently attached to a lipid with alkyl chain(s) of C₆-C₂₀ (e.g., C₈, C₁₀, C₁₂, C₁₄, C₁₆, or C₁₈) length, such as a derivatized ceramide (e.g., N-octanoyl-sphingosine-1-[succinyl(methoxypolyethylene glycol)] (C8 PEG ceramide)). In some embodiments, the PEGylated lipid may be1,2-dimyristoyl-rac-glycero-3- methoxypolyethylene glycol (DMG-PEG); 1,2-distearoyl-sn-glycero-3-phosphoethanolamine- polyethylene glycol (DSPE- PEG); 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine- polyethylene glycol (DLPE-PEG); or 1,2-distearoyl-rac-glycero-polyethelene glycol (DSG- PEG). [1008] In some embodiments, the PEGylated lipid may be selected from the group consisting of: 1,2-dimyristoyl-rac-glycero-3-methoxypolyethylene glycol (DMG-PEG); 1,2- distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol (DSPE-PEG); 1,2- dilauroyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol (DLPE-PEG); or 1,2- distearoyl-rac-glycero-polyethelene glycol (DSG-PEG), PEG-DAG; PEG-PE; PEG-S-DAG; PEG-S-DMG; PEG-cer; a PEG-dialkyoxypropylcarbamate; 2-[(polyethylene glycol)-2000]- N,N-ditetradecylacetamide (ALC-0159); and combinations thereof. [1009] In some embodiments, the PEGylated lipid may comprise a PEG of a molecular weight in the range of about 2000 to about 2400 g/mol. [1010] In some embodiments, the PEGylated lipid may comprise a PEG being PEG2000 (or PEG-2K). [1011] In some embodiments, the PEG may have a high molecular weight, e.g., 2000- 2400 g/mol. In some embodiments, the PEG is PEG2000 (or PEG-2K). In some embodiments, the PEGylated lipid may be DMG-PEG2000, DSPE-PEG2000, DLPE-PEG2000, DSG- PEG2000, or C8 PEG2000. In some embodiments, the PEGylated lipid may be dimyristoyl- PEG2000 (DMG-PEG2000). [1012] In some embodiments, the stealth lipid may be a PEGylated lipid selected from the group consisting of: DMG-PEG2000, DSPE-PEG2000, DLPE-PEG2000, DSG-PEG2000, C8 PEG2000, ALC-0159 (2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide), and combinations thereof. [1013] In some embodiments, the stealth lipid may be DMG-PEG2000. [1014] In some embodiments, the stealth lipid may be ALC-0159. [1015] In some embodiments, the stealth lipid may be a polyoxazoline polymer- conjugated lipid. Polyoxazoline polymer-conjugated lipids suitable for the LNP compositions of the present disclosure are described, for example, in WO2022/173667 and WO2023/031394; incorporated herein by reference. [1016] In some embodiments, the stealth lipid may be a polysarcosine-conjugated (pSar) lipid. In some embodiments, the polysarcosine may comprise 25-45 sarcosine units. In some embodiments, the polysarcosine may comprise 25 sarcosine units. In some embodiments, the polysarcosine may comprise 35 sarcosine units. In some embodiments, the polysarcosine may comprise 45 sarcosine units. Nonlimiting examples of pSar lipids may include N-tetradecyl-pSar25, N-hexadecyl-pSar25, N-octadecyl-pSar25, N-dodecyl-pSar25, 1,2-dimyristoyl-sn-glycero-3-succinyl-N-polysarcosine-25 (DMG-pSar25), 1,2-dioleoyl-sn- glycero-3-phosphoethanolamine-N-polysarcosine-25 (18:1 PE (DOPE) pSar25), N,N- ditetradecylamine-N-succinyl[methyl(polysarcosine)45], N,N-ditetradecylamine-N- succinyl[methyl(polysarcosine)35], and N,N-ditetradecyl-polysarcosine-25. Further examples of pSar lipids suitable for the LNP compositions of the present disclosure are described in WO2020/070040, incorporated herein by reference. In some embodiments, the stealth lipid may be a polyoxazoline (POZ) or a poly(2- methyl-2-oxazoline) (PMOZ)-lipid conjugate. Exemplary polyoxazoline (POZ) or poly(2-methyl- 2-oxazoline) (PMOZ)-lipid conjugates are described in WO 2023/031394, incorporated herein by reference. [1017] In some embodiments, one or more PEG-modified lipids may constitute about 4% of the total lipids by molar ratio. In some embodiments, one or more PEG-modified lipids may constitute about 5% of the total lipids by molar ratio. In some embodiments, one or more PEG-modified lipids may constitute about 6% of the total lipids by molar ratio. For certain applications, such as pulmonary delivery, lipid nanoparticles in which the PEG-modified lipid component may constitutes about 5% of the total lipids by molar ratio have been found to be particularly suitable. [1018] In some embodiments, the LNPs of the present disclosure may include one or more stealth lipids at a molar ratio of from about 0.25% to about 6% or from about 1.00% to about 4.00% or at a molar ratio of about 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.50%, 1.75%, 2.00%, 2.25%, 2.50%, 2.75%, 3.00%, 3.50%, 4.00%, 4.50%, 5.00%, or about 5.50%, measured as mol %, of the total lipid content in the LNP, e.g., a lipid nanoparticle. [1019] In some embodiments, the LNPs of the present disclosure may include one or more stealth lipids at a molar ratio of about 0.25% to about 2.75% or about 1.00% to about 2.00% or at a molar ratio of about 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.50%, 1.75%, 2.00%, 2.25%, 2.50%, or about 2.75%, measured as mol %, of the total lipid content in the LNP, e.g., a lipid nanoparticle. Structural lipid [1020] A structural lipid component may provide stability to the lipid bilayer structure within the lipid nanoparticle. [1021] In some embodiments, the LNP may comprise one or more structural lipid. [1022] In some embodiments, the structural lipid may be a cholesterol-based lipid. [1023] Suitable cholesterol-based lipids may include, for example: DC-Choi (N,N- dimethyl-N-ethylcarboxamidocholesterol), 1,4-bis(3-N-oleylamino-propyl)piperazine (Gao et al., Biochem Biophys Res Comm. (1991) 179:280; Wolf et al., BioTechniques (1997) 23:139; U.S. Pat.5,744,335), imidazole cholesterol ester (“ICE”; WO2011/068810), sitosterol (22,23- dihydrostigmasterol), β-sitosterol, sitostanol, fucosterol, stigmasterol (stigmasta-5,22-dien-3- ol), ergosterol, desmosterol (3ß-hydroxy-5,24-cholestadiene), lanosterol (8,24-lanostadien-3b- ol), 7-dehydrocholesterol (Δ5,7-cholesterol), dihydrolanosterol (24,25-dihydrolanosterol), zymosterol (5α-cholesta-8,24-dien-3ß-ol), lathosterol (5α-cholest-7-en-3ß-ol), diosgenin ((3β,25R)-spirost-5-en-3-ol), campesterol (campest-5-en-3ß-ol), campestanol (5a-campestan- 3b-ol), 24-methylene cholesterol (5,24(28)-cholestadien-24-methylen-3ß-ol), cholesteryl margarate (cholest-5-en-3ß-yl heptadecanoate), cholesteryl oleate, cholesteryl stearate, and combinations thereof. [1024] In some embodiments, the cholesterol-based lipid may be cholesterol. [1025] In some embodiments, the structural lipid may be cholesterol. [1026] In some embodiments, the LNPs of the present disclosure may include one or more structural lipids at a molar ratio of from about 20% to about 50%, or from about 25% to about 45%, or from about 28.5% to about 43% or at a molar ratio of about 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41% 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or about 50%, measured as mol %, of the total lipid content in the LNP, e.g., a lipid nanoparticle. Helper lipid [1027] A helper lipid may enhance the structural stability of the LNP and may help the LNP in endosomal escape. A helper lipid may improve uptake and release of a nucleic acid, such as an mRNA, encapsulated in the LNP. [1028] In some embodiments, the helper lipid may be a zwitterionic lipid that is a neutral lipid. Without wishing to be bound by theory, the helper lipid can have fusogenic properties for enhancing uptake and release of the drug payload. [1029] Examples of helper lipids may be 1,2-dioleoyl-SN-glycero-3- phosphoethanolamine (DOPE); 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC); 1,2- dioleoyl-sn-glycero-3-phospho-L-serine (DOPS); 1,2-dielaidoyl-sn-glycero-3- phosphoethanolamine (DEPE); and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DPOC), dipalmitoylphosphatidylcholine (DPPC), 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC), 1,2-Distearoylphosphatidylethanolamine (DSPE), and 1,2-dilauroyl-sn-glycero-3- phosphoethanolamine (DLPE), or combinations thereof. [1030] Other exemplary helper lipids may be dioleoylphosphatidylcholine (DOPC), dioleoylphosphatidylglycerol (DOPG), dipalmitoylphosphatidylglycerol (DPPG), palmitoyloleoylphosphatidylcholine (POPC), palmitoyloleoyl-phosphatidylethanolamine (POPE), dioleoyl-phosphatidylethanolamine 4-(N-maleimidomethyl)-cyclohexane-l- carboxylate (DOPE-mal), dipalmitoyl phosphatidyl ethanolamine (DPPE), dimyristoylphosphoethanolamine (DMPE), phosphatidylserine, sphingolipids, cerebrosides, gangliosides, 16-O-monomethyl PE, 16-O-dimethyl PE, 18-1-trans PE, l-stearoyl-2-oleoyl- phosphatidyethanolamine (SOPE), or combinations thereof. [1031] In some embodiments, the helper lipid may be selected from the group consisting of: 1,2-dioleoyl-SN-glycero-3-phosphoethanolamine (DOPE); 1,2-distearoyl-sn- glycero-3-phosphocholine (DSPC); 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS); 1,2- dielaidoyl-sn-glycero-3-phosphoethanolamine (DEPE); and 1,2-dioleoyl-sn-glycero-3- phosphocholine (DPOC), dipalmitoylphosphatidylcholine (DPPC), DMPC, 1,2-dilauroyl-sn- glycero-3-phosphocholine (DLPC), 1,2-Distearoylphosphatidylethanolamine (DSPE), and 1,2- dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE), dioleoylphosphatidylcholine (DOPC), dioleoylphosphatidylglycerol (DOPG), dipalmitoylphosphatidylglycerol (DPPG), palmitoyloleoylphosphatidylcholine (POPC), palmitoyloleoyl-phosphatidylethanolamine (POPE), dioleoyl-phosphatidylethanolamine 4-(N-maleimidomethyl)-cyclohexane-l- carboxylate (DOPE-mal), dipalmitoyl phosphatidyl ethanolamine (DPPE), dimyristoylphosphoethanolamine (DMPE), phosphatidylserine, sphingolipids, sphingomyelins, ceramides, cerebrosides, gangliosides, 16-O-monomethyl PE, 16-O-dimethyl PE, 18-1-trans PE, l-stearoyl-2-oleoyl-phosphatidyethanolamine (SOPE), and combinations thereof. [1032] In some embodiments, the helper lipid may be DOPE. [1033] In some embodiments, the helper lipid may be DSPC. [1034] In some embodiments, the helper lipid may be DEPE. [1035] In some embodiments, the LNPs of the present disclosure may include one or more structural lipids at a molar ratio of from about 5% to about 35%, or from about 8% to about 30%, or from about 10% to about 30% or at a molar ratio of about 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, or about 35%, measured as mol %, of the total lipid content in the LNP, e.g., a lipid nanoparticle. LNPs formulations [1036] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising at least one cationic, or ionizable cationic, lipid, at least one stealth lipid, at least one structural lipid, and at least one helper lipid, wherein: [1037] - the cationic, or ionizable cationic, lipid may be selected from the group consisting of OF-02, cKK-E10, GL-HEPES-E3-E10-DS-3-E18-1, GL-HEPES-E3-E12-DS-4- E10, GL-HEPES-E3-E12-DS-3-E14, IM-001, IS-001, ALC-0315, SM-102, MC3, and combinations thereof; [1038] - the stealth lipid may be a PEGylated lipid, said PEGylated lipid comprising a PEG moiety being PEG2000 (or PEG-2K); [1039] - the structural lipid may be cholesterol; and [1040] - the helper lipid may be selected from the group consisting of 1,2-dioleoyl-SN- glycero-3-phosphoethanolamine (DOPE), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dielaidoyl-sn-glycero-3-phosphoethanolamine (DEPE), and combinations thereof. [1041] In some embodiments, the PEGylated lipid may be DMG-PEG2000 or ALC- 0159. [1042] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising at least one cationic, or ionizable cationic, lipid, at least one stealth lipid, at least one structural lipid, and at least one helper lipid, wherein (i) the cationic, or ionizable cationic, lipid may be selected from OF-02, cKK-E10, GL-HEPES-E3-E10-DS-3-E18-1, GL-HEPES-E3- E12-DS-4-E10, GL-HEPES-E3-E12-DS-3-E14, IM-001 or IS-001 ; (ii) the stealth lipid may be DMG-PEG2000; (iii) the structural lipid may be cholesterol; and (iv) the helper lipid may be DOPE. [1043] In some embodiments, the cationic, or ionizable cationic, lipid may be OF-02 or GL-HEPES-E3-E12-DS-4-E10. [1044] In some embodiments, the LNP may comprise (i) SM-102; (ii) DMG-PEG2000; (iii) cholesterol; and (iv) DSPC. [1045] In some embodiments, the LNP may comprise (i) ALC-0315; (ii) ALC-0159; (iii) cholesterol; and (iv) DSPC. [1046] In some embodiments, the LNP may comprise (i) MC3; (ii) DMG-PEG2000; (iii) cholesterol; and (iv) DSPC. [1047] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: [1048] a cationic, or ionizable cationic, lipid at a molar ratio of 35% to 55% or 40% to 50%, or at a molar ratio of 35%, 36%, 37%, 38%, 39%, 40%, 41% 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, or 55%; [1049] a stealth lipid at a molar ratio of 0.25% to 2.75% or 1.00% to 2.00% or at a molar ratio of 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.50%, 1.75%, 2.00%, 2.25%, 2.50%, or 2.75%; [1050] a structural lipid at a molar ratio of 20% to 50%, 25% to 45%, or 28.5% to 43% or at a molar ratio of 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41% 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%; and [1051] a helper lipid at a molar ratio of 5% to 35%, 8% to 30%, or 10% to 30% or at a molar ratio of 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, or 35%, [1052] wherein all of the molar ratios are relative to the total lipid content of the LNP. [1053] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: a cationic, or ionizable cationic, lipid at a molar ratio of 40%; a stealth lipid at a molar ratio of 1.5%; a structural lipid at a molar ratio of 28.5%; and a helper lipid at a molar ratio of 30%. [1054] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: a cationic, or ionizable cationic, lipid at a molar ratio of 45 to 50%; a stealth lipid at a molar ratio of 1.5 to 1.7%; a structural lipid at a molar ratio of 38 to 43%; and a helper lipid at a molar ratio of 9 to 10%. [1055] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: OF-02 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [1056] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: cKK-E10 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [1057] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: GL-HEPES-E3-E10-DS-3-E18-1 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [1058] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: GL-HEPES-E3-E12-DS-4-E10 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [1059] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: GL-HEPES-E3-E12-DS-3-E14 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [1060] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: IM-001 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [1061] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: IS-001 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DOPE at a molar ratio of 5% to 35%. [1062] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: SM-102 at a molar ratio of 35% to 55%; DMG-PEG2000 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DSPC at a molar ratio of 5% to 35%. [1063] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: ALC-0315 at a molar ratio of 35% to 55%; ALC-0159 at a molar ratio of 0.25% to 2.75%; cholesterol at a molar ratio of 20% to 50%; and DSPC at a molar ratio of 5% to 35%. [1064] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: OF-02 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [1065] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: cKK-E10 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [1066] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: GL-HEPES-E3-E10-DS-3-E18-1 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [1067] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: GL-HEPES-E3-E12-DS-4-E10 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [1068] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: GL-HEPES-E3-E12-DS-3-E14 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [1069] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: IM-001 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [1070] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: IS-001 at a molar ratio of 40%; DMG-PEG2000 at a molar ratio of 1.5%; cholesterol at a molar ratio of 28.5%; and DOPE at a molar ratio of 30%. [1071] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: 9-heptadecanyl 8-{(2-hydroxyethyl)[6-oxo-6-(undecyloxy)hexyl]amino}octanoate (SM-102) at a molar ratio of 50%; 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) at a molar ratio of 10%; cholesterol at a molar ratio of 38.5%; and 1,2-dimyristoyl-rac-glycero-3- methoxypolyethylene glycol-2000 (DMG-PEG2000) at a molar ratio of 1.5%. [1072] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: [(6Z,9Z,28Z,31Z)-heptatriaconta-6,9,28,31-tetraen-19-yl] 4- (dimethylamino)butanoate (MC3) at a molar ratio of 50%; 1,2-distearoyl-sn-glycero-3- phosphocholine (DSPC) at a molar ratio of 10%; cholesterol at a molar ratio of 38.5%; and 1,2- dimyristoyl-rac-glycero-3-methoxypolyethylene glycol-2000 (DMG-PEG2000) at a molar ratio of 1.5%. [1073] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: (4-hydroxybutyl)azanediyl]di(hexane-6,1-diyl) bis(2-hexyldecanoate) (ALC-0315) at a molar ratio of 46.3%; 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) at a molar ratio of 9.4%; cholesterol at a molar ratio of 42.7%; and 2-[(polyethylene glycol)-2000]-N,N- ditetradecylacetamide (ALC-0159) at a molar ratio of 1.6%. [1074] In some embodiments, the nucleic acid carrier may be an LNP, said LNP comprising: (4-hydroxybutyl)azanediyl]di(hexane-6,1-diyl) bis(2-hexyldecanoate) (ALC-0315) at a molar ratio of 47.4%; 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) at a molar ratio of 10%; cholesterol at a molar ratio of 40.9%; and 2-[(polyethylene glycol)-2000]-N,N- ditetradecylacetamide (ALC-0159) at a molar ratio of 1.7%. Manufacture of LNPs, size, distribution and rate of encapsulation Manufacture of LNPs [1075] Methods for manufacturing LNPs are known in the art. [1076] The present LNPs can be prepared by various techniques presently known in the art. For example, multilamellar vesicles (MLV) may be prepared according to conventional techniques, such as by depositing a selected lipid on the inside wall of a suitable container or vessel by dissolving the lipid in an appropriate solvent, and then evaporating the solvent to leave a thin film on the inside of the vessel or by spray drying. An aqueous phase may then be added to the vessel with a vortexing motion that results in the formation of MLVs. Unilamellar vesicles (ULV) can then be formed by homogenization, sonication or extrusion of the multilamellar vesicles. In addition, unilamellar vesicles can be formed by detergent removal techniques. [1077] Various methods are described in US 2011/0244026, US 2016/0038432, US 2018/0153822, US 2018/0125989, and PCT/US2020/043223 (filed July 23, 2020), which are incorporated by reference, and can be used to practice the present disclosure. One exemplary process entails encapsulating nucleic acid by mixing it with a mixture of lipids, without first pre- forming the lipids into lipid nanoparticles, as described in US 2016/0038432, which is incorporated by reference. Another exemplary process entails encapsulating nucleic acid by mixing pre-formed LNPs with nucleic acid, as described in US 2018/0153822. [1078] In some embodiments, the process of preparing nucleic acid-loaded LNPs may include a step of heating one or more of the solutions to a temperature greater than ambient temperature, the one or more solutions being the solution comprising the pre-formed lipid nanoparticles, the solution comprising the nucleic acid and the mixed solution comprising the LNP-encapsulated nucleic acid. In some embodiments, the process may include the step of heating one or both of the nucleic acid solution and the pre-formed LNP solution, prior to the mixing step. In some embodiments, the process may include heating one or more of the solutions comprising the pre-formed LNPs, the solution comprising the nucleic acid and the solution comprising the LNP-encapsulated nucleic acid, during the mixing step. In some embodiments, the process may include the step of heating the LNP- encapsulated nucleic acid, after the mixing step. In some embodiments, the temperature to which one or more of the solutions may be heated may be, or may be greater than, about 30°C, 37°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, or 70°C. In some embodiments, the temperature to which one or more of the solutions may be heated may range from about 25-70°C, about 30-70°C, about 35-70°C, about 40-70°C, about 45-70°C, about 50-70°C, or about 60-70°C. In some embodiments, the temperature may be about 65°C. [1079] Various methods may be used to prepare a nucleic acid solution suitable for the present disclosure. [1080] In some embodiments, the nucleic acid may be prepared in an aqueous buffer and mixed with an amphiphilic solution containing the lipid components of the LNPs. An amphiphilic solution for dissolving the four lipid components of the LNPs may be an alcohol solution. In some embodiments, the alcohol may be ethanol. The aqueous buffer may be, for example, a citrate, phosphate, acetate, or succinate buffer and may have a pH of about 3.0- 7.0, e.g., about 3.5, about 4.0, about 4.5, about 5.0, about 5.5, about 6.0, or about 6.5. The buffer may contain other components such as a salt (e.g., sodium, potassium, and/or calcium salts). In particular embodiments, the aqueous buffer may have 1 mM citrate, 150 mM NaCl, pH 4.5. [1081] The process for making a composition comprising LNPs and nucleic acid(s) may involve mixing of a buffered nucleic