Title: Antiviral vaccine composition FIELD OF THE INVENTION The invention is in the field of antiviral treatment, in particular to viral vaccines, and methods for preparing same. The present invention provides as an viral vaccine a combination of a protein or peptide antigen and an adjuvant. The present invention also provides novel adjuvant combinations. The invention also provides methods of treating or preventing viral infectious disease, using the vaccine and adjuvant combinations of the invention. BACKGROUND OF THE INVENTION So far, attempts to generate universal vaccines against seasonal viral infections, such as from SARS or influenza virus, have shown limited success due to their failure to stimulate strong T cell responses. This arises from the fact that soluble peptide/protein immunizations are weak inducers of cytotoxic CD8+ T cell (CTL) responses. Most viral vaccines provide protection not by stimulating killer CD8+ T cells against proteins of the virus but by generating neutralizing anti-viral antibodies against surface proteins of the virus (such as the anti-Spike protein in SARS-CoV-2 mRNA vaccines (Pfizer, Moderna) and adenovirus (Astrazeneca)). But RNA immunization also induces only weak T cell responses. Most current influenza virus vaccines also generate neutralizing anti-viral antibodies to target proteins on the surface of the virus that enable entry to host cells (hemagglutinin and neuraminidase). One example of a successful viral vaccine is the Yellow Fever vaccine that elicits CTL responses of ~2-10% and provides lifelong protection (Akondy RS, et al.2017 Nature 52(7685):362-367). Thus if clinically relevant T cell responses to viral antigens are to be achieve, there is a need for vaccine strategies that stimulate more T cell immunity. Proteins and peptides on their own are poor inducers of T cell immunity. This is a general problem relating to the immunogenicity of peptides or proteins when they are used in vaccines. Peptide-based vaccines exhibit inefficient co-delivery of antigenic peptides and adjuvants to draining lymph nodes (dLNs), and can have the adverse effect of inducing immunological tolerance and reduced CD8+ T cell immunity. To solve this problem, typical peptide vaccination protocols include conjugation of the peptides to a carrier protein or TLR agonists or present peptides in a multimeric format for co-delivery with an adjuvant (such multimeric formats include virus-like-particles, nanoparticle or liposomes). It would be beneficial if the antigen would not require special encapsulation such as used in the current SARS-CoV-2 mRNA vaccines (as required in the mRNA vaccines of Pfizer and Moderna) or the need to produce live viruses as the adenovirus vaccines do (Astrazeneca). This would greatly facilitate the production of vaccines, reduce costs and improve safety. It would also be beneficial if the vaccine would not only neutralize the virus and prevent infection as the conventional vaccines above do, but if it could accelerate the clearance of the virus and prevent spreading by killing infected cells before they make more virus particles. Thus there still remains a need to develop strategies that can stimulate potent CTL immunity when using peptides as targets of vaccination. One such strategy may arise from the development of novel adjuvants. An adjuvant is an immunopotentiator that is added to enhance the effect of a vaccine. With the recent development in immunology, the action mechanism of adjuvants has been gradually elucidated. Recently, various immunoregulatory properties of adjuvants are expected to be applied in the prevention or therapy of not only cancer and infections, but also allergies, cancer, and autoimmune diseases. Many vaccine adjuvants have been developed, mainly to induce antibody production (humoral immunity) up to this point. Many of the current adjuvants, including alum adjuvants are therefore humoral immunity inducing adjuvants called Th2 adjuvants (type II adjuvants). However, induction of cell-mediated immunity is more important than humoral immunity in the prevention or therapy of cancer or allergies. Such adjuvants are called Th1 adjuvants (type I adjuvants). Currently only 6 adjuvants have been approved for human use. These adjuvants are used with proteins or heat inactivated viruses (basically the proteins of the virus). These include aluminium salts (alum), oil-in-water emulsion squalene adjuvant MF59, AS01 (contains monophosphoryl lipid A plus saponin fraction QS-21), AS04 (contains alum plus monophosphoryl lipid A), AS03 (contains squalene plus vitamin E) and oligodeoxynucleotides CpG 1018. These adjuvants have been designed primarily to induce antibody-mediated protection and vary in their ability to induce CD4+ T cell immunity (Del Giudice, G., et al.2018. Semin Immunol 39, 14-21; Pulendran, B., et al.2021. Nat Rev Drug Discov 20, 454-475). Critically, the ability of these adjuvants to induce killer CD8+ T cell responses is much lower compared to viral vaccines (Akondy, R.S., et al. 2017. Nature 552, 362-367; Miller, J.D., et al.2008 Immunity 28, 710-722; Akondy, R.S., et al.2015. Proc Natl Acad Sci USA 112, 3050-3055). The present invention now aims to provide a vaccine composition comprising a viral peptide or protein antigen in combination with an adjuvant that allows targeting of proteins of the virus. The present invention also aims to provide a vaccine composition comprising a viral peptide or protein antigen in combination with an adjuvant that allows targeting of internal proteins in the virus structure (internal viral proteins), as these proteins are not subject to the same selective pressures during epidemics as viral surface proteins of, for example, SARS-CoV-2 and influenza virus, and thus do not mutate as fast. The present invention thus aims to provide a vaccine composition that raises T cell immunity against viral internal proteins so that it can provide a universal vaccine, i.e. a vaccine that recognizes and protects against many different strains of the virus, such as against the Delta and Omicron and future variants of SARS- CoV-2 or seasonal variant strains of influenza virus. SUMMARY OF THE INVENTION The present inventors have now found a therapeutic and prophylactic antiviral vaccine strategy comprising the use of a viral antigen in a vaccine composition adjuvated with a combination of a CpG oligonucleotide and a STING agonist. In particular, the inventors herein provide an adjuvant combination of a CpG oligonucleotide and a STING agonist, wherein the CpG oligonucleotide is K3 CpG and wherein the STING agonist is c-di-AMP. This adjuvant combination was found to induce a strong CTL immunity against viral protein and peptide antigens. The present inventors found that, in mice, a strong CTL immunity was raised against a 20 amino acid immunogenic model peptide antigen (OVA(252-271) (LEQLESIINFEKLTEWTSSN) having the 8 amino acid CTL epitope OVA _(257-264) (SIINFEKL)). Unexpectedly, the CTL immunity was induced without the need to employ nanoparticles, which nanoparticles had previously been considered necessary for proper cross-presentation of longer peptides such as the present 20 amino acid antigen when an adjuvant combination of a CpG oligonucleotide and a STING agonist is used. Thus the use of the adjuvant combination of a CpG oligonucleotide and a STING agonist unexpectedly circumvents the need to employ nanoparticles to cross-present longer peptides, something that greatly facilitates the production, storage and transport of vaccines for human use. Also, as outlined in the experimental part herein below, the same potent in vivo T cell immune response was observed in mice against a SARS-CoV-2 nucleocapsid (N) protein using a combination of K3 CpG and c- di-AMP as adjuvant. Importantly, while a strong Th1 and CTL immunity was shown, there was no induction of Th2 immunity (evidenced by absence of IL-5 producing T cells) against the antigens. The adjuvant combination of a CpG oligonucleotide and a STING agonist allows the use