acid solution with a solution of lipids in ethanol in a controlled homogeneous manner, where the ratio of lipids:nucleic acid may be maintained throughout the mixing process. In this illustrative example, the nucleic acid may be presented in an aqueous buffer containing citric acid monohydrate, tri-sodium citrate dihydrate, and sodium chloride. The nucleic acid solution may be added to the solution (1 mM citrate buffer, 150 mM NaCl, pH 4.5). The lipid mixture of four lipids (e.g., a cationic lipid, a PEGylated lipid, a cholesterol-based lipid, and a helper lipid) may be dissolved in ethanol. The aqueous nucleic acid solution and the ethanol lipid solution may be mixed at a volume ratio of 4:1 in a “T” mixer with a near “pulseless” pump system. The resultant mixture may be then subjected for downstream purification and buffer exchange. The buffer exchange may be achieved using dialysis cassettes or a TFF system. TFF may be used to concentrate and buffer-exchange the resulting nascent LNP immediately after formation via the T-mix process. The diafiltration process is a continuous operation, keeping the volume constant by adding appropriate buffer at the same rate as the permeate flow. [1082] In some embodiments, nucleic acid may be directly dissolved in a buffer solution described herein. In some embodiments, a nucleic acid solution may be generated by mixing a nucleic acid stock solution with a buffer solution prior to mixing with a lipid solution for encapsulation. In some embodiments, a nucleic acid solution may be generated by mixing a nucleic acid stock solution with a buffer solution immediately before mixing with a lipid solution for encapsulation. In some embodiments, a suitable nucleic acid stock solution may contain nucleic acid in water or a buffer at a concentration at or greater than about 0.2 mg/ml, 0.4 mg/ml, 0.5 mg/ml, 0.6 mg/ml, 0.8 mg/ml, 1.0 mg/ml, 1.2 mg/ml, 1.4 mg/ml, 1.5 mg/ml, or 1.6 mg/ml, 2.0 mg/ml, 2.5 mg/ml, 3.0 mg/ml, 3.5 mg/ml, 4.0 mg/ml, 4.5 mg/ml, or 5.0 mg/ml. [1083] In some embodiments, a nucleic acid stock solution may be mixed with a buffer solution using a pump. Exemplary pumps may include but are not limited to gear pumps, peristaltic pumps and centrifugal pumps. Typically, the buffer solution may be mixed at a rate greater than that of the nucleic acid stock solution. For example, the buffer solution may be mixed at a rate at least 1x, 2x, 3x, 4x, 5x, 6x, 7x, 8x, 9x, 10x, 15x, or 20x greater than the rate of the nucleic acid stock solution. In some embodiments, a buffer solution may be mixed at a flow rate ranging between about 100-6000 ml/minute (e.g., about 100-300 ml/minute, 300-600 ml/minute, 600-1200 ml/minute, 1200-2400 ml/minute, 2400-3600 ml/minute, 3600-4800 ml/minute, 4800-6000 ml/minute, or 60-420 ml/minute). In some embodiments, a buffer solution may be mixed at a flow rate of, or greater than, about 60 ml/minute, 100 ml/minute, 140 ml/minute, 180 ml/minute, 220 ml/minute, 260 ml/minute, 300 ml/minute, 340 ml/minute, 380 ml/minute, 420 ml/minute, 480 ml/minute, 540 ml/minute, 600 ml/minute, 1200 ml/minute, 2400 ml/minute, 3600 ml/minute, 4800 ml/minute, or 6000 ml/minute. [1084] In some embodiments, a nucleic acid stock solution may be mixed at a flow rate ranging between about 10-600 ml/minute (e.g., about 5-50 ml/minute, about 10-30 ml/minute, about 30-60 ml/minute, about 60-120 ml/minute, about 120-240 ml/minute, about 240-360 ml/minute, about 360-480 ml/minute, or about 480-600 ml/minute). In some embodiments, a nucleic acid stock solution is mixed at a flow rate of or greater than about 5 ml/minute, 10 ml/minute, 15 ml/minute, may be ml/minute, 25 ml/minute, 30 ml/minute, 35 ml/minute, 40 ml/minute, 45 ml/minute, 50 ml/minute, 60 ml/minute, 80 ml/minute, 100 ml/minute, 200 ml/minute, 300 ml/minute, 400 ml/minute, 500 ml/minute, or 600 ml/minute. [1085] The process of incorporation of a desired nucleic acid into a lipid nanoparticle is referred to as “loading.” Exemplary methods are described in Lasic et al., FEBS Lett. (1992) 312:255-8, which is incorporated by reference. The LNP-incorporated nucleic acids may be completely or partially located in the interior space of the lipid nanoparticle, within the bilayer membrane of the lipid nanoparticle, or associated with the exterior surface of the lipid nanoparticle membrane. The incorporation of a nucleic acid into lipid nanoparticles is also referred to herein as “encapsulation” wherein the nucleic acid is entirely or substantially contained within the interior space of the lipid nanoparticle. In some embodiments, the nucleic acid may be complexed with the cationic, or ionizable cationic, lipid of the LNPs. Size, distribution, and rate of encapsulation [1086] Suitable LNPs may be made in various sizes. In some embodiments, decreased size of lipid nanoparticles may be associated with more efficient delivery of a nucleic acid. Selection of an appropriate LNP size may take into consideration the site of the target cell or tissue and to some extent the application for which the lipid nanoparticle is being made. [1087] The lipid nanoparticles (LNPs) may be characterized by several parameters well-known in the art, such as the mean diameter size, the mode diameter size, the polydispersity index (PI) which reflects the homogeneity of the size distribution of the LNPs, the pKa, and/or the zeta potential which reflects the global surface charge of the LNPs. [1088] A variety of methods known in the art are available for sizing of a population of lipid nanoparticles. Preferred methods herein utilize ZETASIZER NANO ZS (Malvern Panalytical) to measure LNP particle size. In one protocol, 10 μL of an LNP sample are mixed with 990 μL of 10% trehalose. This solution may be loaded into a cuvette and then put into the Zetasizer machine. The z-average diameter (nm), or cumulants mean, is regarded as the average size for the LNPs in the sample. The ZETASIZER machine can also be used to measure the polydispersity index (PDI) by using dynamic light scattering (DLS) and cumulant analysis of the autocorrelation function. Average LNP diameter may be reduced by sonication of formed LNP. Intermittent sonication cycles may be alternated with quasi-elastic light scattering (QELS) assessment to guide efficient lipid nanoparticle synthesis. [1089] In some embodiments, the LNPs may have a mean diameter size of less than 150 nm, or less than 120 nm, or less than 100 nm, or less than 90 nm. [1090] In some embodiments, the majority of purified LNPs, i.e., greater than about 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% of the LNPs, may have a mean diameter size of about 70-150 nm (e.g., about 145 nm, about 140 nm, about 135 nm, about 130 nm, about 125 nm, about 120 nm, about 115 nm, about 110 nm, about 105 nm, about 100 nm, about 95 nm, about 90 nm, about 85 nm, or about 80 nm). In some embodiments, substantially all (e.g., greater than 80 or 90%) of the purified lipid nanoparticles may have a mean diameter size of about 70-150 nm (e.g., about 145 nm, about 140 nm, about 135 nm, about 130 nm, about 125 nm, about 120 nm, about 115 nm, about 110 nm, about 105 nm, about 100 nm, about 95 nm, about 90 nm, about 85 nm, or about 80 nm). [1091] In some embodiments, the LNPs in the present composition may have an mean diameter size of less than 150 nm, less than 120 nm, less than 100 nm, less than 90 nm, less than 80 nm, less than 70 nm, less than 60 nm, less than 50 nm, less than 30 nm, or less than 20 nm. [1092] In some embodiments, greater than about 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% of the LNPs in the present composition may have a mean diameter size ranging from about 40-90 nm (e.g., about 45-85 nm, about 50-80 nm, about 55-75 nm, about 60-70 nm) or about 50-70 nm (e.g., 55-65 nm). In some embodiments, the LNPs may have a mean diameter size ranging from about 40-90 nm (e.g., about 45-85 nm, about 50-80 nm, about 55-75 nm, about 60-70 nm). [1093] In some embodiments, the dispersity, or measure of heterogeneity in size of molecules (PDI), of LNPs may be less than about 0.5. [1094] The “polydispersity index” (PDI or PI) is a measurement of the homogeneous or heterogeneous size distribution of the individual lipid nanoparticles in a lipid nanoparticles mixture and indicates the breadth of the particle distribution in a mixture. The PI can be determined, for example, as described herein. [1095] In one embodiment, the polydispersity index of the nanoparticles described herein may be measured by dynamic light scattering. [1096] In some embodiments, the PDI may be measured by a ZETASIZER machine as described above. [1097] In some embodiments, the dispersity, or measure of heterogeneity in size of molecules (PDI), of LNPs may be less than about 0.5. In some embodiments, an LNP may have a PDI of less than about 0.5, less than about 0.4, less than about 0.3, less than about 0.28, less than about 0.25, less than about 0.23, less than about 0.20, less than about 0.18, less than about 0.16, less than about 0.14, less than about 0.12, less than about 0.10, or less than about 0.08. [1098] The LNPs may contain or encapsulate at least one nucleic acid. [1099] In such case, the LNPs may have a global surface charge which is the sum of the negative and positive electric charges at the surface of the particles, and which is represented by the zeta potential. The zeta potential is the potential difference between the dispersion medium and the stationary layer of fluid attached to the dispersed particle. Zeta potential is widely used for quantification of the magnitude of the electrical charge at the double layer. [1100] Zeta potential can be calculated using theoretical models and experimentally determined using electrophoretic mobility or dynamic electrophoretic mobility measurements. Electrophoresis may be used for estimating zeta potential of particulates. In practice, the zeta potential of a dispersion can be measured by applying an electric field across the dispersion. Particles within the dispersion with a zeta potential will migrate toward the electrode of opposite charge with a velocity proportional to the magnitude of the zeta potential. This velocity may be measured using the technique of the Laser Doppler Anemometer. The frequency shift or phase shift of an incident laser beam caused by these moving particles may be measured as the particle mobility, and this mobility may be converted to the zeta potential by inputting the dispersant viscosity and dielectric permittivity, and the application of the Smoluchowski theories. Electrophoretic velocity is proportional to electrophoretic mobility, which is the measurable parameter. There are several theories that link electrophoretic mobility with zeta potential. [1101] Suitable systems such as the NICOMP 380 ZLS system or the MALVERN NANOZS can be used for determining the zeta potential. Such systems usually measure the electrophoretic mobility and stability of charged particles in liquid suspension. These values are a predictor of the repulsive forces being exerted by the particles in suspension and are directly related to the stability of the colloidal system. [1102] At pH neutral, the zeta potential of the lipid nanoparticles as disclosed herein may be close to neutral. [1103] In one advantage, to have a zeta potential close to zero facilitates particle mobility in the body, reduces opsonization and augment access to target tissues. [1104] In one embodiment, at pH from 6.0 to 7.5, the zeta potential of the lipid nanoparticles may be from about -3 mV to about +3 mV, for example from about -1 mV to about +1 mV, and for example from about -0.5 mV to about +0.5 mV. [1105] The lipid nanoparticles described herein can be formed by adjusting, at the time of the preparation, a positive to negative charge, depending on the charge ratio of the ionizable lipidic compound as disclosed herein (cationic charges from the quaternary ammonium: N of the terminal radical of formula (I)) to the nucleic acid (anionic charges from the phosphate: P) and mixing the nucleic acid and the lipidic compound. The charges of the ionizable lipidic compound and of the nucleic acid are charges at a selected pH, such as a pH of the formulating process, which may be from about 3.0 to about 4.5. [1106] The +/- (N/P) charge ratio of the lipidic compound as disclosed herein to the nucleic acids can be calculated by the following equation. (+/- charge ratio) = [(cationic lipid amount (mol)) * (the total number of positive charges in the cationic lipid)]:[(nucleic acid amount (mol)) * (the total number of negative charges in nucleic acid)]. [1107] The nucleic acid amount and the lipidic compound amount can be easily determined by one skilled in the art in view of a loading amount upon preparation of the nanoparticles. [1108] In one embodiment, the calculated charge ratio of positive charges to negative charges may range from about 1:1 to about 14:1, for example from about 2:1 to about 12:1, for example from about 4:1 to about 10:1, and for example from about 6:1 to about 8:1, and for example may be about 6:1. [1109] In some embodiments, an LNP may have a N/P ratio of between 1 and 10. In some embodiments, a lipid nanoparticle may have a N/P ratio above 1, about 1, about 2, about 3, about 4, about 5, about 6, about 7, or about 8. In further embodiments, a typical LNP herein may have an N/P ratio of 4. [1110] Encapsulation efficiency is a parameter in evaluating the efficacy of Lipid Nanoparticles (LNPs) for delivery of nucleic acids (e.g., mRNA, siRNA) in therapeutic applications. It quantifies the percentage of the total input nucleic acid that is successfully encapsulated within the LNP carrier system. A high encapsulation efficiency may be desirable as it minimizes wasted nucleic acid and ensures efficient delivery to target cells. [1111] Several methods can be employed to measure the unencapsulated (free) and encapsulated nucleic acid fractions within LNP formulations. As examples of suitable methods, one may mention: [1112] Gel electrophoresis in which free nucleic acid migrates faster through a gel matrix compared to LNP-encapsulated nucleic acid. By quantifying the nucleic acid bands using appropriate staining techniques, the percentage of encapsulated and unencapsulated fractions can be calculated. [1113] Size-Exclusion Chromatography (SEC) in which molecules are separated based on their size. LNPs, being larger than free nucleic acid, elute from the column earlier. By measuring the nucleic acid content in different fractions, the encapsulated and unencapsulated fractions can be quantified. [1114] Fluorescence Assays relying upon the properties of certain nucleic acid fluorescent probes to exhibit enhanced fluorescence when bound to nucleic acids. By measuring the fluorescence intensity of the LNP sample before and after treatment with a lysis agent that disrupts the LNP structure and releases the encapsulated nucleic acid, the amount of unencapsulated and encapsulated nucleic acid can be determined. [1115] Following quantification of both fractions, the encapsulation efficiency (EE) is typically calculated as: [1116] EE (%) = (Encapsulated nucleic acid / Total input nucleic acid) x 100%. [1117] In some embodiments, greater than about 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% of the purified LNPs encapsulate a nucleic acid within each individual particle. In some embodiments, substantially all (e.g., greater than 80% or 90%) of the purified lipid nanoparticles encapsulate a nucleic acid within each individual particle. In some embodiments, a lipid nanoparticle may have an encapsulation efficiency of between 50% and 99%; or greater than about 60, 65, 70, 75, 80, 85, 90, 92, 95, 98, or 99%. Typically, lipid nanoparticles for use herein have an encapsulation efficiency of at least 90% (e.g., at least 91, 92, 93, 94, or 95%). [1118] In some embodiments, an LNP may have an encapsulation efficiency of greater than about 80%. In some embodiments, an LNP may have an encapsulation efficiency of greater than about 85%. In some embodiments, an LNP may have an encapsulation efficiency of greater than about 90%. In some embodiments, an LNP may have an encapsulation efficiency of greater than about 92%. In some embodiments, an LNP may have an encapsulation efficiency of greater than about 95%. In some embodiments, an LNP may have an encapsulation efficiency of greater than about 98%. In some embodiments, an LNP may have an encapsulation efficiency of greater than about 99%. Typically, LNPs for use with compositions of the disclosure have an encapsulation efficiency of at least 90%-95%. [1119] The Encapsulation Efficiency may be determined by a RIBOGREEN assay. [1120] In some embodiments, a composition according to the present disclosure comprising LNPs may contain at least about 0.5 μg, 1 μg, 5 μg, 10 μg, 100 μg, 500 μg, or 1000 μg of encapsulated nucleic acid. In some embodiments, a composition contains from about 0.1 μg to about 1000 μg, at least about 0.5 μg, at least about 0.8 μg, at least about 1 μg, at least about 5 μg, at least about 8 μg, at least about 10 μg, at least about 50 μg, at least about 100 μg, at least about 500 μg, or at least about 1000 μg of encapsulated nucleic acid. [1121] In some embodiments, a composition of the disclosure may contain from about 0.1 μg to about 1000 μg,or from about 0.5 µg to about 500 µg, or from about 0.8 µg to about 100 µg, or from about 1 µg to about 50 µg, or from about 5 µg to about 10 µg of encapsulated nucleic acid. Nucleic acid [1122] A nucleic acid suitable for the present disclosure may be a deoxyribonucleic acid (DNA) or a ribonucleic acid (RNA). Nucleic acid includes genomic DNA, cDNA, mRNA, recombinantly produced and chemically synthesized molecules. [1123] A nucleic acid may be a single-stranded or a double-stranded molecule, linear or closed covalently to form a circle. A nucleic acid may be a double stranded RNA (dsRNA); a single stranded RNA (ssRNA); a double stranded DNA (dsDNA); a single stranded DNA (ssDNA); and combinations thereof. [1124] A nucleic acid may be of eukaryotic or prokaryotic origin, and for example of human, animal, plant, parasitic, bacterial, yeast or viral origin and the like. It may be obtained by any technique known to persons skilled in the art and for example by screening libraries, by chemical synthesis or alternatively by mixed methods including chemical or enzymatic modification of sequences obtained by screening libraries. It may be chemically modified. [1125] In some embodiments, the nucleic acid may be an RNA or a DNA. [1126] In some embodiments, the nucleic acid may be selected from the group consisting of: double stranded RNA (dsRNA); single stranded RNA (ssRNA); double stranded DNA (dsDNA); single stranded DNA (ssDNA); and combinations thereof. [1127] A nucleic acid may be selected from the group consisting of: messenger RNA (mRNA); short interference RNA (siRNA): self-amplifying RNA (saRNA); micro RNA (miRNA); small nuclear RNA (snRNA); small nucleolar RNA (snoRNA); transfer RNA (tRNA): ribosomal RNA (rRNA): mitochondrial RNA (mtRNA): short hairpin RNA (shRNA): transfer-messenger RNA (tmRNA): viral RNA (vRNA): RNA (bpRNA): blunt-ended RNA; antisense oligonucleotide (ASO); plasmid DNA (pDNA); closed-ended DNA (ceDNA); and combinations thereof. [1128] In some embodiments, a nucleic acid may be an RNA. [1129] In some embodiments, a nucleic acid may be a messenger RNA (mRNA); a microRNA (miRNA); a short (or small) interference RNA (siRNA); small hairpin RNA (shRNA); a long non-coding RNA (lncRNA); an asymmetrical interfering RNA (aiRNA); a self-amplifying RNA (saRNA); a guide RNA (gRNA); and combinations thereof. [1130] In some embodiments, LNPs may contain as nucleic acids a mRNA encoding for a CRISPR protein, such as CRISPR/Cas9, and a guide RNA (gRNA). A gRNA may be provided as rRNA:tracrRNA duplex or as a single guide RNA (sgRNA). In some embodiments, a CRISPR protein may be provided directly as a polypeptide and not as an mRNA encoding for a CRISPR protein. [1131] In some embodiments, an RNA may be a messenger RNA (mRNA). [1132] In some embodiments, nucleic acid can be made by chemical synthesis or by in vitro transcription (IVT) of a DNA template. In this process, in an IVT process, a cDNA template is used to produce a nucleic acid transcript and the DNA template is degraded by a DNase. The transcript is purified by depth filtration and tangential flow filtration (TFF). The purified transcript is further modified by adding a cap and a tail, and the modified RNA is purified again by depth filtration and TFF. mRNA [1133] In some embodiments, the RNA may be a self-replicating mRNA. [1134] In some embodiments, the RNA may be a non self-replicating mRNA. [1135] In some embodiments, the RNA may be modified or unmodified. [1136] In some embodiments, the nucleic acids of the present disclosure may be messenger RNAs (mRNAs). mRNAs can be modified or unmodified. mRNAs may contain one or more coding and non-coding regions. A coding region may be alternatively referred to as an open reading frame (ORF). Non-coding regions in an mRNA include the 5’ cap, 5’ untranslated region (UTR), 3’ UTR, and a polyA tail. An mRNA can be purified from natural sources, produced using recombinant expression systems (e.g., in vitro transcription) and optionally purified, or chemically synthesized. [1137] In some embodiments, the RNA may comprise at least one of a 5’ cap, a 5’ untranslated region (UTR), a 3’ UTR, a polyA tail. [1138] In some embodiments, the RNA may comprise a 5’ cap, a 5’ untranslated region (UTR), a 3’ UTR and a polyA tail. [1139] In some embodiments, the RNA may be an mRNA comprising an open reading frame (ORF) encoding an antigen. [1140] In some embodiments, the mRNA may comprise an ORF encoding an antigen of interest. In some embodiments, the RNA (e.g., mRNA) may further comprise at least one 5’ UTR, 3’ UTR, a poly(A) tail, and/or a 5’ cap. In some embodiments, the mRNA may comprise (i) a 5’ cap as defined herein; (ii) a 5’ untranslated region (UTR) as defined herein; (iii) a protein coding region; (iv) a 3’ UTR as defined herein; and (v) a polyA tail. Typically, the 3’ end of (i) bonds directly to the 5’ end of (ii) via a 3’ to 5’ phosphodiester linkage; the 3’ end of (ii) bonds directly to the 5’ end of (iii) via a 3’ to 5’ phosphodiester linkage; the 3’ end of (iii) bonds directly to the 5’ end of (iv) via a 3’ to 5’ phosphodiester linkage; and the 3’ end of (iv) bonds directly to the 5’ end of (v) via a 3’ to 5’ phosphodiester linkage. [1141] In some embodiments, the mRNA may comprise (i) a 5’ cap; (ii) a 5’ untranslated region (UTR); (iii) an ORF encoding an antigen; (iv) a 3’ UTR; and (v) a polyA tail. [1142] In some embodiments, the mRNA may comprise at least one, at least two, at least three or more stop codon(s). [1143] In some embodiments, the mRNA may comprise at least one, at least two, at least three or more stop codon(s), wherein the stop codon(s) can be selected from UAA, UGA and UAG, and wherein the at least two, at least three or more stop codon(s) can be identical or different. Typically, the at least one stop codon comprises UAA or UGA (e.g. UAA). Typically, the at least two stop codons comprise at least two identical stop codons, such as UAA or UGA (e.g. UAAUAA or UGAUGA) or at least two different stop codons, which may in particular be selected from UAA and UGA (e.g. UGAUAA). Typically, the at least three stop codons comprise UAA, UGA and UAG (e.g. UGAUAAUAG). [1144] An mRNA sequence is presented in the 5’ to 3’ direction unless otherwise indicated. 