of viral protein or peptide antigens in a viral vaccine while inducing potent killer CD8+ T cell responses. The vaccine compositions of the present generate protection by stimulating killer CD8+ T cells against proteins or peptides of the virus and not by generating neutralizing anti-viral antibodies against surface proteins of the virus. The CTL immunity enhancing effect of the combination of K3 CpG and STING agonists is somewhat surprising as STING agonists can inhibit the ability of CpG TLR9 agonists like K3 CpG to induce type I IFN. Such type I IFN production is considered a critical signal 3 for the generation of efficient CTL immunity. The adjuvant combination offers the advantage that potent anti- viral T cell responses are generated using proteins or peptides. It does not require special encapsulation, conjugation or the need to produce live viruses. This greatly facilitates the production of vaccines, and further provides the ability to freeze dry the vaccine, meaning that cold-chain from the vaccine manufacturer to the vaccination site is no longer required. A freeze dried vaccine can be shipped and stored at room temperature, reducing transport and storage costs and increasing availability of the vaccine. In a first aspect, the present invention provides an antiviral vaccine composition, comprising a viral coat, matrix or core/capsid (glyco)protein as antigen, and an adjuvant combination of a CpG oligonucleotide and a STING agonist, optionally further comprising a pharmaceutically acceptable vehicle, preferably a non-particulate aqueous vehicle. In a preferred embodiment of an antiviral vaccine composition according to the present invention the antigen is not a viral surface protein. In another preferred embodiment of an antiviral vaccine composition according to the present invention the antigen is an internal viral protein. In another preferred embodiment of an antiviral vaccine composition according to the present invention the viral coat, matrix or core/capsid (glyco)protein is from a seasonal virus, including but not limited to coronavirus, influenza virus, respiratory syncytial virus (RSV), norovirus, rhinovirus, parainfluenza, and metapneumovirus, preferably coronavirus, influenza virus, and respiratory syncytial virus (RSV), more preferably Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and Influenza A and B virus. These viruses may be mammalian or avian variants, preferably human or avian, more preferably human. In another preferred embodiment of an antiviral vaccine composition according to the present invention the antigen is a SARS-CoV nucleocapsid (N) protein, preferably SARS-CoV-2 N protein. In another preferred embodiment of an antiviral vaccine composition according to the present invention CpG oligonucleotide is K3 CpG, and the STING agonist is c-di-AMP. In another preferred embodiment of an antiviral vaccine composition according to the present invention the composition is in lyophilized form. In another aspect, the present invention provides the antiviral vaccine composition according to the invention as described above, for use in the prevention or treatment of viral infection. In another aspect, the present invention provides a method of treating or preventing a viral infection, preferably a SARS infection, more preferably SARS-CoV-2 infection, in a subject in need thereof, comprising administering to said subject a therapeutically or prophylactically effective amount of an antiviral vaccine composition according to the invention as described above. In a preferred embodiment of a method of treating or preventing a viral infection according to the present invention, the antigen is a SARS nucleocapsid (N) protein, preferably SARS-CoV-2 N protein. In another preferred embodiment of a method of treating or preventing a viral infection according to the present invention, the CpG oligonucleotide is K3 CpG and the STING agonist is c-di-AMP. In another aspect, the present invention provides an antiviral vaccine adjuvant combination comprising K3 CpG and c-di-AMP. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows the result of Example 1, wherein mice were vaccinated 3 times with 2-week intervals with SARS-CoV-2 N protein and 10 µg of K3 CpG and 10 µg of c-di-AMP or controls, and wherein thirty days after last immunization with, splenocytes were stimulated in vitro with peptide pools (NC pool) that cover the full SARS-CoV-2 N protein. SARS- CoV-2 N protein plus K3 CpG + c-di-AMP vaccination induces strong memory in both CD4+ and CD8+ T cells as exemplified by the immune response against SARS-CoV-2 N protein of isolated splenocytes stimulated in vitro with peptide pools that cover the full SARS-CoV-2 N protein. The immune response was measured as the number of cells producing IFNγ after intracellular cytokine staining and flow cytometry. Each group contained 5 animals. Figure 2 shows the amino acid sequence of the nucleocapsid phosphoprotein (N protein), of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), Genbank Accession YP_009724397.2. Figure 3: K3 CpG + c-di-AMP adjuvant combination induces strong T cell responses against SARS-CoV-2 nucleocapsid protein (NC) as outlined in Example 3. (A) Time schedule of vaccination. C57BL/6 mice were subcutaneously immunized with 100 µl of saline, each vaccine containing SARS-CoV-2 nucleocapsid protein (NC) and Addavax, K3 CpG + c-di-AMP, or c-di-AMP alone, or lyophilized vaccine (lyo) containing NC and K3 CpG + c-di-AMP in the flank 3 times every two weeks as indicated the time schedule of vaccination. (B and C) IFN-γ ELISpot using PBMCs. On day 21 (week 3), day 35 (week 5), and day 56 (week 8), blood was obtained for ELISpot analysis. The number of NC-specific T cells producing IFN-γ were measured by ELISpot after 24 hours of restimulation of PBMCs with NC protein peptide mix. Each dot represents an individual mouse. SPFC/SFC: spot forming cells. Figure 4: K3 CpG + c-di-AMP adjuvant combination induces potent memory CD4+ and CD8+ T cell immunity against SARS-CoV-2 nucleocapsid protein (NC) as outlined in Example 3. C57BL/6 mice were immunized subcutaneously with 100 µl of saline, each vaccine containing SARS-CoV-2 nucleocapsid protein (NC) and Addavax, K3 CpG + c-di-AMP, or c-di-AMP alone, or lyophilized (lyo) vaccine containing NC and K3 CpG + c-di-AMP in the flank 3 times every two weeks as indicated the time schedule of vaccination. (A, B) At 28 days after last vaccine boost (week 8 of experiment), the mice were euthanized and spleens were obtained for analysis. To assess Th1 and Th2 immunity against SARS-CoV-2 nucleocapsid protein, the number of NC-specific T cells producing IFN-γ and IL-5 were measured by ELISpot after 24 hrs of restimulation of splenocytes with NC protein peptide mix (A). The frequencies of IFN-γ producing NC- specific CD8+ and CD4+ T cells were analyzed by intracellular staining after restimulation with NC protein (B). Each dot represents an individual mouse. SFC: spot forming cells. Figure 5: A vaccine including SARS-CoV-2 nucleocapsid protein (NC) and K3 CpG + c-di-AMP adjuvant combination protects mice against SARS-CoV-2 viral challenge as outlined in Example 3. A) Vaccination and viral challenge schedule in K18-hACE2 transgenic mice. B) Survival curves for mice vaccinated and then intranasally challenged with 10 ⁴ PFU SARS- CoV2 Wuhan strain (Wu-Hu-1) 50µl in DMEM. Only mice vaccinated with SARS-CoV-2 NC protein plus K3 CpG and c-di-AMP (NC/K3/c-di-AMP) in 100 µl of sterile saline are protected. Unvaccinated (saline vaccination) controls animals or animals vaccinated with SARS-CoV-2 NC protein in AddaVax (NC/Addavax) were not protected. Animals vaccinated with ovalbumin protein (OVA) plus K3 CpG and c-di-AMP (OVA/K3/c-di-AMP) were also not protected. DETAILED DESCRIPTION OF THE INVENTION The definition of the terms and/or general techniques particularly used herein is explained hereinafter, as appropriate. As used herein, “CpG oligonucleotide”, “CpG oligodeoxynucleotide”, “CpG ODN”, or “simply “CpG” are interchangeably used, and refer to a polynucleotide, preferably an oligonucleotide, comprising at least one non-methylated CG dinucleotide sequence. An oligonucleotide comprising at least one CpG motif may comprise multiple CpG motifs. As used herein, the phrase “CpG motif” refers to a non- methylated dinucleotide moiety of an oligonucleotide, comprising a cytosine nucleotide and a subsequent guanosine nucleotide.5-methylcytosine may also be used instead of cytosine. A CpG oligonucleotide (CpG ODN) is a short (about 20 base pairs) synthetic single-stranded DNA fragment comprising an immunostimulatory CpG motif. A CpG oligonucleotide is a potent agonist of a toll-like receptor 9 (TLR9), which activates dendritic cells (DCs) and B cells to produce type I interferons (IFNs) and inflammatory cytokines (Hemmi, H., et al. Nature 408, 740-745 (2000); Krieg, A. M. Nature reviews. Drug discovery 5, 471-484 (2006).), and acts as an adjuvant of Th1 humoral and cell-mediated immune responses, including cytotoxic T-lymphocyte (CTL) reactions (Brazolot Milian, C. L, Weeratna, R., Krieg, A. M., Siegrist, C. A. & Davis, H. L. Proceedings of the National Academy of Sciences of the United States of America 95, 15553-15558 (1998).; Chu, R. S., Targoni, O. S., Krieg, A. M., Lehmann, P. V. & Harding, C. V. The Journal of experimental medicine 186, 1623-1631 (1997)). In this regard, CpG ODN has been considered a potential immunotherapeutic agent against inflammation, cancer, asthma, and hay fever (Krieg, A. M. Nature reviews. Drug discovery 5, 471-484 (2006); Klinman, D. M. Nature reviews. Immunology 4, 249-258 (2004)). A CpG oligodeoxynucleotide (CpG ODN) is a synthetic single stranded DNA comprising a non-methylated CpG motif with a immunostimulatory feature due to similarity with a microbial genome, and is recognized by TLR9 in a specific type of natural immune cell [Hartmann et al., J. Immunol. (2000) 164: 944-953; Wagner et al., Trends Immunol. (2004) 25: 1-6]. In ligand binding, TLR9 signals through an adapter molecule myD88 to induce the production of IRF7 dependent type I IFN and NF-κB dependent cytokines [Krieg et al., Nat. Rev. Drug Discov. (2006) 5: 471-84] Furthermore, it is reported that CpG ODN induces a Th1 response due to the type of cytokine induced by CpG ODN in APC in vivo [Krieg et al., Nat. Rev. Drug Discov. (2006) 5: 471-84]. Among different types of CpG ODN, type D CpG ODN strongly induces both type I and type II IFN, but cannot induce B cell activation [Krieg et al., Nat. Rev. Drug Discov. (2006) 5: 471-84; Klinman et al., Nat. Rev. Immunol. (2004) 4:1-10]. Type K CpG ODN (K3 CpG) strongly induces B cell activation to induce IL-6 and antibody production, but they only weakly induce type I and type II IFN. However, type D CpG ODN forms an aggregation, such that only type K CpG can be used for clinical applications [Krieg et al., Nat. Rev. Drug Discov. (2006) 5: 471-84; Klinman et al., Nat. Rev. Immunol. (2004) 4: 1-10]. Pathogen derived agents such as LPS or non-methylated CpG DNA (CpG) (CpG ODN) stimulate natural immune cells that produce cytokines such as type I or type II IFN and IL-12. This is useful in inducing a Th1 response and cell-mediated immunity [Kawai et al., Immunity. (2011) 34: 637-650; Trinchieri et al., Immunol. (2007) 7: 179-190]. IL-12 acts on naïve CD4 ⁺ T cells to derive the generation of Th1 and the production of IFNγ [Seder et al., Proc. Natl. Acad. Sci. U.S.A. (1993) 90: 10188-92; Hsieh et al., Science. (1993) 260: 547-579]. In addition, IFNγ producing Th1 cells are the main actors in the induction of type 1 immunity, which are distinguished by high phagocytic activity [Spellberg et al., Clin. Infect. Dis. (2001) 90509: 76-102; Mantovani et al., Curr. Opin. Immunol. (2010) 22: 231-237]. Furthermore, Th1 cells play an important role in the generation of antitumor immunity and are useful in CTL effector functions and suitable activation including IFNγ production [Hung et al., J. Exp. Med. (1998) 188: 2357-68; Vesely et al., Annu. Rev. Immunol. (2011) 29: 235-271]. Thus, agents, CTLs, and NK cells that can induce a strong Th1 response [Vitale et al., Eur. J. Immunol. (2014) 44: 1582-1592] may play an important role in the development of a vaccine adjuvant or immunotherapeutic agent that is effective against intracellular pathogens or cancer. Therefore, they are in immediate demand. Depending on the difference in backbone modification or surrounding sequences, they are classified into type D/A, type K/B, type C, and type P (Vollmer, J. & Krieg, A. M. Advanced drug delivery reviews 61, 195-204 (2009).) It is suggested that type D/A induces the production of type I interferon mainly from plasmacytoid dendritic cells (called “plasmacytoid DC” or “pDC”), and type K/B induces B cell growth and the production of IgM, IL-6 or the like. Type D/A CpG-DNA strongly induces IFN-α production, but exhibits low pDC maturation inducing activity and no direct immunostimulatory activity to B cells. Type K/B exhibits immunostimulatory activity to B cells, strongly promotes maturation of pDCs, and has high IL-12 inducing capability, but has low IFN-α inducing capability. In type C sequences having repetitive sequences of TCG that are completely thiolated, IFN-α production by pDCs or polyclonal B cell activation is induced. Type D/A CpG ODN (also called type A, type D or the like and denoted as CpG-A ODN) is an oligonucleotide characterized by a phoshothioate (PS) bond at the 5′ and 3′ terminuses and by a poly G motif with a palindrom (palindromic structure) CpG containing sequence of phosphodiester (PO) in the middle. Cell uptake is facilitated due to the presence of phosphorothioate (PS) at the 5′ and 3′ terminuses. CpG type D/A produces a large quantity of interferon α (IFN-α) in pDCs (different feature from CpG type K/B). A potent activation and interferon gamma production are induced thereby in NK cells and γδ T cells. However, B cells are not activated and pDCs are not matured (Krug, A., et al. European journal of immunology 31, 2154-2163 (2001).; and Verthelyi, D., et al. Journal of immunology 166, 2372-2377 (2001).) Three other types of ODN consist of a PS backbone. Type K/B CpG ODN is also called CpG-type B or CpG-type K. All type K/B CpG ODN with one or more CpG motifs without a poly G motif have a phosphorothioate (PS) backbone. Typically, type K/B CpG ODN contains multiple CpG motifs with a non-palindromic structure. Type K/B CpG has weak IFN-α inducing activity (produces nearly none), but is a very potent Th1 adjuvant and a potent B cell response stimulating agent which produces IL-6 and activates and matures pDCs (Verthelyi, D., et al. Journal of immunology 166, 2372-2377 (2001); and Hartmann, G. & Krieg, A. M. Journal of immunology 164, 944-953 (2000)). Type K/B CpGODN has a function of promoting the survival, activating, and maturing both monocyte derived dendritic cells and pDCs. Recently developed type C and type P CpG ODN comprise one and two palindromic structure CpG sequences, respectively. Both can activate B cells, like type K CpG ODN, and activate pDCs, like type D CpG ODN. Meanwhile, type C CpG ODN more weakly induces IFN-α production relative to type P CpG ODN (Hartmann, G., et al. European journal of immunology 33, 1633-1641 (2003); Marshall, J. D., et al. Journal of leukocyte biology 73, 781-792 (2003).; and Samulowitz, U., et al. Oligonucleotides 20, 93-101 (2010)). Type D/K and type P CpG ODN are shown to form a higher order structure i.e., Hoogsteen base pair forming a four parallel strand structure called G-tetrads and Watson-Crick base pair between a cis palindromic structure site and a trans palindromic structure site, respectively, which are required for potent IFN-α production by pDCs (Samulowitz, U., et al. Oligonucleotides 20, 93-101 (2010).; Kerkmann, M., et al. The Journal of biological chemistry 280, 8086-8093 (2005).; and Klein, D. et al. Ultramicroscopy 110, 689-693 (2010)). Due to the higher order structure, only type K and type C CpG ODN are generally considered usable as immunotherapeutic