5’ Cap [1145] An mRNA 5’ cap can provide resistance to nucleases found in most eukaryotic cells and promote translation efficiency. Several types of 5’ caps are known. A 7- methylguanosine cap (also referred to as “m7G” or “Cap-0”), comprises a guanosine that is linked through a 5’ – 5’ - triphosphate bond to the first transcribed nucleotide. [1146] A 5' cap is typically added as follows: first, an RNA terminal phosphatase removes one of the terminal phosphate groups from the 5’ nucleotide, leaving two terminal phosphates; guanosine triphosphate (GTP) is then added to the terminal phosphates via a guanylyl transferase, producing a 5 ‘5 ‘5 triphosphate linkage; and the 7-nitrogen of guanine is then methylated by a methyltransferase. Examples of cap structures include, but are not limited to, m7G(5’)ppp, (5’(A,G(5’)ppp(5’)A, and G(5’)ppp(5’)G. Additional cap structures are described in U.S. Publication No. US 2016/0032356 and U.S. Publication No. US 2018/0125989, which are incorporated herein by reference. [1147] 5’-capping of polynucleotides may be completed concomitantly during the in vitro-transcription reaction using the following chemical RNA cap analogs to generate the 5’- guanosine cap structure according to manufacturer protocols: 3’-O-Me-m7G(5’)ppp(5’)G (the ARCA cap); G(5’)ppp(5’)A; G(5’)ppp(5’)G; m7G(5’)ppp(5’)A; m7G(5’)ppp(5’)G; m7G(5')ppp(5')(2'oMeA)pG; m7G(5')ppp(5')(2'oMeA)pU; m7G(5')ppp(5')(2'oMeG)pG (New England BioLabs, Ipswich, MA; TriLink Biotechnologies).5’-capping of modified RNA may be completed post-transcriptionally using a vaccinia virus capping enzyme to generate the Cap 0 structure: m7G(5’)ppp(5’)G. Cap 1 structure may be generated using both vaccinia virus capping enzyme and a 2’-O methyl-transferase to generate: m7G(5’)ppp(5’)G-2’-O-methyl. Cap 2 structure may be generated from the Cap 1 structure followed by the 2’-O-methylation of the 5’-antepenultimate nucleotide using a 2’-O methyl-transferase. Cap 3 structure may be generated from the Cap 2 structure followed by the 2’-O-methylation of the 5’- preantepenultimate nucleotide using a 2’-O methyl-transferase. [1148] In some embodiments, the mRNA of the disclosure comprises a 5’ cap selected from the group consisting of 3’-O-Me-m7G(5’)ppp(5’)G (the ARCA cap), G(5’)ppp(5’)A, G(5’)ppp(5’)G, m7G(5’)ppp(5’)A, m7G(5’)ppp(5’)G, m7G(5')ppp(5')(2'OMeA)pG, m7G(5')ppp(5')(2'OMeA)pU, and m7G(5')ppp(5')(2'OMeG)pG. [1149] In some embodiments, the mRNA of the disclosure comprises a 5’ cap of: Untranslated Region (UTR) [1151] In some embodiments, the mRNA of the disclosure may include a 5’ and/or 3’ untranslated region (UTR). In mRNA, the 5’ UTR starts at the transcription start site and continues to the start codon but does not include the start codon. The 3’ UTR starts immediately following the stop codon and continues until the transcriptional termination signal. [1152] In some embodiments, the mRNA disclosed herein may comprise a 5’ UTR that includes one or more elements that affect an mRNA’s stability or translation. [1153] In some embodiments, a 5’ UTR may be about 10 to 5,000 nucleotides in length. [1154] In some embodiments, a 5’ UTR may be about 50 to 500 nucleotides in length. In some embodiments, the 5’ UTR may be at least about 10 nucleotides in length, about 20 nucleotides in length, about 30 nucleotides in length, about 40 nucleotides in length, about 50 nucleotides in length, about 100 nucleotides in length, about 150 nucleotides in length, about 200 nucleotides in length, about 250 nucleotides in length, about 300 nucleotides in length, about 350 nucleotides in length, about 400 nucleotides in length, about 450 nucleotides in length, about 500 nucleotides in length, about 550 nucleotides in length, about 600 nucleotides in length, about 650 nucleotides in length, about 700 nucleotides in length, about 750 nucleotides in length, about 800 nucleotides in length, about 850 nucleotides in length, about 900 nucleotides in length, about 950 nucleotides in length, about 1,000 nucleotides in length, about 1,500 nucleotides in length, about 2,000 nucleotides in length, about 2,500 nucleotides in length, about 3,000 nucleotides in length, about 3,500 nucleotides in length, about 4,000 nucleotides in length, about 4,500 nucleotides in length or about 5,000 nucleotides in length. [1155] In some embodiments, the mRNA disclosed herein may comprise a 3’ UTR comprising one or more of a polyadenylation signal, a binding site for proteins that affect an mRNA’s stability of location in a cell, or one or more binding sites for miRNAs. [1156] In some embodiments, a 3’ UTR may be 50 to 5,000 nucleotides in length or longer. [1157] In some embodiments, a 3’ UTR may be 50 to 1,000 nucleotides in length or longer. In some embodiments, the 3’ UTR may be at least about 50 nucleotides in length, about 100 nucleotides in length, about 150 nucleotides in length, about 200 nucleotides in length, about 250 nucleotides in length, about 300 nucleotides in length, about 350 nucleotides in length, about 400 nucleotides in length, about 450 nucleotides in length, about 500 nucleotides in length, about 550 nucleotides in length, about 600 nucleotides in length, about 650 nucleotides in length, about 700 nucleotides in length, about 750 nucleotides in length, about 800 nucleotides in length, about 850 nucleotides in length, about 900 nucleotides in length, about 950 nucleotides in length, about 1,000 nucleotides in length, about 1,500 nucleotides in length, about 2,000 nucleotides in length, about 2,500 nucleotides in length, about 3,000 nucleotides in length, about 3,500 nucleotides in length, about 4,000 nucleotides in length, about 4,500 nucleotides in length, or about 5,000 nucleotides in length. [1158] In some embodiments, the mRNA disclosed herein may comprise a 5’ or 3’ UTR that may be derived from a gene distinct from the one encoded by the mRNA transcript (i.e., the UTR may be a heterologous UTR). [1159] In some embodiments, the 5’ and/or 3’ UTR sequences can be derived from mRNA which are stable (e.g., globin, actin, GAPDH, tubulin, histone, or citric acid cycle enzymes) to increase the stability of the mRNA. For example, a 5’ UTR sequence may include a partial sequence of a CMV immediate-early 1 (IE1) gene, or a fragment thereof, to improve the nuclease resistance and/or improve the half-life of the mRNA. Also contemplated is the inclusion of a sequence encoding human growth hormone (hGH), or a fragment thereof, to the 3’ end or untranslated region of the mRNA. Generally, these modifications improve the stability and/or pharmacokinetic properties (e.g., half-life) of the mRNA relative to their unmodified counterparts, and include, for example, modifications made to improve such mRNA resistance to in vivo nuclease digestion. [1160] Exemplary 5’ UTRs include a sequence derived from a CMV immediate-early 1 (IE1) gene (U.S. Publication Nos. 2014/0206753 and 2015/0157565, each of which is incorporated herein by reference), or the sequence GGGAUCCUACC (SEQ ID NO: 6) (U.S. Publication No.2016/0151409, incorporated herein by reference). [1161] In various embodiments, the 5’ UTR may be derived from the 5’ UTR of a TOP gene. TOP genes are typically characterized by the presence of a 5’-terminal oligopyrimidine (TOP) tract. Furthermore, most TOP genes are characterized by growth-associated translational regulation. However, TOP genes with a tissue specific translational regulation are also known. In some embodiments, the 5’ UTR derived from the 5’ UTR of a TOP gene lacks the 5’ TOP motif (the oligopyrimidine tract) (e.g., U.S. Publication Nos. 2017/0029847, 2016/0304883, 2016/0235864, and 2016/0166710, each of which is incorporated herein by reference). [1162] In some embodiments, the 5’ UTR may be derived from a ribosomal protein Large 32 (L32) gene (U.S. Publication No.2017/0029847, supra). [1163] In some embodiments, the 5’ UTR may be derived from the 5’ UTR of an hydroxysteroid (17-b) dehydrogenase 4 gene (HSD17B4) (U.S. Publication No. 2016/0166710, supra). [1164] In some embodiments, the 5’ UTR may be derived from the 5’ UTR of an ATP5A1 gene (U.S. Publication No.2016/0166710, supra). [1165] In some embodiments, the 5’UTR may be derived from the 5’ UTR of cytomegalovirus (CMV) and may have a nucleic acid sequence set forth in SEQ ID NO: 1 reproduced below: [1166] GGACAGAUCGCCUGGAGACGCCAUCCACGCUGUUUUGACCUCCAUAGA AGACACCGGGACCGAUCCAGCCUCCGCGGCCGGGAACGGUGCAUUGGAACGCGGAU UCCCCGUGCCAAGAGUGACUCACCGUCCUUGACACG (SEQ ID NO: 1). [1167] In some embodiments, an internal ribosome entry site (IRES) may be used instead of a 5’ UTR. [1168] In some embodiments, the 3’UTR may be derived from the 3’ UTR of hGH and may have a nucleic acid sequence set forth in SEQ ID NO: 2 reproduced below: [1169] CGGGUGGCAUCCCUGUGACCCCUCCCCAGUGCCUCUCCUGGCCCUGG AAGUUGCCACUCCAGUGCCCACCAGCCUUGUCCUAAUAAAAUUAAGUUGCAUC (SEQ ID NO: 2). [1170] The 5’ UTR and 3’UTR are described in further detail in WO2012/075040, incorporated herein by reference. Polyadenylated Tail [1171] As used herein, the terms “poly(A) sequence,” “poly(A) tail,” and “poly(A) region” refer to a sequence of adenosine nucleotides at the 3’ end of the mRNA molecule. The poly(A) tail may confer stability to the mRNA and protect it from exonuclease degradation. The poly(A) tail may enhance translation. In some embodiments, the poly(A) tail may be essentially homopolymeric. For example, a poly(A) tail of 100 adenosine nucleotides may have essentially a length of 100 nucleotides. In some embodiments, the poly(A) tail may be interrupted by at least one nucleotide different from an adenosine nucleotide (e.g., a nucleotide that is not an adenosine nucleotide). For example, a poly(A) tail of 100 adenosine nucleotides may have a length of more than 100 nucleotides (comprising 100 adenosine nucleotides and at least one nucleotide, or a stretch of nucleotides, that are different from an adenosine nucleotide). In some embodiments, the poly(A) tail comprises the sequence AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGCAUAUGACUAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA (SEQ ID NO: 5). [1172] The “poly(A) tail,” as used herein, typically relates to RNA. However, in the context of the disclosure, the term likewise relates to corresponding sequences in a DNA molecule (e.g., a “poly(T) sequence”). [1173] The poly(A) tail may comprise about 10 to about 500 adenosine nucleotides, about 10 to about 200 adenosine nucleotides, about 40 to about 200 adenosine nucleotides, or about 40 to about 150 adenosine nucleotides. The length of the poly(A) tail may be at least about 10, 50, 75, 100, 150, 200, 250, 300, 350, 400, 450, or 500 adenosine nucleotides. In some embodiments, the polyA tail may comprise at least 100 adenosine nucleotides. [1174] In some embodiments, the polyA tail may comprise from at least about 70 adenosine nucleotides to at least about 120 adenosine nucleotides. [1175] In some embodiments, the polyA tail may comprise at least about 70, 75, 80, 85, 90, 95, 100, 105, 110, 115 or about 120 adenosine nucleotides. [1176] In some embodiments, the polyA tail may comprise at least about 70 adenosine nucleotides or at least about 100 adenosine nucleotides. [1177] In some embodiments, the polyA tail may comprise at least about 80 adenosine nucleotides or at least 115 adenosine nucleotides. [1178] In some embodiments, the polyA tail may comprise at least about 100 adenosine nucleotides. [1179] In some embodiments where the nucleic acid is an RNA, the poly(A) tail of the nucleic acid may be obtained from a DNA template during RNA in vitro transcription. In some embodiments, the poly(A) tail may be obtained in vitro by common methods of chemical synthesis without being transcribed from a DNA template. In various embodiments, poly(A) tails may be generated by enzymatic polyadenylation of the RNA (after RNA in vitro transcription) using commercially available polyadenylation kits and corresponding protocols, or alternatively, by using immobilized poly(A)polymerases, e.g., using methods and means as described in WO2016/174271. [1180] The nucleic acid may comprise a poly(A) tail obtained by enzymatic polyadenylation, wherein the majority of nucleic acid molecules may comprise about 100 (+/- 20) to about 500 (+/-50) or about 250 (+/-20) adenosine nucleotides. [1181] In some embodiments, the nucleic acid may comprise a poly(A) tail derived from a template DNA and may additionally comprise at least one additional poly(A) tail generated by enzymatic polyadenylation, e.g., as described in WO2016/091391. [1182] In some embodiments, the nucleic acid may comprise at least one polyadenylation signal. [1183] In various embodiments, the nucleic acid may comprise at least one poly(C) sequence. [1184] The term ‘‘poly(C) sequence,” as used herein, is intended to be a sequence of cytosine nucleotides of up to about 200 cytosine nucleotides. In some embodiments, the poly(C) sequence may comprise about 10 to about 200 cytosine nucleotides, about 10 to about 100 cytosine nucleotides, about 20 to about 70 cytosine nucleotides, about 20 to about 60 cytosine nucleotides, or about 10 to about 40 cytosine nucleotides. In some embodiments, the poly(C) sequence may comprise about 30 cytosine nucleotides. Chemical Modification [1185] The mRNA disclosed herein may be modified or unmodified. In some embodiments, the mRNA may comprise at least one chemical modification. In some embodiments, the mRNA disclosed herein may contain one or more modifications that typically enhance RNA stability. Exemplary modifications can include backbone modifications, sugar modifications, or base modifications. In some embodiments, the disclosed mRNA may be synthesized from naturally occurring nucleotides and/or nucleotide analogues (modified nucleotides) including, but not limited to, purines (adenine (A) and guanine (G)) or pyrimidines (thymine (T), cytosine (C), and uracil (U)). [1186] In some embodiments, the disclosed mRNA may be synthesized from modified nucleotide analogues or derivatives of purines and pyrimidines, such as, e.g., 1-methyl- adenine, 2-methyl-adenine, 2-methylthio-N-6-isopentenyl-adenine, N6-methyl-adenine, N6- isopentenyl-adenine, 2-thio-cytosine, 3-methyl-cytosine, 4-acetyl-cytosine, 5-methyl-cytosine, 2,6-diaminopurine, 1-methyl-guanine, 2-methyl-guanine, 2,2-dimethyl-guanine, 7-methyl- guanine, inosine, 1-methyl-inosine, pseudouracil (5-uracil), dihydro-uracil, 2-thio-uracil, 4-thio- uracil, 5-carboxymethylaminomethyl-2-thio-uracil, 5-(carboxyhydroxymethyl)-uracil, 5-fluoro- uracil, 5-bromo-uracil, 5-carboxymethylaminomethyl-uracil, 5-methyl-2-thio-uracil, 5-methyl- uracil, N-uracil-5-oxy acetic acid methyl ester, 5-methylaminomethyl-uracil, 5- methoxyaminomethyl-2-thio-uracil, 5’-methoxycarbonylmethyl-uracil, 5-methoxy-uracil, uracil- 5-oxyacetic acid methyl ester, uracil-5-oxyacetic acid (v), 1-methyl-pseudouracil, queosine, β- D-mannosyl-queosine, phosphoramidates, phosphorothioates, peptide nucleotides, methylphosphonates, 7-deazaguanosine, 5-methylcytosine, and inosine, and combinations thereof. [1187] In some embodiments, the disclosed mRNA may comprise at least one chemical modification including, but not limited to, pseudouridine, N1-methylpseudouridine, 2- thiouridine, 4’-thiouridine, 5-methylcytosine, 2-thio-l-methyl-1-deaza-pseudouridine, 2-thio-l- methyl-pseudouridine, 2-thio-5-aza-uridine, 2-thio-dihydropseudouridine, 2-thio- dihydrouridine, 2-thio-pseudouridine, 4-methoxy-2-thio-pseudouridine, 4-methoxy- pseudouridine, 4-thio-l-methyl-pseudouridine, 4-thio-pseudouridine, 5-aza-uridine, dihydropseudouridine, 5-methyluridine, 5-methyluridine, 5-methoxyuridine, and 2’-O-methyl uridine. [1188] In some embodiments, the chemical modification may be selected from the group consisting of pseudouridine, N1-methylpseudouridine, 5-methylcytosine, 5- methoxyuridine, and a combination thereof. [1189] In some embodiments, the RNA may comprise at least one N1- methylpseudouridine. [1190] In some embodiments, the chemical modification may comprise N1- methylpseudouridine. Typically, the chemical modification may comprise N1- methylpseudouridine in place of every uridine, i.e. 100% of U residues are N1- methylpseudouridine. [1191] In some embodiments, at least from about 20% to about 100%, or from about 30% to about 95%, or from about 40% to about 90%, or from about 50% to about 85%, or from about 60% to about 80%, or from about 70%to about 80% the uracil nucleotides in the RNA may be modified nucleotide analogues. [1192] In some embodiments, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% of the uracil nucleotides in the mRNA may be chemically modified. [1193] In some embodiments, at least from about 20% to about 100%, or from about 30% to about 95%, or from about 40% to about 90%, or from about 50% to about 85%, or from about 60% to about 80%, or from about 70%to about 80% the uracil nucleotides in the ORF may be modified nucleotide analogues. [1194] In some embodiments, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% of the uracil nucleotides in the ORF may be chemically modified. [1195] The preparation of such analogues is described, e.g., in U.S. Pat. No. 4,373,071, U.S. Pat. No.4,401,796, U.S. Pat. No.4,415,732, U.S. Pat. No.4,458,066, U.S. Pat. No.4,500,707, U.S. Pat. No.4,668,777, U.S. Pat. No.4,973,679, U.S. Pat. No.5,047,524, U.S. Pat. No.5,132,418, U.S. Pat. No.5,153,319, U.S. Pat. No.5,262,530, and U.S. Pat. No. 5,700,642, which are incorporated by reference. mRNA Synthesis [1196] The mRNAs disclosed herein may be synthesized according to any of a variety of methods. For example, mRNAs according to the present disclosure may be synthesized via in vitro transcription (IVT). Some methods for in vitro transcription may be described, e.g., in Geall et al. (2013) Semin. Immunol.25(2): 152-159; Brunelle et al. (2013) Methods Enzymol. 