agents and vaccine adjuvants for humans (Puig, M., et al. Nucleic acids research 34, 6488-6495 (2006); Bode, C., et al. Expert review of vaccines 10, 499-511 (2011); and McHutchison, J. G., et al. Hepatology 46, 1341-1349 (2007)). In contrast to type A CpG ODN, type C CpG ODN has a complete phosphorothioate (PS) backbone without a poly G motif, but comprises the type A palindromic sequence of CpG in combination with a stimulatory CpG motif. It is reported from an in vivo study that type C CpG ODN is a very potent Th1 adjuvant. Type K CpG ODN used in a preferred embodiment in the present invention has a length of 10 nucleotides or longer and comprises the nucleotide sequence set forth in the following formula: 5′-N ₁ N ₂ N ₃ T-CpG-WN ₄ N ₅ N ₆ -3′ [Formula 1] wherein the middle CpG motif (described as CpG) is not methylated, W is A or T, and N1, N2, N3, N4, N5, and N6 may be any nucleotide. In one embodiment, type K CpG ODN of the invention has a length of 10 nucleotides or longer and comprises the nucleotide sequence of the above-described formula. However, in the above-described formula, the CpG motif of 4 bases in the middle (TCpGW) only needs to be included in the 10 nucleotides. The motif does not necessarily need to be positioned between N3 and N4 in the above-described formula. Further, the N1, N2, N3, N4, N5, and N6 may be any nucleotide in the above-described formula. Combinations of at least one (preferably one) of N1 and N2, N2 and N3, N3 and N4, N4 and N5, and N5 and N6 may be a two base CpG motif. When the four base CpG motif is not positioned between N3 and N4, any two contiguous bases in the middle 4 bases (4th to 7th bases) in the above- described formula may be a CpG motif and the other two bases may be any nucleotide. Further, a part of or the entire phosphodiester bond of an oligodeoxynucleotide may be substituted with a phosphorothioate bond. Preferably, the entire phosphodiester bond of an oligodeoxynucleotide is substituted with a phosphorothioate bond. Type K CpG ODN suitably used in the present invention contains a non-palindromic structure comprising one or more CpG motifs. Type K CpG ODN more suitably used in the present invention consists of a non- palindromic structure comprising 1 or more CpG motifs. Type K CpG ODN contained in the oligodeoxynucleotide of the invention is preferably humanized. “Humanized” refers to having agonistic activity against human TLR9. Thus, the oligodeoxynucleotide of the invention comprising humanized type K CpG ODN has immunostimulatory activity unique to type K CpG ODN against humans (e.g., activity to activate human B cells to produce IL-6). Humanized type K CpG ODN is generally characterized by a four base CpG motif consisting of TCGA or TCGT. In many cases, a single humanized type K CpG ODN comprises 2 or 3 of the four base CpG motifs. Thus, in a preferred embodiment, type K CpG ODN contained in the oligodeoxynucleotide of the invention comprises at least 1, more preferably 2 or more, and still more preferably 2 or 3 four base CpG motifs consisting of TCGA or TCGT. When such type K CpG ODN has 2 or 3 four base CpG motifs, these four base CpG motifs may be the same or different. However, this is not particularly limited, as long as there is agonist activity against human TLR9. One preferred type K CpG ODN included in the aspects of the invention comprises the nucleotide sequence set forth in the sequence (atcgactctc gagcgttctc (SEQ ID NO: 1)). Other suitable CpG ODNs include CpG 1826 (5′- tccatgacgttcctgacgtt-3′ (SEQ ID NO: 2)), D35 CpG (5′-ggtgcatcgatgcagggggg- 3′ (SEQ ID NO: 3)), and the like. One particularly preferred type K CpG ODN included in the aspects of the invention comprises the nucleotide sequence set forth in the sequence (atcgactctc gagcgttctc (SEQ ID NO:1)). Most preferably, the CpG ODN consists of SEQ ID NO:1 and is herein referred to as K3 CpG. The length of type K CpG ODN is not particularly limited, as long as the oligodeoxynucleotide of the invention activates immunostimulatory activity (e.g., activity to activate B cells (preferably human B cells) to produce IL-6) or has anticancer activity, but the length is preferably 100 nucleotides long or less (e.g., 10 to 75 nucleotides long). The length of type K CpG ODN is more preferably 50 nucleotides long or less (e.g., 10 to 40 nucleotides long). The length of type K CpG ODN is still more preferably 30 nucleotides long or less (e.g., 10 to 25 nucleotides long). The length of type K CpG ODN is most preferably 12 to 25 nucleotides long. “STING” ((adapter molecule) stimulator of interferon genes)) identified as a membrane protein localized in the endoplasmic reticulum plays an important role in the biological defense mechanism against infections of various RNA viruses and DNA viruses. It is also reported that STING plays an important role in inducing natural immune responses against DNA components derived from microbes and viruses, but the molecular mechanism thereof had not been elucidated. STING can form a complex with not only genomic DNA derived from viruses, but also synthetic double stranded DNA of 45 to 90 base pairs called ISD and self-DNA components derived from apoptotic cells. Analysis of DNA interaction region in vitro demonstrated that the C-terminus side region of STING is important. Recognition of various DNA components by STING was demonstrated to induce dynamic local change to regions surrounding the nuclear membrane of STING and to induce interferon production via activation of TBK1. It is also suggested that STING is possibly involved in the regulation of chronic inflammatory responses via recognition of not only allo-DNA component from a microorganism, but also auto-DNA component. As used herein, a “STING ligand” and “STING agonist” are interchangeably used, which is a ligand (agonist) of “STING” ((adapter molecule) stimulator of interferon genes)) inducing type I IFN production and NF-κB mediated cytokine production. STING agonists are considered to be membrane proteins localized in the endoplasmic reticulum. As STING agonists, in addition to cGAMP, cyclic dinucleotides of microbial origin, c-di- AMP and c-di-GMP, are ligands of adapter molecule stimulators of IFN genes (STING), which signal through the TBK1-IRF3 axis to induce type I IFN production and NF-κB mediated cytokine production [Burdette et al., Nature. (2011) 478: 515-8; Mcwhirter et al., J. Exp. Med. (2009) 206: 1899- 1911]. Recent studies report that these cyclic dinucleotides function as a potent vaccine adjuvant due to their ability to enhance antigen-specific T cells and humoral immune responses. Despite the above, the inventors' group has previously found that a STING agonist, DMXAA, unexpectedly induces a type 2 immune response via STING-IRF3 mediated type I IFN production [Tang et al., PLoS One. (2013) 8: 1-6]. Since type 2 immune responses can inhibit a type 1 immune response, the clinical usefulness of STING agonists, including cyclic dinucleotides, was debatable. For instance, the most common adjuvant, aluminum salt (alum), lacks the ability to induce cell-mediated immunity, which is understood to protect against cancer or diseases from intracellular pathogens [Hogenesch et al., Front. Immunol. (2013) 3: 1-13]. To overcome this limitation, alums were combined with many different types of adjuvants including monophosphoryl lipid A [Macleod et al., Proc. Natl. Acad. Sci. U.S.A (2011) 108: 7914-7919] and CpG ODN [Weeratna et al., Vaccine. (2000) 18: 1755-1762]. In regard to the techniques related to STING, especially when host DNA is unsuitably present in cytosol, host DNA may also be a sign of danger as in microorganism DNA, which results in interferon and inflammatory cytokine production [Desmet et al., Nat. Rev. Immunol. (2012) 12: 479-491; Barber et al., Immunol. Rev. (2011) 243: 99-108]. A recently identified cytosol DNA sensor is a cyclic GMP-AMP synthase (cGAS), which catalyzes the production of nonstandard cyclic dinucleotide cGAMP (2′3′-cGAMP) and contains a nonstandard 2′,5′ bond and 3′,5′ bond