530:101-14. Briefly, IVT is typically performed with a linear or circular DNA template containing a promoter, a pool of ribonucleotide triphosphates, a buffer system that may include DTT and magnesium ions, an appropriate RNA polymerase (e.g., T3, T7, or SP6 RNA polymerase), DNase I, pyrophosphatase, and/or RNase inhibitor. The exact conditions may vary according to the specific application. The presence of these reagents is generally undesirable in a final mRNA product and these reagents can be considered impurities or contaminants which can be purified or removed to provide a clean and/or homogeneous mRNA that may be suitable for therapeutic use. While mRNA provided from in vitro transcription reactions may be desirable in some embodiments, other sources of mRNA can be used according to the instant disclosure including wild-type mRNA produced from viruses, bacteria, parasites, fungi, plants, and/or animals. Self-Replicating RNA, Trans-Replicating RNA and Non-Replicating RNA [1197] Typically, the nucleic acid molecules described herein are non-replicating RNAs. However, the nucleic acid molecules described herein may alternatively be self- replicating RNAs or trans-replicating RNAs. Self-replicating RNA [1198] Self-replicating (or self-amplifying) RNA can be produced by using replication elements derived from, e.g., alphaviruses, and substituting the structural viral proteins with a nucleotide sequence encoding a protein of interest (e.g., a polypeptide described herein). A self-replicating RNA is typically a positive-strand molecule which can be directly translated after delivery to a cell, and this translation provides an RNA-dependent RNA polymerase which then produces both antisense and sense transcripts from the delivered RNA. Thus, the delivered RNA leads to the production of multiple daughter RNAs. These daughter RNAs, as well as collinear subgenomic transcripts, may be translated themselves to provide in situ expression of an encoded antigen, or may be transcribed to provide further transcripts with the same sense as the delivered RNA which are translated to provide in situ expression of the antigen. The overall result of this sequence of transcriptions is a large amplification in the number of the introduced replicon RNAs and so the encoded antigen becomes a major polypeptide product of the cells. [1199] One suitable system for achieving self-replication in this manner is to use an alphavirus-based replicon. These replicons are positive stranded (positive sense-stranded) RNAs which lead to translation of a replicase (or replicase-transcriptase) after delivery to a cell. The replicase is translated as a polyprotein which auto-cleaves to provide a replication complex which creates genomic-strand copies of the positive-strand delivered RNA. These negative (-)-stranded transcripts can themselves be transcribed to give further copies of the positive-stranded parent RNA and also to give a subgenomic transcript which encodes the antigen. Translation of the subgenomic transcript thus leads to in situ expression of the antigen by the infected cell. Suitable alphavirus replicons can use a replicase from a Sindbis virus, a Semliki forest virus, an eastern equine encephalitis virus, a Venezuelan equine encephalitis virus, etc. Mutant or wild-type virus sequences can be used, e.g., the attenuated TC83 mutant of VEEV has been used in replicons, see the following reference: WO2005/113782, incorporated herein by reference. [1200] In one embodiment, each self-replicating RNA described herein may encode (i) an RNA-dependent RNA polymerase which can transcribe RNA from the self-replicating RNA molecule and (ii) a protein antigen. The polymerase can be an alphavirus replicase, e.g., comprising one or more of alphavirus proteins nsP1, nsP2, nsP3, and nsP4. Whereas natural alphavirus genomes encode structural virion proteins in addition to the non-structural replicase polyprotein, in certain embodiments, the self-replicating RNA molecules do not encode alphavirus structural proteins. Thus, the self-replicating RNA can lead to the production of genomic RNA copies of itself in a cell, but not to the production of RNA-containing virions. The inability to produce these virions means that, unlike a wild-type alphavirus, the self-replicating RNA molecule cannot perpetuate itself in infectious form. The alphavirus structural proteins which are necessary for perpetuation in wild-type viruses are absent from self-replicating RNAs of the present disclosure and their place is taken by gene(s) encoding the immunogen of interest, such that the subgenomic transcript encodes the immunogen rather than the structural alphavirus virion proteins. Self-replicating RNA are described in further detail in WO2011005799, incorporated herein by reference. Trans-replicating RNA [1201] Trans-replicating (or trans-amplifying) RNA possess similar elements as the self-replicating RNA described above. However, with trans replicating RNA, two separate RNA molecules are used. A first RNA molecule encodes for the RNA replicase described above (e.g., the alphavirus replicase) and a second RNA molecule encodes for the protein of interest (e.g., a polypeptide described herein). The RNA replicase may replicate one or both of the first and second RNA molecule, thereby greatly increasing the copy number of RNA molecules encoding the protein of interest. Trans replicating RNA are described in further detail in WO2017162265, incorporated herein by reference. Non-replicating RNA [1202] Non-replicating (or non-amplifying) RNA is an RNA without the ability to replicate itself. Ratio/doses [1203] In some embodiments, the nucleic acid and the water-soluble polyanionic polymer may be present in w/w ratio from about 1:4000 to about 1:25, or from about 1:2000 to about 1:50, or from 1:1000 to about 1:100, or from about 1:800 to about 1:200, or at about 1:500. [1204] In some embodiments, the nucleic acid and the water-soluble polyanionic polymer may be present in w/w ratio of about 1:4000, 1:3500, 1:3000, 1:2500, 1:2000, 1:1500, 1:1000, 1:800, 1:600, 1:500, 1:400, 1:200, 1:100, 1:90, 1:80, 1:70, 1:60, 1:50, 1:45, 1:40, 1:35, 1:30, or about 1:25. [1205] In some embodiments, the water-soluble polyanionic polymer may be present in a range of from about 0.1 mg to about 4 mg, or from about 0.2 mg to about 3 mg, or from about 0.3 mg to about 2.5 mg, or from about 0.4 mg to about 2.0 mg, or from about 0.5 mg to about 1.8 mg, or from about 0.6 mg to about 1.5 mg, or from about 0.8 mg to about 1.2 mg, or at about 1.0 mg per dose of said composition. [1206] In some embodiments, the water-soluble polyanionic polymer may be present at about 0.1 mg, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.5, 2.8, 3.0, 3.5, or at about 4.0 mg per dose of said composition. [1207] In some embodiments, the water-soluble polyanionic polymer may be present at about 0.1 mg, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 mg per dose of said composition. Antigens [1208] An antigen encoded by a nucleic acid of the disclosure may be suitable to be used for the treatment or prevention of various diseases that may affect humans or animals other than humans. [1209] An antigen can be from bacteria, viruses, parasites or from cancer cells. [1210] Viral antigens may be selected from the group of viruses consisting of: poliovirus, rabies virus, hepatitis A, hepatitis B, hepatitis C, yellow fever virus, varicella zoster virus (VZV), measles virus, mumps virus, rubella virus, Japanese encephalitis virus, influenza virus, norovirus, rhinovirus, respiratory syncytial virus (RSV), human metapneumovirus (hMPV), Parainfluenza Virus (PIV), sars-cov-1, sars-cov-2, herpes simplex virus, papilloma virus, cytomegalovirus virus, rotavirus, West Nile virus, dengue virus, chikungunya virus, Epstein-Barr virus (EBV), HIV (AIDS), and combinations thereof. [1211] Bacterial antigens may be selected from the group of bacteria consisting of: Acetobacter aurantius, Acinetobacter baumannii, Actinomyces israelii, Agrobacterium radiobacter, Agrobacterium tumefaciens, Anaplasma phagocytophilum, Azorhizobium caulinodans, Azotobacter vinelandii, Bacillus anthracis, Bacillus brevis, Bacillus cereus, Bacillus fusiformis, Bacillus licheniformis, Bacillus megaterium, Bacillus mycoides, Bacillus stearothermophilus, Bacillus subtilis, Bacillus Thuringiensis, Bacteroides fragilis, Bacteroides gingivalis, Bacteroides melaninogenicus, Bartonella henselae, Bartonella Quintana, Bordetella bronchiseptica, Bordetella pertussis, Borrelia burgdorferi. Brucella abortus, Brucella melitensis, Brucella suis, Burkholderia mallei, Burkholderia pseudomallei, Burkholderia cepacia, Calymmatobacterium granulomatis, Campylobacter coli, Campylobacter fetus, Campylobacter jejuni, Campylobacter pylori, Chlamydia trachomatis, Chlamydophila pneumoniae, Chlamydophila psittaci, Clostridium botulinum, Clostridium difficile, Clostridium perfringens, Clostridium tetani, Corynebacterium diphtheriae, Corynebacterium fusiforme, Coxiella burnetii, Cutibacterium acnes, Cutibacterium avidum, Cutibacterium granulosum, Cutibacterium namnetense, Cutibacterium humerusii, Ehrlichia chaffeensis, Enterobacter cloacae, Enterococcus avium, Enterococcus durans, Enterococcus faecalis, Enterococcus faecium, Enterococcus galllinarum, Enterococcus maloratus, Escherichia coli, Francisella tularensis, Fusobacterium nucleatum, Gardnerella vaginalis, Haemophilus ducreyi, Haemophilus influenzae, Haemophilus parainfluenzae, Haemophilus pertussis, Haemophilus vaginalis, Helicobacter pylori, Klebsiella pneumoniae, Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus casei, Lactococcus lactis, Legionella pneumophila, Listeria monocytogenes, Methanobacterium extroquens, Microbacterium multiforme, Micrococcus luteus, Moraxella catarrhalis, Mycobacterium avium, Mycobacterium bovis, Mycobacterium diphtheriae, Mycobacterium intracellulare, Mycobacterium leprae, Mycobacterium lepraemurium, Mycobacterium phlei, Mycobacterium smegmatis, Mycobacterium tuberculosis, Mycoplasma fermentans, Mycoplasma genitalium, Mycoplasma hominis, Mycoplasma penetrans, Mycoplasma pneumoniae, Neisseria gonorrhoeae, Neisseria meningitidis, Pasteurella multocida, Pasteurella tularensis, Peptostreptococcus, Porphyromonas gingivalis, Prevotella melaninogenica, Propionibacterium acnes, Pseudomonas aeruginosa, Rhizobium radiobacter, Rickettsia prowazekii, Rickettsia psittaci, Rickettsia quintana, Rickettsia rickettsii, Rickettsia trachomae, Rochalimaea henselae, Rochalimaea quintana, Rothia dentocariosa, Salmonella enteritidis, Salmonella typhi, Salmonella typhimurium, Serratia marcescens, Shigella dysenteriae, Spirillum volutans, Staphylococcus aureus, Staphylococcus epidermidis, Stenotrophomonas maltophilia, Streptococcus agalactiae, Streptococcus avium, Streptococcus bovis, Streptococcus cricetus, Streptococcus faceium, Streptococcus faecalis, Streptococcus ferus, Streptococcus gallinarum, Streptococcus lactis, Streptococcus mitior, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus rattus, Streptococcus salivarius, Streptococcus sanguis, Streptococcus sobrinus, Treponema pallidum, Treponema denticola, Vibrio cholerae, Vibrio comma, Vibrio parahaemolyticus, Vibrio vulnificus, Viridans streptococci, Wolbachia, Yersinia enterocolitica, Yersinia pestis, Yersinia pseudotuberculosis, and combinations thereof. [1212] Parasitic antigens may be selected from the group of parasites consisting of: Plasmodium spp., Leishmania spp., Trypanosoma spp., Schistosome spp. [1213] Cancer antigens are molecules expressed on the surface of cancer cells or secreted into the bloodstream which can be recognized and targeted by the immune system. These antigens are often absent or present at much lower levels on healthy cells. [1214] Cancer antigens may be selected from the group consisting of: HER2/neu, EGFR (Epidermal Growth Factor Receptor), BRAF, carcinoembryonic antigen (CEA), MAGE- A, NY-ESO-1. Vaccines & kits-of-parts [1215] In some embodiments, the disclosure relates to a composition comprising: [1216] - at least one water-soluble polyanionic polymer, [1217] - at least one nucleic acid carrier, and [1218] - at least one nucleic acid. [1219] In some embodiments, the at least one water-soluble polyanionic polymer, the at least one nucleic acid carrier and/or the at least one nucleic acid are as disclosed herein. [1220] In some embodiments, the water-soluble polyanionic polymer is a polyacrylic acid polymer, or a pharmaceutically acceptable thereof. [1221] In some embodiments, the nucleic acid carrier comprises at least one cationic, or ionizable cationic, lipid. In some embodiments, the nucleic acid carrier is a lipid nanoparticle (LNP). [1222] In some embodiments, the nucleic acid encodes at least one antigen. In some embodiments, the nucleic acid is an mRNA. [1223] In some embodiments, the composition comprises at least one nucleic acid, e.g. an mRNA, encoding an antigen from an influenza virus. [1224] In some embodiments, the composition comprises at least one nucleic acid, e.g. an mRNA, encoding an antigen from Porphyromonas gingivalis. [1225] In some embodiments, the composition comprises at least one nucleic acid, e.g. an mRNA, encoding an antigen from an Epstein-Barr virus. [1226] In some embodiments, the composition comprises at least two different nucleic acids, e.g. mRNAs, encoding at least two different antigens. In some embodiments, the two different antigens are from the same virus or bacterium. In some embodiments, the two different antigens are from different viruses or bacteria. The at least two nucleic acids, e.g. mRNAs, may be present in equal quantities, or in different ratios, for example 1:1 to 1:20, or 1:1: to 1:10 ratio, such as 1:1, 1:2, 1:3 or 1:4. ratio [1227] In some embodiments, the composition comprises at least two different nucleic acids, e.g. mRNAs, encoding an antigen from RSV (e.g. an RSV pre-F antigen) and an antigen from hMPV (e.g. an hMPV pre-F antigen). In some embodiments, these two nucleic acids, e.g. mRNAs, comprise a coding sequence of SEQ ID NO:7 and a coding sequence of SEQ ID NO:8, respectively, potentially flanked in 5’ by the 5’UTR of SEQ ID NO: 1 and in 3’ by the 3’UTR of SEQ ID NO: 2. In some embodiments, these two nucleic acids, e.g. mRNAs, are in 1:1 to 1:10 RSV:hMPV ratio, for example in 1:1, 1:2, 1:3 or 1:4 RSV:hMPV ratio. [1228] In some embodiments, the composition comprises at least one nucleic acid, e.g. mRNA, encoding an antigen from RSV (e.g. an RSV pre-F antigen), an antigen from hMPV (e.g. an hMPV pre-F antigen) and/or an antigen from PIV (e.g. an antigen from PIV3). In other embodiments, the composition comprises at least two nucleic acids, e.g. mRNAs, encoding an antigen from RSV (e.g. an RSV pre-F antigen), an antigen from hMPV (e.g. an hMPV pre-F antigen) and/or an antigen from PIV (e.g. an antigen from PIV3). In still other embodiments, the composition comprises at least three nucleic acids, e.g. mRNAs, encoding an antigen from RSV (e.g. an RSV pre-F antigen), an antigen from hMPV (e.g. an hMPV pre-F antigen) and an antigen from PIV (e.g. an antigen from PIV3). [1229] In some embodiments, the disclosure relates to a composition comprising: [1230] - at least one water-soluble polyanionic polymer, wherein said water-soluble polyanionic polymer is a polyacrylic acid polymer, or a pharmaceutically acceptable thereof, [1231] - at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, wherein said nucleic acid carrier is a lipid nanoparticle (LNP), and [1232] - at least one nucleic acid encoding at least one antigen, wherein said nucleic acid is an mRNA. [1233] In some embodiments, the disclosure relates to a vaccine comprising a prophylactically effective amount or a therapeutically effective amount of the immunogenic composition according to the disclosure. [1234] In some embodiments, the disclosure relates to a kit-of-parts comprising at least a first container and at least a second container, wherein: [1235] the first container comprises a first composition comprising at least one water- soluble polyanionic polymer, [1236] - the second container comprises a second composition comprising at least one nucleic acid carrier and at least one nucleic acid. [1237] In some embodiments, the at least one water-soluble polyanionic polymer, the at least one nucleic acid carrier and/or the at least one nucleic acid are as disclosed herein. [1238] In some embodiments, the at least one water-soluble polyanionic polymer, the at least one nucleic acid carrier and/or the at least one nucleic acid are as disclosed herein. [1239] In some embodiments, the water-soluble polyanionic polymer is a polyacrylic acid polymer, or a pharmaceutically acceptable thereof. [1240] In some embodiments, the nucleic acid carrier comprises at least one cationic, or ionizable cationic, lipid. In some embodiments, the nucleic acid carrier is a lipid nanoparticle (LNP). [1241] In some embodiments, the nucleic acid encodes at least one antigen. In some embodiments, the nucleic acid is an mRNA. [1242] In some embodiments, the disclosure relates to a kit-of-parts comprising at least a first container and at least a second container, wherein: [1243] - the first container comprises a first composition comprising at least one water- soluble polyanionic polymer, and [1244] - the second container comprises a second composition comprising at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, and at least one nucleic acid encoding at least one antigen. [1245] The at least one water-soluble polyanionic polymer, the at least one cationic, or ionizable cationic, lipid, and the at least one nucleic acid encoding at least one antigen of the composition, vaccine and kit-of-parts are as above disclosed. Compositions for uses [1246] In some embodiments, the disclosure relates to an immunogenic composition for use in an immunization method. [1247] In some embodiments, the immunization method is for eliciting an immune response against an antigen in an individual in need thereof. [1248] In some embodiments, the immunization method comprises a step of administering the immunogenic composition, for example by intramuscular injection. [1249] In some embodiments, the disclosure relates to an immunogenic composition for use in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, said immunogenic composition comprising at least one water- soluble polyanionic polymer, at least one nucleic acid carrier, and at least one nucleic acid encoding at least said antigen. [1250] In some embodiments, the immune response is a predominantly Th1 response or Th1 skewed immune response. [1251] In some embodiments, the immune response is specific to the antigen. [1252] In some embodiments, the immunization method is for inducing an immune response with an antigen-encoding nucleic acid (e.g. mRNA) dose-sparing effect. [1253] In some embodiments, the disclosure relates to an immunogenic composition for use in an immunization method in an individual in need thereof, said immunogenic composition comprising at least one water-soluble polyanionic polymer, at least one nucleic acid carrier, and at least one nucleic acid encoding at least said antigen, wherein said composition allowing obtaining an antigen-encoding nucleic acid dose-sparing effect. [1254] In some embodiments, the composition of the disclosure may comprise an amount of antigen-encoding nucleic acid at least about 2 times lower than the amount of antigen-encoding nucleic acid of an immunogenic composition comprising the same nucleic acid carrier and the same nucleic acid and inducing a similar or comparable immune response in absence of the water-soluble polyanionic polymer. [1255] In some embodiments, the composition of the disclosure may comprise an amount of antigen-encoding nucleic acid at least about 10 times lower than the amount of antigen-encoding nucleic acid of an immunogenic composition comprising the same nucleic acid carrier and the same nucleic acid and inducing a similar or comparable immune response in absence of the water-soluble polyanionic polymer. [1256] In some embodiments, the composition of the disclosure may comprise an amount of antigen-encoding nucleic acid at least about 20 times lower than the amount of antigen-encoding nucleic acid of an immunogenic composition comprising the same nucleic acid carrier and the same nucleic acid and inducing a similar or comparable immune response in absence of the water-soluble polyanionic polymer. [1257] In some embodiments, the composition of the disclosure may comprise an amount of antigen-encoding nucleic acid from at least about 2 to about 20 times, or from about 4 to about 16 times, or from about 5 to about 14 times, or from about 5 to about 12 times, or from about 8 to about 10 times lower than the amount of antigen-encoding nucleic acid of an immunogenic composition comprising the same nucleic acid carrier and the same nucleic acid and inducing a similar or comparable immune response in absence of the water-soluble polyanionic polymer. [1258] In some embodiments, the composition of the disclosure may comprise an amount of antigen-encoding nucleic acid at least about 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or about 20 times lower than the amount of antigen-encoding nucleic acid of an immunogenic composition comprising the same nucleic acid carrier and the same nucleic acid and inducing a similar or comparable immune response in absence of the water-soluble polyanionic polymer. [1259] In some embodiments, the composition of the disclosure may comprise an amount of antigen-encoding nucleic acid at least about 2, 3, 4, 5, 6, 7, 8, 9, or about 10 times lower than the amount of antigen-encoding nucleic acid of an immunogenic composition comprising the same nucleic acid carrier and the same nucleic acid and inducing a similar or comparable immune response in absence of the water-soluble polyanionic polymer. [1260] In some embodiments, the disclosure relates to an immunogenic composition for use in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, said immunogenic composition comprising at least one water- soluble polyanionic polymer, at least one nucleic acid carrier, and at least one nucleic acid encoding at least said antigen, wherein said composition allowing obtaining an antigen- encoding nucleic acid dose-sparing effect, wherein the antigen-encoding nucleic acid dose- sparing effect allows the use in said composition of less than about one-tenth of the amount of said nucleic acid required for eliciting said immune response in absence of said water-soluble polyanionic polymer. [1261] In some embodiments, the antigen-encoding nucleic acid dose-sparing effect allows the use in said composition of less than about ½, 1/3^rd, ¼ ^th, 1/5^th, 1/6 ^th, 1/7 ^th, 1/8 ^th, 1/9 ^th, or about 1/10 ^th of the amount of said nucleic acid required for eliciting said immune response in absence of said water-soluble polyanionic polymer. [1262] In some embodiments, the antigen-encoding nucleic acid dose-sparing effect allows the use in said composition of from about ½ to about 1/20^th, or from about 1/4^th to about 1/15^th, or from about 1/5^th to about 1/12^th, or from about 1/8^th to about 1/10^th, of the amount of said nucleic acid required for eliciting