with the purine nucleoside thereof [Sun et al., Science. (2013) 339: 786-91]. Standard cGAMP (3′3′) is synthesized in a microbe and has more variety of bonds than mammalian 2′3′-cGAMP. GMP and AMP nucleosides bind by a bis-(3′,5′) bond [Wu et al., Science. (2013) 339: 826-30; Zhang et al., Mol. Cell. (2013) 51: 226-35]. Thus, examples of STING agonists that can be used in the present invention include cyclic dinucleotides (CDN) such as 2′3′-cGAMP, c-di-AMP, 3′3′-cGAMP, and 3′2′-cGAMP, xanthenone derivatives such as DMXAA, and the like. STING agonists are also explained in WO 2010/017248, whose entire content is incorporated herein by reference. In preferred embodiments of the present invention, the STING agonists is c-di-AMP. Cyclic di-adenosine monophosphate (c-di-AMP) is a second messenger used in signal transduction in bacteria. As used herein, an “adjuvant” refers to an immunopotentiator that is added to increase the effect of a vaccine, which is an agent that is not a constituent of a specific antigen but increases immune responses to the administered antigen. The term “combination” as used herein is to be understood as referring to simultaneous, separate or sequential administration. In one aspect of the invention “combination” refers to simultaneous administration. In another aspect of the invention “combination” refers to separate administration. In a further aspect of the invention “combination” refers to sequential administration. Where the administration is sequential or separate, the delay in administering the second component is preferably such that both agents are present in the body so as to produce the effect of the combination. Hence, in aspects of this invention, a combination of two agents (a vaccine and an ICI; a vaccine and an adjuvant; a combination of two agents forming an adjuvant (CpG oligonucleotide and STING agonist) may be administered concomitantly, at different times, as part of the same formulation, as a combination of different formulations, in order, or separately. The term “allergy”, as used herein, refers to excessive immune responses to a specific antigen. Antigens from the environment causing allergies are especially called allergens. An “allergic disease” refers to a disease induced by an immune response to an exogenous antigen. However, this antigen is often harmless in a quantity that a patient is exposed to in normal life (e.g., pollen during spring time does not have toxicity in and of itself). An immune response resulting in unnecessary discomfort is experienced therewith. This is also called an allergic disease. Examples of typical diseases include atopic dermatitis, allergic rhinitis (hay fever), allergic conjunctivitis, allergic gastroenteritis, bronchial asthma, childhood asthma, food allergy, drug allergy, and hives. Recently, pathological conditions exhibiting a type 1 allergy symptom such as asthma or facial flash only from the scent of citrus or fragrance of gum or the like has drawn attention. The term “N protein” refers to a viral nucleocapsid protein. The nucleic acid and proteins of each class of viruses assemble themselves into a structure called a nucleoprotein, or nucleocapsid. The nucleocapsid protein (N protein) is the most abundant protein in coronavirus. The N protein is a highly immunogenic phosphoprotein, and it is normally very conserved. The term N protein, in aspects of this invention, preferably refers to a coronavirus nucleocapsid protein, still more preferably to a SARS nucleocapsid (N) protein, and most preferably the SARS-CoV-2 N protein as displayed in Figure 2, or sequences having at least 70%, 80%, 90%, 95% or at least 99% sequence similarity with the sequence of Figure 2, determined over the entire length of the protein. Antiviral vaccination Cytotoxic T lymphocytes (CTLs) are key players in the immune control of cancer and (viral or bacterial) infection, as they recognize cancer or pathogen derived peptide epitopes presented by HLA class I molecules on the cancer cell or infected cell surface The antiviral vaccine strategy provided by the present invention targets the immune system against specific antigens in cancer. It achieves this by combining the viral antigen with a CpG oligonucleotide and a STING agonist as adjuvants. The present inventors are the first to show that this adjuvant combination can induce potent CTL responses in vivo. In particular, the combination of the adjuvants K3 CpG and c-di-AMP is preferred herein. The adjuvants and antigen may be used in solution, i.e. they do not need to be presented in the form of nanoparticles. Adjuvants and antigen may be used in solution without adjuvants and antigen being conjugated to each other, nor peptides to be conjugated to carrier proteins. Adjuvants and antigen in solution do not need to be encapsulated in lipid or viral-like particles. In fact, the use of this adjuvant combination makes the use of nanoparticles, lipid particles, viral-like particles or conjugations to achieve cross-presentation and immunogenicity redundant. The use of the CpG oligonucleotide and a STING agonist combination, promotes cross- presentation while stimulating strong CTL immunity. This solves a major hurdle in viral peptide vaccination as it stimulates very strong CTL responses to peptides that otherwise need cross-presentation. The term “cross-presentation”, as used herein, refers to the process by which exogenous antigens captured by phagocytic antigen- presenting cells (APCs) are processed and presented onto MHC-I molecules. The vaccine compositions provided herein solves the problem of inducing cross-presentation without the need to generate modified or conjugated peptides or nanoparticles, lipid particles or viral-like particles in order to enhance uptake by APCs. Such modified peptides or nanoparticles would make it much more difficult to produce the vaccine composition under Good Manufacturing Practice (GMP) conditions, due to the chemicals required and complex production process. The presently provided vaccine composition requires only 3 components that can be mixed in aqueous solution, such as saline, and is easy to prepare and administer. These 3 components can be lyophilized together greatly facilitating the storage and transport of the vaccine without the need of a cold chain. Such a lyophilized vaccine can be reconstituted with sterile water just before usage. The adjuvant combination described in the present invention can be used with peptides such as synthetic long peptides (e.g., having a length of 10-30 consecutive amino acids) and solves the problem of immunogenicity when using peptides in vaccines. The inventors have shown this effect inter alia by using a 20 amino acid OVA peptide LEQLESIINFEKLTEWTSSN as described in co-pending international application claiming priority from EP22386021.4. Peptide-based vaccines exhibit inefficient co-delivery of antigenic peptides and adjuvants to draining lymph nodes (dLNs), and can have the adverse effect of inducing immunological tolerance and reduced CD8+ T cell immunity. To solve this problem typical peptide vaccination protocols, conjugate peptides to a carrier protein or TLR agonists or present peptides in a multimeric format for co-delivery with adjuvant (such multimeric formats include virus-like-particles, nanoparticle or liposomes). The adjuvant combination described in the present invention can be used with peptides in solution to induce strong T cell immunity therefore avoiding the need for conjugations and multimeric particles. This is an important advantage as it simplifies manufacturing and safety concerns associated with conjugated molecules and multimeric particles. The vaccine compositions of the present invention overcome this problem and allow the use of such relatively long peptides, similarly without exact knowledge of the 8-10 amino acid sequence that is loaded in the MHC- class I complex, whereby efficient cross-presentation of these longer peptides is achieved by using a CpG oligonucleotide and a STING agonist as adjuvants, preferably, the