said immune response in absence of said water-soluble polyanionic polymer. [1263] In some embodiments, the disclosure relates to a kit-of-parts for use in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, said kit-of-parts comprising at least a first container and at least a second container, wherein: [1264] - the first container comprises a first composition comprising at least one water- soluble polyanionic polymer, [1265] - the second container comprises a second composition comprising least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen, [1266] and wherein the immunization method comprises administering to said individual, e.g. by intramuscular injection, the first and second compositions simultaneously, sequentially or separately. [1267] In some embodiments, the at least one water-soluble polyanionic polymer, the at least one cationic, or ionizable cationic, lipid, and the at least one nucleic acid encoding at least one antigen are as disclosed herein. Dose sparing, uses and methods [1268] The dosage of a composition of the disclosure may depend on the species, breed, age, size, vaccination history, and health status of the individual to be vaccinated. Other factors like antigen concentration, additional composition components, and route of administration (i.e., subcutaneous, intradermal, oral, intramuscular or intravenous administration) may also impact the effective dosage. [1269] The dosage of a composition to administer is determinable based on the antigen concentration of the composition, the route of administration, and the age and condition of the individual to be vaccinated. Each batch of antigen may be individually calibrated. Alternatively, methodical immunogenicity trials of different dosages, as well as LD50 studies and other screening procedures can be used to determine effective dosage for a composition of the disclosure without undue experimentation. [1270] A suitable dosage provides at least a partial protective effect against an infection, as evidenced by a reduction in the mortality and morbidity associated with the infection. [1271] The appropriate volume can be likewise easily ascertained by one of ordinary skill in the art. The volume of a dose may be from about 0.1 ml to about 1.0 ml and, for example, from about 0.3 ml to about 0.5 ml. [1272] Repeated administrations of a composition of the disclosure may be carried out at periodic time intervals to enhance the immune response initially or when a long period of time has elapsed since the last dose. In one embodiment of the present disclosure, the composition is administered as a parenteral injection (i.e., subcutaneously, intradermally, or intramuscularly). The composition may be administered as one single dose or, in alternate embodiments, administered in repeated doses of from about two to about five doses given at intervals of about two to about six weeks, preferably from about two to about five weeks. However, one of skill in the art will recognize that the number of doses and the time interval between vaccinations depends on a number of factors including, but not limited to, the age of the individual vaccinated; the condition of the individual; the route of immunization; amount of antigen available per dose; and the like. For initial vaccination, the period will generally be longer than a week and preferably will be between about two to about five weeks. For previously vaccinated individuals, a booster vaccination at about 6-months, 1-year, 2, 3-, 4-, 5-, or 10-years interval may be performed. [1273] In some embodiments, the disclosure relates to a use of a water-soluble polyanionic polymer in an immunogenic composition for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, said immunogenic composition further comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least said antigen. [1274] In some embodiments, the disclosure relates to a use of a water-soluble polyanionic polymer in an immunogenic composition for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, said immunogenic composition comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least said antigen, wherein the antigen-encoding nucleic acid dose-sparing effect allows the use in said composition of less than an half of the amount of said nucleic acid required for eliciting said immune response in absence of said water-soluble polyanionic polymer. [1275] In some embodiments, the disclosure relates to a use of a water-soluble polyanionic polymer in an immunogenic composition for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, said immunogenic composition comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least said antigen, wherein the antigen-encoding nucleic acid dose-sparing effect allows the use in said composition of less than a fifth of the amount of said nucleic acid required for eliciting said immune response in absence of said water-soluble polyanionic polymer. [1276] In some embodiments, the disclosure relates to a use of a water-soluble polyanionic polymer in an immunogenic composition for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, said immunogenic composition comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least said antigen, wherein the antigen-encoding nucleic acid dose-sparing effect allows the use in said composition of less than a tenth of the amount of said nucleic acid required for eliciting said immune response in absence of said water-soluble polyanionic polymer. [1277] In some embodiments, the disclosure relates to a use of a water-soluble polyanionic polymer in combination with a formulation comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen for obtaining an antigen- encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response against said antigen in an individual in need thereof. [1278] In some embodiments, the disclosure relates to a use of a water-soluble polyanionic polymer in an immunogenic composition for adjuvanting said immunogenic composition, the immunogenic composition further comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen. [1279] In some embodiments, the disclosure relates to a use of a water-soluble polyanionic polymer as adjuvant in an immunogenic composition, the immunogenic composition further comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen. [1280] In some embodiments, the disclosure relates to a use of a water-soluble polyanionic polymer in the manufacture of an immunogenic composition, the composition being for use in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, the composition comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least said antigen. [1281] In some embodiments, the disclosure relates to a use of a water-soluble polyanionic polymer as adjuvant in the manufacture of an immunogenic composition, the composition being for use in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, the composition comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least said antigen. [1282] In some embodiments, the disclosure relates to a use of a water-soluble polyanionic polymer in the manufacture of a kit-of-parts, the kit-of-parts being for use in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, the kit-of-parts comprising at least a first container and at least a second container, wherein: [1283] - the first container comprises a first composition comprising at least one water- soluble polyanionic polymer, [1284] - the second container comprises a second composition comprising least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen, [1285] and wherein the immunization method comprises administering to said individual, e.g. by intramuscular injection, the first and second compositions simultaneously, sequentially or separately. [1286] In some embodiments, the disclosure relates to a use of a combination in the manufacture of an immunogenic composition, the composition being for use in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, the combination comprising at least one water-soluble polyanionic polymer, at least one nucleic acid carrier, and at least one nucleic acid encoding at least said antigen. [1287] In some embodiments, the disclosure relates to a method for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response against said antigen in an individual in need thereof, the immunization method comprising a step of administering to said individual, e.g. by intramuscular injection, an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water-soluble polyanionic polymer. [1288] In some embodiments, the disclosure relates to a method for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response against said antigen in an individual in need thereof, the immunization method comprising a step of administering to said individual, e.g. by intramuscular injection, an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water-soluble polyanionic polymer, wherein the antigen-encoding nucleic acid dose-sparing effect allows the use in said composition of less than one-tenth of the amount of said nucleic acid required for eliciting said immune response in absence of said water-soluble polyanionic polymer. [1289] In some embodiments, the disclosure relates to a method for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method for eliciting an immune response against an antigen in an individual in need thereof, the immunization method comprising administering to said individual, e.g. by intramuscular injection, a combination comprising a water-soluble polyanionic polymer with a formulation comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen. [1290] In some embodiments, the disclosure relates to a method of adjuvanting an immune response in an immunization method for eliciting said immune response against an antigen in an individual in need thereof, the immunization method comprising a step of administering to said individual, e.g. by intramuscular injection, an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water-soluble polyanionic polymer. [1291] In some embodiments, the disclosure relates to a method of adjuvanting an immune response in an immunization method for eliciting said immune response against an antigen in an individual in need thereof, the immunization method comprising a step of administering to said individual, e.g. by intramuscular injection, an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water-soluble polyanionic polymer, the method comprising a step of manufacturing said immunogenic composition by a method comprising at least a step adding said one water-soluble polyanionic polymer to a formulation comprising said at least one nucleic acid carrier and said at least one nucleic acid encoding at least said antigen. [1292] In some embodiments, the disclosure relates to a method for manufacturing an immunogenic composition, the method comprising at least a step of adding at least one water- soluble polyanionic polymer to a formulation comprising said at least one nucleic acid carrier and said at least one nucleic acid encoding at least one antigen. [1293] In some embodiments, the disclosure relates to a method for manufacturing a kit-of-parts, the method comprising at least a step of preparing at least a first container and a step of preparing at least a second container, wherein: [1294] - the first container comprises a first composition comprising at least one water- soluble polyanionic polymer, [1295] - the second container comprises a second composition comprising least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen. [1296] In some embodiments, the disclosure relates to a method for eliciting an immune response against an antigen in an individual in need thereof, the method comprising at least a step of administering to said individual, e.g. by intramuscular injection, an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water-soluble polyanionic polymer. [1297] In some embodiments, the disclosure relates to a method for eliciting a prophylactic immune response against an antigen in an individual in need thereof, the method comprising at least a step of administering to said individual, e.g. by intramuscular injection, an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water-soluble polyanionic polymer. [1298] In some embodiments, the disclosure relates to a method for eliciting a therapeutic immune response against an antigen in an individual in need thereof, the method comprising at least a step of administering to said individual, e.g. by intramuscular injection, an immunogenic composition comprising at least one nucleic acid carrier, at least one nucleic acid encoding at least said antigen, and at least one water-soluble polyanionic polymer. [1299] In some embodiments, the disclosure relates to a method for eliciting an immune response against an antigen in an individual in need thereof, the method comprising at least a step of administering to an individual in need thereof, e.g. by intramuscular injection, at least a first composition and at least a second composition from a kit-of-parts, wherein said kit-of-parts comprises a first container and at least a second container, wherein: [1300] - the first container comprises said first composition, said first composition comprising at least one water-soluble polyanionic polymer, [1301] - the second container comprises a second composition, said composition comprising least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen, [1302] and wherein the step of administering to said individual comprises a simultaneous, a sequential or a separate administration of said first and said second compositions. [1303] In some embodiments, the immune response is a predominantly Th1 response or Th1 skewed immune response. [1304] In some embodiments, the immune response is specific to the antigen. [1305] In some embodiments, the at least one water-soluble polyanionic polymer, the at least one cationic, or ionizable cationic, lipid, and the at least one nucleic acid encoding at least one antigen are as above disclosed. [EXAMPLES] [1306] The following examples illustrate the embodiments of the disclosure that are presently best known. However, it is to be understood that the following are only exemplary or illustrative of the application of the principles of the present disclosure. Numerous modifications and alternative compositions, methods, and systems may be devised by those skilled in the art without departing from the spirit and scope of the present disclosure. Thus, while the present disclosure has been described above with particularity, the following examples provide further detail in connection with what are presently deemed to be the most practical and preferred embodiments of the disclosure. Example 1: Preparation of adjuvanted LNP/mRNA Preparation of the SPA09 adjuvant (polyacrylic acid (PAA) polymer) [1307] Polyacrylic acid (PAA) sodium salt was obtained from POLYSCIENCES (Eppelheim, Germany) in the form of concentrated solution in water for injection, 10% w/w, product code 14137. The commercial solution was then diafiltered upon receipt into PBS pH 7.4 on 50 kDa Pellicon 2 PES diafiltration cassettes (MERCK-MILLIPORE, Molsheim, France). At this stage, the concentration and molecular weight of PAA was determined by high performance size exclusion chromatography (HPSEC). The diafiltered PAA solution was then diluted to 8 mg/mL into phosphate buffered saline (PBS pH 7.4), sterilized by filtration through 0.2 μm MILLIPORE Express SHC(PES) membranes and kept stored at 4°C. Characterizations of the SPA09 adjuvant [1308] Appearance was visually assessed (physical state, color, clarity), in order to ensure consistency of the product. Acceptance criterion was a colorless limpid solution. [1309] pH was assessed by potentiometric determination. [1310] PAA concentration, weight average molecular weight (Mw), number average molecular weight (Mn), Mark Houwink slope, intrinsic viscosity and hydrodynamic radius were determined by high performance size exclusion chromatography (HPSEC). Briefly, HPSEC analyses were performed on a VISCOTEK GPCmax VE2501 system (MALVERN INSTRUMENTS, MALVERN, UK) comprising a HPLC pump with built-in degasser and autosampler with a 100 µl injection loop. The system was equipped with a VISCOTEK TDA 302 detector with right angle laser light scattering (RALLS), refractive index (RI), and viscosity (VIS) detection. OMNISEC 4.7 software was used for the acquisition and analysis of SEC data. The detectors were calibrated with a 100 kDa pullulan standard (MALVERN INSTRUMENTS) in PBS. For PAA characterization, the system was equipped with a TSKgel G6000 PWXL column, 13 µm, 7.8mm ID x 30 cm L (TOSOH BIOSCIENCES). The mobile phase consisted of NaCl 0.9%. The flow rate was 0.6 ml/min at a column temperature of 30°C. Samples were injected at a concentration of 1 mg/ml under a volume of 100 µl. [1311] Polydispersity Index (PI) was calculated as the ratio of Mw/Mn. [1312] Content of residual sodium acrylate (monomer) and sodium persulfate (initiator of polymerization and process-related impurity) were determined by ionic chromatography. Bacterial and fungal sterility tests were performed by membrane filtration. [1313] SPA09 used for in vivo studies was always controlled for low endotoxin content (< 5 IU/ ml) by using ENDOSAFE® cartridges and an ENDOSAFE®-PTSTM spectrophotometer (CHARLES RIVER LABORATORIES INTERNATIONAL, Inc., Wilmington, MA). [1314] Results obtained for the PAA polymer (SPA09) used in the following examples are presented in Table 1 below. [1315] Table 1. Characterization of the PAA polymer (SPA09) used in the examples. Characteristics Results Bacterial and fungal sterility test Conform Appearance Colorless limpid solution pH measurement 7.3 PAA content 7.9 mg/mL Mw 578130 Da Mn 270848 Da PI (Mw/Mn) 2.1 Hydrodynamic radius 33.7 nm Characteristics Results Intrinsic viscosity 4.89dl/g Mark-Houwink slope (a) a = 0.81 Sodium acrylate content < 1 µg/mL Sodium persulfate content < 40 µg/mL Preparation of the LNP/mRNA [1316] Each mRNA comprised a cap1, a 5’UTR from CMV of SEQ ID NO: 1, a coding sequence, a 3’ UTR from hGH of SEQ ID NO: 2, and a polyA tail. In all mRNAs, 100% of uridines were replaced with 1-methyl-pseudouridine. [1317] Each mRNA was encapsulated in lipid nanoparticles (LNPs) composed of four lipids: ionizable (cationic) lipid / DOPE / cholesterol / DMG-PEG, at the molar ratio of 40:30:28.5:1.5. OF-02 or GL-HEPES-E3-E12-DS-4-E10 was used as the ionizable lipid. [1318] LNPs were prepared using a T-mix process. Briefly, lipids were dissolved in ethanol (EtOH) at a final concentration of 9.331 mg/mL and mRNA solution was prepared in Citrate Buffer Saline (CBS at 1mM citrate pH 4.5 and 150 mM sodium chloride).3 mL of the lipid solution and 12 mL of the mRNA solution were loaded respectively in a 5 mL and 20 mL syringe. Using a T-mix system 3/32’’ and pumps, mRNA solution and lipids were mixed at a total flow rate of 250 mL/min (flow rate at 50 mL/min for the lipids and flow rate of 200 mL/min for the mRNA). The mixture was then treated by buffer exchange. First, a dialysis in water:EtOH 80:20 was performed 2h at room temperature (RT), then a second dialysis in water was performed overnight at +4°C. The last step was a concentration to 1 mg/mL mRNA and a buffer exchange in Amicon at +4°C with trehalose 10%. LNPs were then sterile filtered and stored at -80°C. Preparation of the adjuvanted LNP/mRNA [1319] Samples of adjuvanted LNP/mRNA were prepared just before injection to mice. [1320] Briefly, vials of LNP/mRNA (at 1 mg/mL of mRNA) were taken from -80°C and thawed on ice until complete thaw. A visual check of the vials to ensure complete thawing before dilution was performed. Each vial was gently swirled by hand in upright position prior to withdrawing the required volume. LNP/mRNA was first diluted from 1 mg/mL of mRNA to 0.1 mg/mL of mRNA in PBS 1x pH 7.4 to allow pipetting of a higher volume for the preparation. [1321] Appropriate volumes of LNP/mRNA (from solutions at 0.1 mg/mL of mRNA) and of SPA09 (from vials at 8 mg/mL) were then pipetted using a micropipette and added to an appropriate volume of PBS 1x pH 7.4, to obtain appropriate concentrations for the tested doses of mRNA (ranging from 0.1 µg to 2 µg) and SPA09 (ranging from 20 µg to 200 µg) for a 50 µL injection to mice. The resulting formulation was gently mixed by pipetting several times. All the preparations were done in sterile conditions, under a laminar flow cabinet. [1322] pH and osmolality were measured to ensure that the formulations were compatible with in vivo injection. [1323] The formulation was kept on ice during preparation, then kept at least for 15 min at ambient temperature before injection to mice. Example 2: Characterization of adjuvanted LNP/mRNA [1324] The aim of this study was to characterize particle size of LNP/mRNA formulations, before and after mixture with SPA09 adjuvant, in comparison with SPA09 alone. [1325] SPA09 adjuvant, LNP/mRNA and LNP/mRNA adjuvanted with SPA09 were prepared as described in Example 1. In this Example 2, coding sequence in the mRNA was taken from antigen HA from influenza A/Tasmania/503/2020 (H3N2), of SEQ ID NO: 3. The ionizable lipid used in the LNP was OF-02. [1326] Each sample was diluted 10-fold in PBS and analyzed by Dynamic Light Scattering (DLS) using the ZETASIZER NanoZS equipment (MALVERN PANALYTICAL). The diluted sample was loaded into a cuvette and then inserted t into the ZETASIZER instrument. Three measures were performed to obtain a mean size of the particles (Z-average diameter), and polydispersity index (PDI), using