combination of the adjuvants K3 CpG and c-di- AMP. In some vaccines K3 CpG may be substituted with humanized K3 CpG. Adjuvant combination One highly preferred adjuvant combination of a CpG oligonucleotide and a STING agonist as adjuvants is K3 CpG and c-di-AMP. This adjuvant combination is one aspect of this invention. The adjuvant combination may very suitably be used in combination with cancer neoantigens in (a vaccine for use in) the treatment of cancer. In embodiments, the invention provides the use of a combination of (humanized) K3 CpG oligonucleotide and c-di-AMP as adjuvants together with a short peptide 10-30 amino acid long as antigen. These peptides can be derived from tumor neoantigens. The adjuvant combination may very suitably be used in combination with allergen immunotherapy, also known as desensitization or hypo-sensitization. Allergen-specific Immunotherapy (AIT) is the only available treatment aimed to tackle the underlying causes of allergy. The active components of subcutaneous vaccines traditionally consist of natural or modified allergen extracts which can be combined with adjuvant platforms. In aspects of this invention the adjuvant platform comprising the combination of K3 CpG and c-di-AMP is provided. The adjuvant combination may very suitably be used in combination with antigenic peptides from pathogens in the preparation of a vaccine that can be used to stimulate immunity against viruses, bacteria etc. Antiviral vaccine compositions The present invention provides antiviral vaccine compositions comprising a viral coat, matrix or core/capsid (glyco)protein as antigen, and further comprising as adjuvants a CpG oligonucleotide and a STING agonist. Preferably the CpG oligonucleotide is K3-CpG and the STING agonist is c-di-AMP. The present inventors have found that splenocytes of animals vaccinated with a vaccine comprising a SARS-CoV-2 nucleocapsid (N) protein as antigen and the K3 CpG + c-di-AMP combination as adjuvant, induced very strong IFNγ CD4 and CD8 T cell responses when restimulated with peptides that cover the full length N protein but no Th2 T cell responses. These Th1 and cytotoxic CD8 T responses are considered protective while Th2 responses are considered detrimental (See Examples). The antiviral vaccine composition herein provided may also provide protection or treatment of other viral infectious diseases such as influenza (flu) caused by influenza viruses. The adjuvant combination of K3 CpG + c-di-AMP may be applied to viral vaccines in general, using any viral coat, matrix or core/capsid (glyco)protein as the antigen. The present invention further provides an antiviral vaccine composition comprising the adjuvant combination of K3 CpG + c-di-AMP, wherein the antigen is a SARS nucleocapsid (N) protein, preferably SARS- CoV-2 N protein. An antiviral vaccine composition in aspects of the invention comprises a viral coat, matrix or core/capsid (glyco)protein as antigen, and further comprising as adjuvants a CpG oligonucleotide and a STING agonist, preferably the antigen is a viral nucleocapsid protein, more preferably a SARS nucleocapsid (N) protein, even more preferably a SARS- CoV-2 N protein. A highly preferred embodiment of the CpG oligonucleotide and a STING agonist combination is in aspects of this invention is the combination K3 CpG + c-di-AMP. The present invention also provides a method of treating or preventing a viral infection, preferably a SARS infection, more preferably SARS-CoV-2 infection, comprising administrating to a subject in need thereof a therapeutically or prophylactically effective amount of a vaccine composition as described above comprising a viral coat, matrix or core/capsid (glyco)protein as the antigen. Medicaments and Dosage Forms The present invention is provided as medicaments (therapeutic agent or prophylactic agent) in various forms described above. The route of administration of a therapeutic agent, prophylactic agent, or the like that is effective upon therapy is preferably used, such as intravenous, subcutaneous, intramuscular, intraperitoneal, oral administration, or the like. Examples of dosage form include injection, capsules, tablets, granules, and the like. The components of the present invention are effectively used upon administration as an injection. Aqueous solutions for injection may be stored, for example, in a vial or a stainless steel container. Aqueous solutions for injections may also be blended with, for example, saline, sugar (e.g., trehalose), NaCl, NaOH, or the like. Therapeutic agents may also be blended, for example, with a buffer (e.g., phosphate buffer), stabilizer, or the like. In general, the composition, medicament, therapeutic agent, prophylactic agent, or the like of the present invention comprises a therapeutically effective amount of a therapeutic agent or effective ingredient, and a pharmaceutically acceptable carrier or excipient. As used herein, “pharmaceutically acceptable” means that a substance is approved by a government regulatory agency or listed in the pharmacopoeia or other commonly recognized pharmacopoeia for use in animals, more specifically in humans. As used herein “carrier” refers to a diluent, adjuvant, excipient or vehicle administered with a therapeutic agent. Such a carrier can be an aseptic liquid such as water or oil, including, but not limited to, those derived from petroleum, animal, plant or synthesis, as well as peanut oil, soybean oil, mineral oil, sesame oil, and the like. When a medicament is orally administered, water is a preferred carrier. For intravenous administration of a pharmaceutical composition, saline and aqueous dextrose are preferred carriers. Preferably, an aqueous saline solution and aqueous dextrose and glycerol solution are used as a liquid carrier of an injectable solution. Suitable excipients include light anhydrous silicic acid, crystalline cellulose, mannitol, starch, glucose, lactose, sucrose, gelatin, malt, rice, wheat flour, chalk, silica gel, sodium stearate, glyceryl monostearate, talc, sodium chloride, powdered skim milk, glycerol, propylene, glycol, water, ethanol, carmellose calcium, carmellose sodium, hydroxypropyl cellulose, hydroxypropyl methylcellulose, polyvinyl acetal diethylamino acetate, polyvinylpyrrolidone, gelatin, medium-chain fatty acid triglyceride, polyoxyethylene hydrogenated castor oil 60, saccharose, carboxymethylcellulose, corn starch, inorganic salt, and the like. When desirable, the composition can also contain a small amount of wetting agent, emulsifier, or pH buffer. These compositions can be in a form of a solution, suspension, emulsion, tablet, pill, capsule, powder, sustained release preparation, or the like. It is also possible to use traditional binding agents and carriers, such as triglyceride, to prepare a composition as a suppository. Oral preparation can also comprise a standard carrier such as medicine grade mannitol, lactose, starch, magnesium stearate, sodium saccharin, cellulose, or magnesium carbonate. Examples of a suitable carrier are described in E. W. Martin, Remington's Pharmaceutical Sciences (Mark Publishing Company, Easton, U.S.A.). Such a composition contains a therapeutically effective amount of therapy agent, preferably in a purified form, together with a suitable amount of carrier, such that the composition is provided in a form suitable for administration to a patient. A preparation must be suitable for the administration format. In addition, the composition may comprise, for example, a surfactant, excipient, coloring agent, flavoring agent, preservative, stabilizer, buffer, suspension, isotonizing agent, binding agent, disintegrant, lubricant, fluidity improving agent, corrigent, or the like. Examples of “salt” in one embodiment of the present invention include anionic salts formed with any acidic (e.g., carboxyl) group and cationic salts formed with any basic (e.g., amino) group. Salts include inorganic salts and organic salts, as well as salts described in, for example, Berge et al., J. Pharm. Sci., 1977, 66, 1-19. Examples thereof further include metal salts, ammonium salts, salts with organic base, salts with inorganic acid, salts with organic acid, and the like. “Solvate” in one embodiment of the present invention is a compound formed with a solute or solvent. For example, J Honig et al., The Van Nostrand Chemist's Dictionary P650 (1953) can be referred for solvates. When a solvent is water, a solvate formed thereof is a hydrate. It is preferable that the solvent does not obstruct the biological activity of the solute. Examples of such a preferred solvent include, but not particularly limited to, water and various buffers. Examples of “chemical modification” in one embodiment of the present invention include modifications with PEG or a derivative thereof, fluorescein modification, biotin modification, and the like. When the present invention is administered as a medicament, various delivery systems are known, which can be used to administer the agent of the invention to a suitable site (e.g., esophagus). Examples of such a system include use of a recombinant cell that can express encapsulated therapeutic agent (e.g., polypeptide) in liposomes, microparticles, and microcapsules; use of endocytosis mediated by a receptor; construction of a therapy nucleic acid as a part of a retrovirus vector or another vector; and the like. Examples of the method of introduction include, but are not limited to, intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, intranasal, epidural, and oral routes. A medicament can be administered by any suitable route, such as by injection, bolus injection, or by absorption through epithelial or mucocutaneous lining (e.g., oral cavity, rectum, intestinal mucosa, or the like). In addition, an inhaler or mistifier using an aerosolizing agent can be used as needed. Moreover, other biological activating agents can also be administered concomitantly. Administration can be systemic or local. When the present invention is used for cancer, the present invention can be administered by any suitable route such as direct injection into cancer (lesion). In a preferred embodiment, a composition can be prepared as a pharmaceutical composition adapted to administration to humans in accordance with a known method. Such a composition can be administered by an injection. A composition for injection is typically a solution in an aseptic isotonic aqueous buffer. A composition can also comprise a local anesthetic such as lidocaine, which alleviates the pain at the site of injection, and a solubilizing agent as needed. Generally, ingredients can be supplied individually or by mixing the ingredients together in a unit dosage form; and supplied, for example, in a sealed container such as an ampoule or sachet showing the amount of active agent or as a lyophilized powder or water-free concentrate. When a composition is to be administered by injection, the composition can be distributed using an injection bottle containing aseptic agent-grade water or saline. When composition is to be administered by injection, an aseptic water or saline ampoule for injection can also be provided such that the ingredients can be mixed prior to administration. The composition, medicament, therapeutic agent, and prophylactic agent of the invention can be prepared as a neutral or base form or other prodrugs (e.g., ester or the like). Pharmaceutically acceptable salts include salts formed with a free carboxyl group, derived from hydrochloric acid, phosphoric acid, acetic acid, oxalic acid, tartaric acid, or the like, salts formed with a free amine group, derived from isopropylamine, triethylamine, 2-ethylaminoethanol, histidine, procaine, or the like; and salts derived from sodium, potassium, ammonium, calcium, ferric hydroxide or the like. The amount of therapeutic agent of the invention that is effective in therapy of a specific disorder or condition may vary depending on the properties of the disorder or condition. However, such an amount can be determined by those skilled in the art with a standard clinical technique based on the descriptions herein. Furthermore, an in vitro assay can be used in some cases to assist the identification of the optimal dosing range. The precise dose to be used for a preparation may also vary depending on the route of administration or the severity of the disease or disorder. Thus, the dose should be determined in accordance with the judgment of the attending physician or the condition of each patient. The dosage is not particularly limited, but may be 0.001, 1, 5, 10, 15, 100, or 1000 mg/kg body weight per dosage or within a range between any two values described above. The dosing interval is not particularly limited, but may be, for example, 1 or 2 doses every 1, 7, 14, 21, or 28 days or 1 or 2 doses in a range of period between any two values described above. The dosage, dosing interval, and dosing method may be appropriately selected depending on the age, weight, symptom, target organ, or the like of the patient. Further, it is preferable that a therapeutic agent contains a therapeutically effective amount of effective ingredients, or an amount of effective ingredients effective for exerting a desired effect. When a malignant tumor marker significantly decreases after administration, the presence of a therapeutic effect may be acknowledged. The effective dose can be estimated from a dose-response curves obtained from in vitro or animal model testing systems. For SARS-CoV-2 N protein vaccination, the amount of N protein per vaccine injection may be in the range of about 100µg to 10mg, preferably about 500 µg to 5mg, or more preferably about 1mg to 3mg, or about 2mg. The amount of each adjuvant in the adjuvant combination comprised in a single dose vaccine injection is preferably about or equal in weight. The ratio between the ODN and STING agonist in an adjuvant combination of the invention may be 1:5 or 5:1, preferably the weight ratio is 1:2 to 2:1. Most preferably, the weight ratio is about 1:1. The amount of each adjuvant may be in the range of 100µg to 3mg. Hence, in preferred embodiments, an amount of K3 CpG of 100µg, 500 µg, 1mg, 2mg or 3mg may suitably be combined with an amount of c-di-AMP of 100µg, 500 µg, 1mg, 2mg or 3mg per vaccine injection. “Patient” or “subject” in one embodiment of the present invention includes humans and mammals excluding humans (e.g., one or more species of mice, guinea pigs, hamsters, rats, rabbits, pigs, sheep, goats, cows, horses, cats, dogs, marmosets, monkeys, and the like). The pharmaceutical composition, therapeutic agent, or prophylactic agent of the invention can be provided as a kit. In a specific embodiment, the present invention provides an agent pack or kit comprising one or more containers filled with one or more ingredients of the composition or medicament of the invention. Optionally, information indicating approval for manufacture, use, or sale for administration to a human by a government agency regulating the manufacture, use, or sale of medicaments or biological products can be appended to such a container in a stipulated form. In a specific embodiment, the pharmaceutical composition comprising an ingredient of the present invention can be administered via liposomes, microparticles, or microcapsules. In various embodiments of the present invention, it may be useful to use such a composition to achieve sustained release of the ingredient of the present invention. The formulation procedure for the therapeutic agent, prophylactic agent, or the like of the invention as a medicament or the like is known in the art. The procedure is described, for example, in the Japanese Pharmacopoeia, the United States Pharmacopeia, pharmacopeia of other countries, or the like. Thus, those skilled in the art can determine the embodiment such as the amount to be used without undue experimentation from the descriptions herein. For the purpose of clarity and a concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the disclosure includes embodiments having