cumulant analysis and the autocorrelation function. [1327] As shown in Figure 1, LNP/mRNA + SPA09 adjuvant had a similar particle size compared with LNP/mRNA alone, with a slightly higher polydispersity index (PDI). It should be noted that with the DLS method, small particles in an heterogeneous mixture (such as in LNP/mRNA + SPA09) could not be detected but could impact the PDI. [1328] No aggregation was observed after mixture, allowing the injection of the formulation in vivo. Example 3: Mouse studies to determine hemagglutination inhibition (HI) serum antibody titers and clinical signs Mouse immunizations [1329] Eight BALBc/ByJ mice per group and per dose, aged 7–8 weeks (body weight 18–20 g) at the time of first immunization were obtained from CHARLES RIVER LABORATORIES (Saint Germain sur l’Arbresle, France). As shown in Figure 2, mice received two injections (of 50µL each), three weeks apart, on day 0 (d0) and d21, with the appropriate doses of mRNA in LNPs (alone or with different doses of SPA09) by slow intramuscular (i.m.) administration into the quadriceps muscle region, after shaving of the injected zone and under isoflurane anesthesia. [1330] As negative control group, four mice received two injections three weeks apart, with PBS buffer. As positive control group, eight mice received 4.5 µg of monovalent Flu vaccine A/Tasmania/503/2020 (H3N2) strain derived from VAXIGRIP™, according to the same immunization schedule. [1331] Mice were monitored daily for clinical signs and blood samples were collected on d20 and on (d35 or d42) for antibody response analysis by hemagglutination inhibition assay (HI). Monitoring of clinical signs [1332] Local and systemic clinical signs like oedema, piloerection, rounded back, unsteady state and loss of motility were monitored daily on each animal after each i.m. administration until complete disappearance of the clinical signs or until the end of the study if needed. Reactogenicity results were reported as % of mice in the group displaying at least one, or several clinical signs per day. Hemagglutination inhibitory (HI) antibody titers – HI assay [1333] The Hemagglutination inhibitory (HI) assay was used to assess functional HI antibodies in serum from influenza immunized or infected animals, which can inhibit turkey erythrocytes' agglutination. The protocols were adapted from the WHO laboratory influenza surveillance manual. [1334] Briefly, two-fold serial dilutions of influenza virus (clarified allantoic fluid) A/Tasmania/503/2020 were performed in PBS to calibrate the viral suspension and to obtain 4 HAU (Hemagglutination Unit) in presence of turkey red blood cells (tRBCs) at 0.5% in PBS. Fifty µL of calibrated virus per V shaped well was then added in a 96 well-plate containing 50 µL per well of serial diluted serum (2-fold) in PBS starting from 1:10 and incubated one hour at room temperature. [1335] To inactivate serum non-specific inhibitors, each serum was treated with a receptor-destroying enzyme (RDE) (neuraminidase from Vibrio cholerae –Type III - SIGMA ALDRICH N7885). Briefly, 10 mU/mL of RDE was added to each serum and then incubated for 18h at 37°C, followed by 1h inactivation at 56°C. The mixture “serum-RDE” was cooled in a time range from 30 min to 4h at 4°C. The "serum-RDE" mixture was then absorbed on 10% tRBCs in PBS for 30 min, at room temperature (about 20-25°C), and then centrifuged at 5°C for 10 min at 700 g. RDE-treated sera of 1:10 starting dilution were serially diluted and an equal volume of each influenza virus (50 μL), adjusted to a concentration of 4 hemagglutination units (HAU)/50 μL, was added to each well. Then, 50 µL of 0.5 % turkey erythrocytes (ALBA, SANOFI, France) diluted in PBS were added for 1h. Then, inhibition of hemagglutination or hemagglutination was visually read after 1h at room temperature. The HI titer was determined by the reciprocal dilution of the last well that contained non-agglutinated RBCs. A value of 5 corresponding to half of the initial dilution (1:10) was arbitrary given to all sera determined negative to standardize and perform the statistical analysis. Statistical analysis [1336] All HI titers were log10 transformed prior to statistical analyses. To compare the groups and determine the adjuvant effect of SPA09, an ANOVA (Analysis of Variance) model with mRNA as fixed factor was applied. For the comparison between the different formulations (LNP/mRNA at different doses of mRNA, LNP/mRNA at different doses of mRNA + different doses of SPA09), a Tukey’s adjustment for multiple comparison was performed. The model’s residuals were studied to test the model’s validity (normality, extreme individuals…). Statistical analyses were performed on groups with more than 50% of responders. All analyses were done on SAS v9.4®. A margin of error of 5% was used for effects of the main factors. Example 4: The addition of a 200 µg-dose of SPA09 to LNP/mRNA at a 0.1µg dose of mRNA allows to induce similar immunogenicity as a 2µg dose of mRNA without SPA09, without increasing reactogenicity [1337] The objective of this study was to determine the adjuvant effect of a PAA polymer such as SPA09 on immunogenicity (as assessed by HI antibody titers), as well as reactogenicity (as assessed by monitoring of clinical signs) in mice, induced by a low dose of mRNA, in comparison with a 20x higher dose of mRNA without SPA09. [1338] Mice were immunized as described in Example 3, with two i.m. injections (as described in Figure 2) of a 0.1µg-dose of mRNA with a coding sequence of SEQ ID NO: 3, encoding HA from A/Tasmania/503/2020 (H3N2) Flu strain (HA-H3 Tasm) encapsulated in an LNP with OF-02 as the ionizable lipid, alone or with a 200 µg dose of SPA09. As a comparative group, mice were immunized with a 2 µg dose of the same mRNA in the same LNP without SPA09, using the same immunization schedule. Mice immunized with PBS only were used as a negative control group. [1339] HI antibody titers were measured in mouse sera at d42, 3 weeks following the second i.m. administration, using live A/Tasmania/503/2020 (H3N2) Flu virus, as described in Example 3. [1340] As shown in Figure 3A, the 0.1µg dose of mRNA induced HI titers significantly lower than those induced by 2µg-dose of the same formulation (p-value<0.001), with approximately 10-fold decrease in HI titers (247 vs 2207). The addition of SPA09 at 200µg- dose significantly increased HI titers induced by the low dose of 0.1µg of mRNA (p- value=0.002) with approximately 5-fold increase of HI titers (1312 vs 247). No significant difference was measured between HI titers induced by the 2µg-dose of mRNA and those induced by the 0.1µg-dose of mRNA with 200µg-dose of SPA09, showing that SPA09 was able to restore HI titers induced by the high dose of mRNA. The inventors also tested in similar conditions some other known adjuvants, such as a squalene-based oil-in-water emulsion adjuvant. The addition of any of these other adjuvants did not allow to increase, and even decreased, the HI titers induced by the low dose of 0.1µg of mRNA (data not shown). [1341] As shown in Figure 3B, no clinical signs were observed in mice after each injection of a 0.1µg-dose of mRNA, whereas 80% to 100% of mice which received two injections of 2µg-dose of mRNA displayed swelling, piloerection, and unsteady state the day following each injection. Then, only swelling at the site of injection was observed until complete disappearance 6 to 7 days following the first and the second injection. The addition of 200µg- dose of SPA09 with 0.1µg- dose of mRNA induced comparable magnitude of the clinical signs (or potentially, slightly fewer clinical signs) compared to those measured with the high dose of 2µg-dose of mRNA. Example 5: The addition of SPA09 at a dose as low as 50µg, to LNP/mRNA at a 0.1µg dose of mRNA allows to increase immunogenicity, with only a very limited increase in reactogenicity [1342] The objective of this study was to assess the adjuvant effect of three different doses of SPA09, using a different LNP, on immunogenicity and reactogenicity in mice. [1343] Mice were immunized as described in Example 3, with two i.m. injections (as described in Figure 2) of a 0.1µg-dose of mRNA with a coding sequence of SEQ ID NO: 3, encoding HA-H3 Tasm, encapsulated in an LNP with GL-HEPES-E3-E12-DS-4-E10 as the ionizable lipid, alone or with a 50µg-, 100µg- or 200µg-dose of SPA09. [1344] HI antibody titers were measured in mouse sera at d35, 2 weeks following the second i.m. administration, using live A/Tasmania/503/2020 (H3N2) Flu virus, as described in Example 3. [1345] As shown in Figure 4A, all doses of SPA09 significantly increased the HI titers of a 0.1µg- dose of mRNA. Indeed, the HI titers measured with the unadjuvanted 0.1µg- dose of mRNA (Geometric Mean Titer / GMT value of 22) were from 7.5-fold to 16-fold lower than the ones measured in adjuvanted groups. Moreover, 0.1µg-dose of mRNA with the lowest dose of SPA09 (50µg) tended to induce higher HI titers (GMT value of 359) compared to 100µg- and 200µg SPA09 per dose (GMT values of 165 and 207, respectively). [1346] As shown in Figure 4B, no clinical signs were observed in mice after each injection of a 0.1µg-dose of mRNA, either alone or with a 50µg dose of SPA09. The addition of 100µg or 200µg-dose of SPA09 to 0.1µg-dose of mRNA induced slightly higher but transitory clinical signs, which were not adverse clinical signs (mainly swelling at the site of injection which appeared the day following i.m. administration and was no more detectable after 3 days post-injection). [1347] Overall, all tested doses of SPA09 increased of a 0.1 µg dose of mRNA, but the lowest dose of SPA09 (50µg-dose) induced the highest HI titers, without increasing reactogenicity (clinical signs). Example 6: The addition of SPA09 at a dose as low as 50µg, to LNP/mRNA at a 0.4µg dose of mRNA allows to increase immunogenicity, without increasing reactogenicity [1348] In this example, a similar study as in Example 5 was carried out, but with a higher dose of mRNA (0.4µg). [1349] Mice were immunized as described in Example 3, with two i.m. injections (as described in Figure 2) of a 0.4µg-dose of mRNA with a coding sequence of SEQ ID NO: 3, encoding HA-H3 Tasm, encapsulated in an LNP with GL-HEPES-E3-E12-DS-4-E10 as the ionizable lipid, alone or with a 50µg-, 100µg- or 200µg-dose of SPA09. [1350] HI antibody titers were measured in mouse sera at d35, 2 weeks following the second i.m. administration, using live A/Tasmania/503/2020 (H3N2) Flu virus, as described in Example 3. [1351] As shown in Figure 5A, all doses of SPA09 significantly increased the HI titers of a 0.4µg- dose of mRNA. Indeed, the HI titers measured with the unadjuvanted 0.4µg- dose of mRNA (GMT value of 62) were from 6.3-fold to 24-fold lower than the ones measured in adjuvanted groups. Moreover, 0.4µg-dose of mRNA with the lowest dose of SPA09 (50µg) induced higher HI titers (GMT value of 1518) compared to 100µg- and 200µg SPA09 per dose (GMT values of 439 and 391, respectively). [1352] As shown in Figure 5B, no clinical signs were observed in mice after each injection of a 0.4µg-dose of mRNA. Slight clinical signs (mainly transient swelling) were observed at the site of injection with 0.4µg-dose of mRNA plus 50µg-dose of SPA09. The swelling was no more detectable 3 days following the second administration. The addition of 100µg or even more particularly 200µg-dose of SPA09 to 0.4µg-dose of mRNA induced higher clinical signs, compared to the 50µg-dose of SPA09. [1353] Overall, all tested doses of SPA09 increased the HI titers of a 0.4 µg dose of mRNA, but the lowest dose of SPA09 (50µg-dose) induced the highest HI titers (with a x24- fold increase, compared to the unadjuvanted group), with only a very limited increase of reactogenicity. Example 7: The use of 50µg-dose of SPA09 allowed to achieve a dose-sparing of mRNA of 16, without increasing reactogenicity in vivo. [1354] The aim of this study was to determine the dose-sparing which can be achieved with the use of a PAA polymer such as SPA09, by comparing immunogenicity (HI titers) and reactogenicity in mice induced by lower doses (0.1µg or 0.4µg) of mRNA plus 50µg-dose of SPA09 versus a higher, reference dose (1.6µg) of mRNA. The dose of 1.6 µg of mRNA was considered as the reference dose under our experimental conditions, i.e. the lowest dose below which a significant dose effect on HI titers was no longer measurable. [1355] Mice were immunized as described in Example 3, with two i.m. injections (as described in Figure 2) of mRNA with a coding sequence of SEQ ID NO: 3, encoding HA-H3 Tasm, at a dose of 0.1µg or 0.4µg (alone or with 50µg-dose of SPA09) or at a reference dose of 1.6µg, encapsulated in an LNP with GL-HEPES-E3-E12-DS-4-E10 as the ionizable lipid. [1356] HI antibody titers were measured in mouse sera at d35, 2 weeks following the second i.m. administration, using live A/Tasmania/503/2020 (H3N2) Flu virus, as described in Example 3. [1357] As shown in Figure 6A and 6B, the addition of SPA09 at 50µg-dose significantly increased HI titers induced by the doses of 0.1µg and 0.4 µg of mRNA, with a significant 16- fold increase (GMT 22 vs. 359) and 24-fold increase (GMT 62 vs 1518), respectively. No significant difference was measured between HI titers induced by the 1.6µg-dose of mRNA (reference dose) and those induced by the 0.1µg-dose of mRNA with 50µg-dose of SPA09. Moreover, HI titers measured with 0.4µg- dose of mRNA with 50µg SPA09 were 3-fold higher than those measured with the reference dose of 1.6µg mRNA, suggesting that a 4-fold lower dose of mRNA with 50µg SPA09 can induce higher HI titers than the unadjuvanted reference dose. These results demonstrated that a dose-sparing of 16 could be achieved with SPA09. [1358] As shown in Figure 6C, no clinical signs were observed in mice after each injection of a 0.1µg- or a 0.4µg-dose of mRNA. Swelling at the site of injection was measured in 50% of mice injected with the refence dose of 1.6µg mRNA, only for one day following the second administration. No clinical signs were observed in mice after each injection of 0.1µg- dose of mRNA with 50µg of SPA09. Only swelling was observed at the site of injection with 0.4µg-dose of mRNA with 50µg-dose of SPA09 – this occurred only for 3 days after the second administration, and was no more detectable thereafter. [1359] Overall, the use of 50µg-dose of SPA09 allowed to achieve a dose-sparing of mRNA of 16, without increasing reactogenicity in vivo. Example 8: The addition of SPA09 to LNP/mRNA does not induce an increase in antigen expression [1360] The aim of this study was to investigate on the mode of action of SPA09, and in particular to determine if the improvement of HI titers and dose-sparing effect achieved with the use of SPA09 was linked to an increase in antigen expression. To this aim, in vivo and ex vivo bioimaging using mRNA encoding Firefly Luciferase (FFLuc) was carried out. FFLuc is a reporter bioluminescent protein classically used to monitor by bioimaging the kinetics of antigen expression in vivo or ex vivo, at different time points. [1361] Design of mouse studies for in vivo and ex vivo bioimaging is shown in Figure 7. [1362] Briefly, eight-week-old female Balb/c mice were anesthetized with 2% isoflurane in oxygen (Alcyon, France; Ref.1818290) and injected into the right quadriceps with 0.4 µg of mRNA with a coding sequence of SEQ ID NO: 4 encoding FFLuc, encapsulated in an LNP with GL-HEPES-E3-E12-DS-4-E10 as the ionizable lipid, alone or with 50µg of SPA09, under a final volume of 30 µL in PBS 1X. One group of four mice injected with mRNA with a coding sequence of SEQ ID NO: 3, encoding HA-H3 Tasm, encapsulated in the same LNP, was used as negative control. [1363] Bioimaging acquisitions were performed using IVIS^® Spectrum CT imaging system (Perkin Elmer). The level of FFLuc in vivo expression was assessed by bioluminescence imaging at 6 hours,1 day, 2 days, 3 days and 7 days post-injection in the right quadriceps from the same five mice per group, injected intraperitoneally (i.p.) with 150 mg/kg of D-luciferin (Invitrogen) before acquisition. Then, mice were imaged 15 min post-i.p. injection. Five mice per group were euthanized after deep anesthesia by cervical elongation at 6 hours, 3 days and 7 days post-injection and right quadriceps were sampled and analyzed under the camera bioluminescence signal acquisition. All data were analyzed using the LIVING IMAGE^® software provided by PERKIN ELMER and the quantification performed over a region of interest (ROI) applied to the injected area. The bioluminescence signal was expressed as total radiance (photon/s) of the ROI. [1364] As shown in Figure 8, the addition of 50µg-dose of SPA09 did not increase FFLuc expression in vivo or ex vivo, at all timepoints. These results demonstrate that the ability of SPA09 to improve specific immune response (HI titers) does not appear to be linked to an increase in antigen expression. Example 9: The addition of SPA09 to LNP/mRNA induces an adjuvant effect [1365] The aim of this study was to investigate on the mode of action of SPA09, and in particular to determine if the improvement of HI titers and dose-sparing effect achieved with the use of SPA09 was linked to an adjuvant effect. To this aim, analysis of early cytokines and chemokines profile responses was carried out. Indeed, an adjuvant molecule is known to activate innate immune cells which produce cytokines and chemokines, which improves immune cell recruitment and activation at the site of administration. The activation of innate immune system enhances the magnitude and the durability of the specific and functional immune responses to vaccines. [1366] Design of mouse studies for analysis of proinflammatory cytokines and chemokines profile responses is shown in Figure 9. [1367] Briefly, fifteen BALBc/ByJ mice per group and per dose, aged 7–8 weeks (body weight 18–20 g) at the time of first immunization were obtained from CHARLES RIVER LABORATORIES (Saint Germain sur l’Arbresle, France). Mice received two injections (50µL), given three weeks apart (d0 and d21) by slow intramuscular (i.m.) administration with a 0.1µg- dose of mRNA with a coding sequence of SEQ ID NO: 3, encoding HA-H3 Tasm, encapsulated in an LNP with GL-HEPES-E3-E12-DS-4-E10 as the ionizable lipid, alone or with SPA09 (at a dose of 20µg or 50µg), or with 1.6 µg of the same mRNA in the same LNP, alone. Intramuscular (i.m) injection was done in the quadriceps muscle region, after shaving of the injected zone and under isoflurane anesthesia. As negative control group, five mice received two injections with PBS buffer, 3 weeks apart. As positive control group, eight mice received 4.5 µg of monovalent Flu vaccine A/Tasmania/503/2020 (H3N2) strain derived from VAXIGRIP™, according to the same immunization schedule. Blood sampling and serum preparation [1368] Intermediate blood samples were collected four days before the first i.m. administration (d-4) by puncture in the submandibular vein from all mice under isoflurane 4% anesthesia to determine the baseline of serum cytokine/chemokine concentrations in each mouse. Approximately 200 µL of blood per mouse were collected in vials containing clot activator and serum separator (BD MICROTAINER SST Tubes, ref 365968). After 1 hour at +5°C±3°C, blood samples were centrifuged at 12000rpm for 90 seconds and sera were stored at -80°C until multiplex array analysis. [1369] Then, blood samples from five mice per group per time point were collected on 4 hours, one day and 3 days after the second i.m. administration at d21, under deep anesthesia with ROMPUN/IMALGEN 500 by exsanguination. The mixture IMALGENE (1.6 mg of Ketamine) and ROMPUN (0.32 mg of Xylazine) was administrated by intraperitoneal route under a volume of 200 µL before blood sampling. Maximum of blood per mouse was collected in vials containing clot activator and serum separator (BD VACUTAINER SST II Advance ref 367957). After at least 1 hour at +5°C±3°C, the blood was centrifuged at 1600 g for 20 minutes and sera were stored at -80°C until cytokine/chemokine multiplex array analysis. Muscle sampling and preparation [1370] In parallel of blood sampling, the right quadriceps (site of injection) from five mice per group per time point were collected on 4 hours, one day and 3 days after the second i.m. administration at d21, under deep anesthesia with a mixture of ROMPUN/IMALGEN injected intraperitoneally and euthanasia by cervical elongation. [1371] Each quadriceps was collected in PRECELLYS vials (ref CK25 or CK25R) containing 500µL of PBS 1X plus SIGMAFAST Protease inhibitor (Ref S8820-20TAB lot SLCG7266 Sigma). To determine each muscle weight, vials were weighted before and after muscle addition to report cytokine and chemokine quantity per g of muscle (pg cytokines/g de muscle). Then, quadriceps were stored at -80°C until cool homogenization with PRECELLYS (CRYOLYS EVOLUTION) apparatus. One day before muscle crushing, vials containing mouse quadriceps in PBS 1X plus protease inhibitor were thawed at 4°C. Quadriceps were crushed using appropriate PRECELLYS program in ice. Vials were centrifuged at 8000g for 2 minutes at 5°C and approximately 500µL of supernatant were transferred in Spin-X centrifuge tubes (Costar, Ref 8160) and filtered on 0.22µm for 2 min at 8000g. [1372] 50µL of filtered quadriceps supernatant were then distributed in V-shaped bottom 96-well plates (FALCON ref 353077) and stored at -80°C until cytokine/chemokine multiplex array analysis. Proinflammatory cytokine and chemokines assay (multiplex array analysis) [1373] Concentration of sixteen cytokines and chemokines (G-CSF, GM-CSF, GRO alpha (CXCL1), IFN alpha, IFN gamma, IL-1 beta, IL-10, IL-27, IL-6, IP-10 (CXCL10), MCP-1 (CCL2), MIP-1 alpha (CCL3), MIP-1 beta (CCL4), MIP-2 alpha (CXCL2), RANTES (CCL5) and TNF alpha) were determined in mouse serum samples collected 4 days prior immunization, 4 hours, one day and 3 days following the second injection and in filtered supernatant of crushed quadriceps collected 4 hours, one day and 3 days following the second injection, by using a Mouse PROCARTA Plex 16-Plex kit (THERMOFISHER, ref PPX-16-MXFVM2G) and according to kit instructions. IL-1RA concentration was determined in mouse serum and filtered supernatant from mouse quadriceps, collected at the same time points, by using an ELISA IL- 1RA R&D System kit (Ref #MRA00) and according to provider instructions. [1374] Amounts of cytokines and chemokines were expressed in pg/mL in mouse serum and in pg/g muscle in quadriceps supernatant for each individual mouse. Statistical analysis [1375] All concentrations were log10 transformed prior to statistical analyses. The values obtained were analyzed using a mixed model with group and time as fixed factor and their interaction. The model’s residuals were studied to test the model’s validity (normality, extreme individuals, etc.). Statistical analyses were performed on groups with more than 50% of responders and all groups with no variability were discarded from the analysis (ex: PBS group). All analyses were done on SAS VIYA®. A margin of error of 5% was used for effects of the main factors and 10% for the interaction. Results [1376] As shown in Figure 10A-G, the addition of SPA09 significantly improved the production in the muscle of proinflammatory cytokines and chemokines involved in immune cell recruitment, such as G-CSF, GM-CSF, TNF-α, RANTES, MIP-1α, at 4 hours and/or 1 day following the second i.m. administration, compared to the unadjuvanted 0.1µg-dose of mRNA, up to concentrations which were similar or higher than those induced by the reference dose of 1.6µg of mRNA. Similarly, the addition of SPA09 significantly improved the production in the muscle of MIP-1-β, MIP-2α and MCP-1, at 1 day and/or 3 days following the second i.m. administration compared to the unadjuvanted 0.1µg-dose of mRNA, up to concentrations which were similar or higher than those induced by the reference dose of 1.6µg of mRNA. [1377] The addition of SPA09 at either of the tested doses significantly improved the production of IFN-γ from 4 hours to 3 days following the second i.m. administration, compared to the unadjuvanted 0.1µg-dose of mRNA. It should more particularly be noted that the adjuvanted 0.1µg-dose of mRNA induced significantly higher IFN-γ production in muscle than the unadjuvanted reference dose of 1.6µg, mainly 4hours and 1 day following the second i.m. administration (Figure 10F). This increase in IFN-γ expression is the signature of a Th1-skewed immune response. This cytokine interacts with many immune cells, leading to an improvement of the quality of the humoral and cellular immune response. [1378] Similarly, the addition of SPA09 significantly improved the production of IP-10 (IFN-γ-inducible protein 10), also called CXCL10, from one day to 3 days following the second i.m. administration compared to the unadjuvanted 0.1µg-dose of mRNA (Figure 10G). IP-10 is secreted by several cell types in response to IFN-γ and plays a role in chemoattracting monocytes/macrophages, T cells, NK cells, and dendritic cells at the site of injection and promoting T cell adhesion to endothelial cells. It should be noted that the adjuvanted 0.1µg- dose of mRNA induced significantly higher IP-10 production in muscle than the unadjuvanted reference dose of 1.6µg, mainly 3 days following the second i.m. administration. [1379] Similar results were obtained in serum samples, especially with cytokines IFN- γ and IP-10. The profile of proinflammatory cytokines and chemokines expression in the serum was similar to the profile at the site of injection (muscle), with merely a difference in magnitude. These results demonstrate that a systemic response was also obtained. [1380] Overall, these results show that the ability of SPA09 to improve potency (HI titers) appears to be linked to an adjuvant effect. Example 10 : The addition of SPA09 to a LNP co-encapsulating two different mRNAs encoding RSV and hMPV pre-fusion (pre-F) antigens, respectively, allows to significantly increase immunogenicity, without significantly increasing reactogenicity [1381] The objective of this study was to use a PAA polymer such as SPA09 with a LNP co-encapsulating two different mRNAs, encoding RSV and hMPV pre-fusion (pre-F) antigens, respectively (comprising a coding sequence of SEQ ID NO:7 and SEQ ID NO: 8, respectively), in a 1:1 ratio, and to assess the effect on immunogenicity and reactogenicity. [1382] Briefly, eight mice per group received two i.m. injections, three weeks apart, on day 0 (d0) and d21, with the appropriate doses of mRNAs (0.2µg, 1 µg or 5 µg in total) co- encapsulated in an LNP with GL-HEPES-E3-E12-DS-4-E10 as the ionizable lipid, alone or co- administered with 10µg, 25µg or 50µg of SPA09. As a negative control group, eight mice received two i.m. injections three weeks apart, with SPA09 only (50 µg). [1383] The effect on immunogenicity was assessed at d0 (pooled samples) and at d35 (individual samples) by RSV and hMPV microneutralization assay (MNA). [1384] Briefly, the MNA titer was measured as follows: Vero cells (ATCC CCL-81) were seeded at 30,000 cells/well in 96-well plates suitable for fluorescence reading one day prior to infection. Serum samples were heat inactivated and 4-fold serially diluted from 1:20 to 1:81,920. Diluted sera were combined 1:1 with RSV strain A2 or hMPV strain A2 expressing Green Florescent Protein reporter and incubated for 1 hour. The serum-virus mixtures were added to the cell plates which were incubated for 24 hours. The plates were then read on a high content imager and the fluorescent events were quantified. Serum 50% neutralizing titers were calculated using 4-parameter logistics regression in SoftMax GxP. [1385] Statistical analyses between groups were performed in Prism using the one- way ANOVA on Log2 transformed data. [1386] Results of MNA titers at d35 are shown in Figure 11A. [1387] For RSV (Figure 11A, top), at the 0.2µg dose of mRNAs, there was a significant increase in titers with increasing amounts of SPA09. The addition of 25µg or 50µg of SPA09 to the 0.2µg dose of mRNAs induced RSV titers significantly higher than those induced with the 0.2µg dose of mRNAs without SPA09, and not significantly different from those induced by a 5-fold higher dose of mRNAs (1µg) without SPA09. On the other hand, the 1µg dose of mRNAs without SPA09 induced RSV titers not significantly different from those induced with the 5µg dose of mRNAs without SPA09, thus showing approaching saturating RSV titers already at the 1µg dose of mRNAs. [1388] For hMPV (Figure 11A, bottom), at the 0.2µg dose of mRNAs, there was a gradual, but not significant, increase in titers with increasing amounts of SPA09. At the 1µg dose of mRNAs, there was a significant increase in hMPV titers with increasing amounts of SPA09. The use of as little as 10µg of SPA09 with this 1µg dose of mRNAs could increase hMPV titers to a level comparable to those induced by a 5-fold higher dose of mRNAs (5µg) without SPA09. The use of 50µg of SPA09 reduced the difference even further. [1389] The effect on reactogenicity was assessed by monitoring edema at injection site for 3 days after each immunization. Reactogenicity results were based on the edema severity score which is a measurement of the degree of swelling at the injection site from 0 (none observed) to 5 (severe) and are shown on Figure 11B. The reactogenicity for all groups was mild, with a mean edema score between 0 and 0.5 at d24 (3 days after the second immunization) for all groups. [1390] Overall, these data show that SPA09 is able to increase titers for both RSV and hMPV in a dose-dependent manner, without significantly increasing reactogenicity. When the dose of mRNAs is appropriately selected, the use of SPA09 could allow to use up to 5-fold lower dose of mRNAs, while inducing similar immunogenicity levels. Example 11: Safety and Immunogenicity after a single injection of different dose formulations of an RSV/hMPV mRNA vaccine candidate encapsulated in an LNP and administered with or without the adjuvant SPA09. [1391] The objective of the study is to evaluate the safety and immune response in humans of an mRNA vaccine candidate for the prevention of disease caused by the respiratory syncytial virus (RSV) and the human metapneumovirus (hMPV), with different amounts of the adjuvant SPA09. [1392] The vaccine candidate is an mRNA LNP-based vaccine comprising mRNAs encoding RSV and hMPV pre-fusion (pre-F) antigens, with coding sequences corresponding to SEQ ID NO:7 and SEQ ID NO:8 respectively, wherein both coding sequences are flanked in 5’ by the 5’UTR of SEQ ID NO: 1 and in 3’ by the 3’UTR of SEQ ID NO: 2. The mRNAs are co-encapsulated in a LNP with GL-HEPES-E3-E12-DS-4-E10 as the ionizable lipid, alone or co-administered with different doses of SPA09. [1393] This clinical study is more specifically a Phase 1, dose-escalation, randomized, modified double-blinded, parallel-group, multi-arm study. This translational study is conducted to investigate the safety and immunogenicity of different doses of the mRNA (RSV/hMPV) vaccine candidate in combination with the SPA09 adjuvant, in adult participants aged 60 to 75 years. [1394] It utilizes a 1:3 ratio of RSV:hMPV mRNAs. Three mRNA dose combinations mixed with the adjuvant SPA09 are evaluated and compared to the same mRNA dose combinations without adjuvant. [1395] In this study, 3 doses levels of SPA09 are tested: 125 µg, 250 µg, and 500 µg. [1396] The immunogenicity objective is to assess the immunogenicity of the different formulations of the adjuvanted and non-adjuvanted RSV/hMPV vaccine candidates, wherein the adjuvant is SPA09, and to assess the kinetics and durability of the immune response against RSV and hMPV after vaccination up to 6 months. [1397] This study is conducted with a monovalent RSV vaccine as control and active comparator. [1398] The study details include: • Each participant remains in the study for approximately 6 months • Vaccines tested in this study: o Vaccine with different amounts of adjuvant (mRNA [RSV/hMPV] + SPA09 adjuvant) or, o Vaccine without adjuvant (mRNA [RSV/hMPV]) or, o Monovalent RSV vaccine, used a control and active comparator • The study vaccine is administered as a single intramuscular (IM) injection in the arm muscle. Number of Participants: [1399] A total of approximately 390 participants is randomized for this study. Study Arms and Duration: [1400] Eligible participants are randomized to receive a single IM injection at D01 of: - either one of the three doses (dose 1, dose 2 and dose 3) of mRNAs (RSV/hMPV) in the mRNA/LNP vaccine, with SPA09 adjuvant at 125µg, 250 µg or 500 µg; - either one of the three doses (dose 1, dose 2 and dose 3) of mRNAs (RSV/hMPV) in the mRNA/LNP vaccine, without SPA09 adjuvant, or - a dose of the monovalent RSV vaccine. [1401] The duration of each participation is approximately 6 months for each participant. Design of the study [1402] Blood samples are collected for each participant within 14 days before the IM injection, and at days D01, D02, D04, D08, D29, D91 and D181, wherein the IM injection is made at D01. [1403] The solicited injection site, systemic reactions and out-of-range biological results, occurring through 7 days after vaccination, are collected between D01 and D08. [1404] The unsolicited Adverse events are collected between D01 and D29. [1405] All serious adverse events and adverse events of special interest are collected throughout the study (i.e., through 6 months after vaccination). [1406] RSV serum neutralizing antibody titers are assessed at pre-vaccination (D01) and 28 days (D29), 3 months (D91), and 6 months (D181) post-vaccination, in all participants. [1407] hMPV serum neutralizing antibody titers are assessed at pre-vaccination (D01) and 28 days (D29), 3 months (D91), and 6 months (D181) post-vaccination, in all participants, except in those receiving the monovalent RSV vaccine. [1408] RSV serum anti-F immunoglobulin G antibody (Ab) titers are assessed at pre- vaccination (D01), 28 days (D29), 3 months (D91), and 6 months (D181) post-vaccination in all participants. [1409] hMPV serum anti-F immunoglobulin G antibody (Ab) titers are assessed at pre- vaccination (D01), 28 days (D29), 3 months (D91), and 6 months (D181) post-vaccination in all participants, except in those receiving the monovalent RSV vaccine. Results of the study [1410] Preliminary results indicate that no safety signal was detected in any group, with an acceptable safety profile in particular in groups having received the mRNA/LNP vaccine, without or with SPA09 adjuvant, at all doses. Example 12: The addition of other polyacrylic acid polymers induces similar adjuvanting/dose-sparing effect as the addition of SPA09 [1411] In this example, a similar study as in Example 6 was carried out, with the same dose of mRNA (0.4µg), but with polyacrylic acid (PAA) polymers having different weight average molecular weights. [1412] Briefly, mice were immunized as described in Example 3, with two i.m. injections (as described in Figure 2) of a 0.4µg-dose of mRNA with a coding sequence of SEQ ID NO: 3, encoding HA-H3 Tasm, encapsulated in an LNP with GL-HEPES-E3-E1-DS-4-E10 as the ionizable lipid, alone or with a 20µg-dose of either SPA09 or of polyacrylic acid (PAA) polymer having a weight average molecular weight (Mw) of 100 kDa (PAA 100 kDa). As negative control, mice were injected PBS (buffer). [1413] HI antibody titers were measured in mouse sera at d35, 2 weeks following the second i.m. administration, using live A/Tasmania/503/2020 (H3N2) Flu virus, as described in Example 3. [1414] As shown in Figure 12, both types of PAA, namely SPA09 and PAA 100 kDa, significantly increased the HI titers of a 0.4µg- dose of mRNA. Indeed, the HI titers measured in both adjuvanted groups were significantly higher than the ones measured with the unadjuvanted 0.4µg- dose of mRNA. [1415] Overall, tested PAA having Mw ranging from 100 kDa to 600 kDa all increased the HI titers of a 0.4 µg dose of mRNA. Example 13: SPA09 induces adjuvanting/dose-sparing effect when different types of LNPs are used. [1416] The aim of this study was to confirm that the dose-sparing effect which is achieved with the use of a PAA polymer such as SPA09, can be achieved with the use of different LNPs, comprising different ionizable lipids, by comparing immunogenicity (HI titers) in mice induced by 0.1µg or 0.4µg doses of mRNA, encapsulated in an LNP with ALC-0315, SM-102 or MC3 as the ionizable lipid, alone or with a 20µg-dose of SPA09. [1417] Mice were immunized as described in Example 3, with two i.m. injections (as described in Figure 2) of mRNA with a coding sequence of SEQ ID NO: 3, encoding HA-H3 Tasm, at a dose of 0.1µg or 0.4µg, encapsulated in an LNP with ALC-0315, SM-102 or MC3 as the ionizable lipid, alone or with 20µg-dose of SPA09. In this example, the LNPs with MC3, SM-102 or ALC-0315 as the ionizable lipid had a different composition, compared to the LNPs described in Example 1. The LNPs with MC3 or SM-102 as the ionizable lipid contained ionizable lipid [MC3 or SM-102] / DSPC / cholesterol / DMG-PEG, at the molar ratio of 50:10:38.5:1.5. The LNP with ALC-0315 as the ionizable lipid contained ALC-0315 / DSPC / cholesterol / ALC-0159, at the molar ratio of 47.5:10:40.7:1.8. [1418] A control with 0.4µg mRNA encapsulated in an LNP with GL-HEPES-E3-E12- DS-4-E10 as the ionizable lipid, without SPA09, as described in Example 1, was also used. As negative control, mice were injected with the dilution buffer. [1419] HI antibody titers were measured in mouse sera at d35, 2 weeks following the second i.m. administration, using live A/Tasmania/503/2020 (H3N2) Flu virus, as described in Example 3. [1420] As shown in Figure 13, the addition of SPA09 at 20µg-dose significantly increased HI titers induced by the doses of 0.1µg and 0.4 µg of mRNA, for the different LNPs tested. [1421] No clinical sign was detected at the site of injection, for all mice. [1422] These results demonstrate that a dose-sparing effect could be achieved with a PAA polymer such as SPA09, irrespective of the LNP used for the encapsulation of the mRNA, and in particular irrespective of the ionizable lipid contained in the LNP. Example 14: CD4+ T-cell response, observed by Intracellular Cytokine Staining (ICS). [1423] In this study, the level of CD4+ T cells specific to the antigen secreting IFNγ, IL- 2 and/or TNF-α was monitored, including the percentage of mono- or polyfunctional-secreting CD4⁺ T cells specific to the antigen. [1424] Mice were immunized as described in Example 3, with two i.m. injections (as described in Figure 2) of a 0.1µg-dose of mRNA with a coding sequence of SEQ ID NO: 3, encoding HA-H3 Tasm, encapsulated in an LNP with GL-HEPES-E3-E1-DS-4-E10 as the ionizable lipid, alone or with a 20µg-dose or 50µg-dose of SPA09, or with 1.6 µg of the same mRNA in the same LNP, alone. As negative control group, mice received two injections with buffer, 3 weeks apart. As positive control group, mice received 10µg of recombinant HA with 50µg/dose of SPA09, according to the same immunization schedule. [1425] The Intracellular Cytokine Staining (ICS) assay was used to assess specific T cell responses to HA in spleen or in lymph nodes draining the site of injection from immunized or infected mice. [1426] Briefly, mouse spleens were collected two weeks following the second intramuscular administration (d35) in sterile RPMI culture medium and were mechanically disrupted through a 70μm cell strainer (Falcon # 352350) to obtain a single cell suspension followed by red blood cells lysing with Red Blood Cell Lysing Buffer (Sigma # R7757).1.10⁶ splenocytes/well were cultured in 96-well flat bottom plates in duplicates and stimulated for 1h at 37°C in RPMI-1640 supplemented with L-Glutamine, ^-mercaptoethanol, Penicilline/Streptomycine (Gibco # 42401-018, 25030-024, 31350-010, 15140-122) and 10% heat inactivated Fetal Bovine Serum (HI FBS, Hyclone # SH30084.4), and with 1µg/mL CMH- I or CMH-II specific pools of HA-Tasmania peptides, or 1µg/mL Phorbol 12-myristate 13- acétate + 50ng/mL Ionomycine (Sigma # P1585 and I0634) as positive control, or medium alone for background determination. After 1h incubation, 10µg/mL Brefeldin A (Sigma #B7651- 5MG) was added to each well. Plates were incubated for 5 additional hours at 37°C. [1427] Cells were harvested and washed twice with PBS before incubation for 15 minutes at room temperature with Zombie NIR (Biolegend # 423106) for cell viability staining. Cells were washed twice with staining buffer (PBS + 0.5% BSA) before being incubated with TruStain FcX Plus and Monocyte Blocker (Biolegend # 156604 and 426103) for 5 min at +4°C as per the manufacturer’s protocol. Cell surface markers were stained for 20 minutes at 4°C using the following combinations of antibodies diluted in staining buffer: CD14 APC/Fire750, CD19 APC/Fire750, CD3 AF700, CD4 Kiravia Blue520, and CD8 BV510 (Biolegend #123332, 115558, 100216, 100478, and 100752). Cells were washed twice with staining buffer before being permeabilized using the Cytofix/Cytoperm Fixation/Permeabilization Solution Kit (BD Biosciences #554714) used as per the manufacturer’s protocol. Intracellular markers were stained for 30 minutes at +4°C using the following combinations of antibodies diluted in PermWash buffer: IFN-^ BV421, TNF-^ BV711, IL-2 APC and IL-5 PE (Biolegend # 505830, 506349, 503810 and 504304). Cells were washed twice with PermWash Buffer and twice with staining Buffer before being acquired on an Aurora Flow cytometer (Cytek) and analyzed with FlowJo Software (Becton Dickinson). [1428] All frequencies of cytokine-secreting T cells specific to HA were log10 transformed prior to statistical analyses. As in Example 3, to compare the groups and determine the adjuvant effect of SPA09, an ANOVA (Analysis of Variance) model with mRNA as fixed factor was applied. For the comparison between the different formulations (LNP/mRNA at different doses of mRNA, LNP/mRNA at different doses of mRNA + different doses of SPA09), a Tukey’s adjustment for multiple comparison was performed. The model’s residuals were studied to test the model’s validity (normality, extreme individuals…). Statistical analyses were performed on groups with more than 50% of responders. All analyses were done on SAS v9.4®. A margin of error of 5% was used for effects of the main factors. [1429] As shown in Figure 14A, the addition of 20µg SPA09 to mRNA encoding HA- H3 Tasm antigen encapsulated in LNP increased single IFN-γ and TNF-α-secreting CD4⁺ T cells specific to HA-H3 Tasm, demonstrating a Th-1 skewed profile. mRNA encoding HA-H3 antigen encapsulated in LNP, and adjuvanted with SPA09 was more prone to induce a Th-1 profile than recombinant protein HA antigen (rHA) adjuvanted with SPA09. [1430] Moreover, as shown in Figure 14B, the addition of 20µg SPA09 to mRNA encoding HA-H3 Tasm antigen encapsulated in LNP increased polyfunctional-secreting CD4⁺ T cells specific to HA-H3 Tasm, described in the literature as predictive of good quality of immune response.

Claims

[CLAIMS] 1. Immunogenic composition comprising: - at least one water-soluble polyanionic polymer, - at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, and - at least one nucleic acid encoding at least one antigen.

2. The immunogenic composition according to claim 1, wherein the water-soluble polyanionic polymer is selected from a group consisting of polyacrylic acid polymer, polymethacrylic acid polymer, hyaluronic acid polymer, polyglutamic acid polymer, polyaspartic acid polymer, polystyrenesulfonic acid polymer, heparin polymer, dextran sulfate polymer, carboxymethylcellulose polymer, alginic acid polymer, combinations thereof, and pharmaceutically acceptable salts thereof.

3. The immunogenic composition according to claim 1 or 2, wherein the water-soluble polyanionic polymer is a polyacrylic acid polymer, or a pharmaceutically acceptable salt thereof.

4. The immunogenic composition according to any one of claims 1-3, wherein the nucleic acid carrier is a lipid nanoparticle (LNP).

5. The immunogenic composition according to any one of claims 1-4, wherein the nucleic acid is an mRNA.

6. Immunogenic composition comprising: - at least one water-soluble polyanionic polymer, wherein said water-soluble polyanionic polymer is a polyacrylic acid polymer, or a pharmaceutically acceptable thereof, - at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, wherein said nucleic acid carrier is a lipid nanoparticle (LNP), and - at least one nucleic acid encoding at least one antigen, wherein said nucleic acid is an mRNA.

7. The immunogenic composition according to any one of claims 1-6, wherein the nucleic acid is at least partially encapsulated in the nucleic acid carrier.

8. The immunogenic composition according to any one of claims 1-7, wherein the water-soluble polyanionic polymer has a weight average molecular weight (Mw) in the range of 60 to 650 kDa.

9. The immunogenic composition according to any one of claims 1-8, wherein the water-soluble polyanionic polymer is a linear or branched polymer.

10. The immunogenic composition according to any one of claims 1-9, wherein the nucleic acid and the water-soluble polyanionic polymer are present in a w/w ratio from about 1:4000 to about 1:25.

11. The immunogenic composition according to any one of claims 1-10, wherein the immunogenic composition comprises from about 0.1 mg to about 4.0 mg of water-soluble polyanionic polymer per dose.

12. The immunogenic composition according to any one of claims 1-11, wherein the nucleic acid carrier is an LNP, said LNP comprising, further to the at least one cationic, or ionizable cationic, lipid, at least one stealth lipid, at least one structural lipid, and at least one helper lipid.

13. The immunogenic composition according to claim 12, wherein: - the cationic, or ionizable cationic, lipid is selected from the group consisting of OF-02, cKK-E10, GL-HEPES-E3-E10-DS-3-E18-1, GL-HEPES-E3-E12-DS-4-E10, GL-HEPES-E3- E12-DS-3-E14, IM-001, IS-001, ALC-0315, SM-102, MC3, and combinations thereof; - the stealth lipid is a PEGylated lipid, said PEGylated lipid comprising a PEG moiety being PEG2000 (or PEG-2K); - the structural lipid is cholesterol; and - the helper lipid is selected from the group consisting of 1,2-dioleoyl-SN-glycero-3- phosphoethanolamine (DOPE), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2- dielaidoyl-sn-glycero-3-phosphoethanolamine (DEPE), and combinations thereof.

14. Vaccine comprising a prophylactically effective amount or a therapeutically effective amount of the immunogenic composition according to any one of the preceding claims.

15. Kit-of-parts comprising at least a first container and at least a second container, wherein: - the first container comprises a first composition comprising at least one water-soluble polyanionic polymer, - the second container comprises a second composition comprising at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, and at least one nucleic acid encoding at least one antigen.

16. An immunogenic composition according to any one of claims 1-13 or a vaccine according to claim 14, for use in an immunization method.

17. The immunogenic composition for use according to claim 16, wherein the immunization method is for inducing an immune response with an antigen-encoding nucleic acid dose-sparing effect.

18. The immunogenic composition for use according to claim 17, wherein the composition comprises an amount of antigen-encoding nucleic acid at least 2 times lower than the amount of antigen-encoding nucleic acid of an immunogenic composition comprising the same nucleic acid carrier and the same nucleic acid and inducing a similar or comparable immune response in absence of the water-soluble polyanionic polymer.

19. Use of a water-soluble polyanionic polymer for obtaining an antigen-encoding nucleic acid dose-sparing effect in an immunization method, the water-soluble polyanionic polymer being included in an immunogenic composition comprising at least one nucleic acid carrier comprising at least one cationic, or ionizable cationic, lipid, and at least one nucleic acid encoding at least one antigen.

20. Use of a water-soluble polyanionic polymer for adjuvanting an immune composition, said immunogenic composition further comprising at least one nucleic acid carrier and at least one nucleic acid encoding at least one antigen.