combinations of all or some of the features described. The content of the documents referred to herein is incorporated by reference. EXAMPLES EXAMPLE 1. SARS-CoV-2 N protein plus K3 CpG + c-di-AMP vaccination induces strong memory in both CD4+ and CD8+ T cells Vaccination with SARS-CoV-2 nucleocapsid (N) protein as antigen and the K3 CpG + c-di-AMP combination as adjuvant, induces potent CD4 and CD8 T cell memory responses. Mice were vaccinated 3 times with 2- week intervals and 30 days after last immunization they were euthanized and the immune response against SARS-CoV-2 N protein was tested. Animals were vaccinated with 3µg of SARS-CoV-2 N protein and 10 µg of K3 CpG and 10 µg of c-di-AMP. For controls, the same amount of N protein was injected with AddaVax or 10 µg of c-di-AMP alone. Thirty days after last immunization, the time at which memory immunity is established, splenocytes were stimulated in vitro with peptide pools that cover the full SARS-CoV-2 N protein. Following 6h stimulation intracellular cytokines were stained and the number of cells producing IFNγ were measured by flow cytometry (Figure 5). PMA plus ionomycin was used as a positive control for the in vitro assay. Each group 5 animals. EXAMPLE 2. SARS CoV-2 N protein plus K3 CpG + c-di-AMP vaccination induces strong Th1 and CD8 T cell memory but no Th2 memory Vaccination with SARS-CoV-2 nucleocapsid (N) protein as antigen and the K3 CpG + c-di-AMP combination as adjuvant, induces potent IFNγ- producing Th1 CD4 and CD8 T cell memory responses with no Th2 (IL-5 producing) responses. Mice were vaccinated 3 times with 2-week intervals and 30 days after last immunization they were euthanized and the immune response against SARS-CoV-2 N protein was tested. Animals were vaccinated with 3µg of SARS-CoV-2 N protein and 10 µg of K3 CpG and 10 µg of c-di-AMP. Thirty days after last immunization, the time at which memory immunity is established, splenocytes were stimulated in vitro in an ELISpot assay with peptide pools that cover the full SARS-CoV-2 N protein. IFNγ- or IL-5 producing T cells were measured by ELISpot assay. Each group 7-8 animals. Results are displayed in Table 1. Table 1. IFNγ- or IL-5 producing T cells as measured by ELISpot assay. IFN-γ SFC/1x10 ⁶ splenocytes IL-5 SFC/1x10 ⁶ splenocytes IFNγ Average IL-5 Average Unvaccinated 13.7 Unvaccinated 3.3 AddaVax 38.1 AddaVax 44.3 K3 CpG 26.7 K3 CpG 3.3 c-di-AMP 57.9 c-di-AMP 220.4 K3 CpG/c-di-AMP 768.6 K3 CpG/c-di-AMP 4.5 Materials & Methods to Examples 1 and 2 Animals. Eight to ten week-old female C57BL/6 mice were used for immunizations. To test the vaccine effect with or without anti-PD-1 treatment in tumor-bearing mice, 6-8 week-old female C57BL/6 mice were used. This study was carried out in accordance with the recommendations of the Instantie voor Dierenwelzijn (IvD), all studies were approved by the IvD (license AVD1010020209604). Specific pathogen free (SPF) C57BL/6 mice were purchased from Charles Rivers (Charles River Laboratories International, Inc. Wilmington, MA, USA) and housed in the Erasmus Dierenexperimenteel Center (EDC), Erasmus Medical Center animal facility (Rotterdam, The Netherlands), in groups of 2 to 4 mice and kept in IV cages, food and water was administered ad libitum. Proteins, peptides and adjuvants. Full length SARS-CoV-2 nucleocapsid protein (N protein; C- terminal His tagged full length protein of YP_009724397.2) was purchased from GeneTex, Inc. Irvine, CA, USA. SARS-CoV-2 nucleoprotein peptide pool JPT PepMix SARS-CoV-2 (NCAP; 10215-mer peptides with 11 amino acid overlap) was purchased from JPT (JPT Peptide Technologies GmbH, Berlin, Germany). Adjuvants used were K3 CpG ((ATCG ACTC TCGA GCGT TCTC); GeneDesign Inc., Osaka, Japan) and c-di-AMP (CAS: 54447-84-6; Yamasa Corporation, Chiba, Japan). AddaVax ^TM (InVivoGen, San Diego, USA) squalene-based commercial adjuvant was included as a control in some immunizations. SARS-CoV-2 nucleoprotein vaccinations. In order to test the SARS-CoV-2 nucleoprotein vaccine, mice were vaccinated subcutaneously in the left flank 3 times, once every two weeks. Thirty days after the last immunization mice were euthanized, and blood, spleen and left axillary and inguinal lymph nodes were collected for in vitro measurement of the memory T cell immune response. Mice were vaccinated with 100µl volume that contained 3µg of SARS-CoV-2 nucleoprotein, 10µg of K3 CpG and 10µg c-di-AMP adjuvants in sterile saline. For controls, the same amount of protein was injected in 100 µl sterile saline or 100 µl of a mix of equal volumes of sterile saline and AddaVax ^TM . Flow cytometry. Single-cell suspensions of splenocytes and lymph nodes were generated by mechanical disruption of spleens and lymph nodes and then filtering through a 40µm cell strainer (Falcon, San Jose, CA, USA). Cells were washed and counted, 2x10 ⁶ cells were used for staining. For blood staining 60µl of blood were used. After lysing erythrocytes, cells were washed and stained. In all stains cells were first pre-treated with Fc block for 10 min. For surface stains, cells were stained for 20 min on ice with different panels of antibodies. Additionally, cells were stained with PerCP- Cy 5.5 labeled Annexin V (BD Biosciences, San Jose, CA, USA) and PE labeled-tetramers of H-2Kb MHC-I loaded with OVA(257-264). After staining, cells were washed with Hank's Balanced Salt Solution (HBSS) containing 3% fetal bovine serum (FBS) and 0.02% sodium azide, and fixed with 1% paraformaldehyde (PFA). When Annexin V was used all buffers contained 2.5mM CaCl ₂ . For intracellular cytokine staining cells were stimulated with 10µg/ml SARS-CoV-2 nucleoprotein peptide pool for 6 hrs at 37°C in 5% CO ₂ in the presence of GolgiPlug ^TM (BD Biosciences) and CD107a-APC-Cy7 antibody. Cells were fixed overnight with IC Fixation Buffer at 4°C, washed with a Perm/Wash buffer (both from eBiosciences, Thermo Fisher Scientific, Waltham, MA, USA) and stained for intracellular cytokines for 45 min at 4°C. Fluorochrome conjugated antibodies for CD4 and CD8 were used. Finally, cells were washed twice with Perm/Wash buffer and fixed with 1% PFA. All samples were acquired in a Fortessa Flow Cytometer (BD Biosciences) and analyzed with FlowJo v.9.9.6 software. ELISPOT assay. The ELISPOT assays were performed according the manufacturer protocol (ImmunoSpot ^® , Cellular Technology Ltd (CTL), Shaker Heights, OH, USA). Ninety-six well ELISpot plates pre-coated overnight with anti- murine IFN-γ antibody or anti-murine IL-5 antibody according to manufacturer instructions. Plates were washed and 1x10 ⁵ cells for IFN-γ plates or 4x10 ⁵ cells for IL-5 plates were seeded in 200µl 5% FCS DMEM media per well. Cell were stimulated with media alone or SARS-CoV-2 nucleoprotein peptide pool (each peptide at 2µg/ml). As a positive control, PMA and Ionomycin were used at 20ng/ml and 500ng/ml final concentration respectively. Cells were incubated overnight at 37°C in 5% CO ₂ . The next day the wells were washed twice with PBS and twice with PBS Tween 0.05%. Anti-murine detection antibody was added and incubated at room temperature for 2 hours. After washing 3 times the plates with PBS Tween 0.05%, Streptavidin solution was added and incubated at room temperature for 30min. Plates were then washed two more times with PBS Tween 0.05% and two times with deionized H ₂ O and the developer solution was added and incubated at room temperature for 15min. The reaction was stopped by washing the plates with water, afterwards they were allowed to air-dry for at least 24 hrs before reading. Plates were read and analyzed using a CTL counter with ImmunoSpot Software (CTL, USA). EXAMPLE 3. K3 CpG plus c-di-AMP adjuvant combination when used with SARS-CoV-2 nucleocapsid protein (NC) elicits potent T cell immunity against SARS-CoV-2 NC K3 CpG plus c-di-AMP adjuvant combination when used with SARS-CoV-2 nucleocapsid protein (NC) elicits potent T cell immunity against SARS-CoV-2 NC (Figure 3). This vaccine retains its immunogenicity even when lyophilized by freeze drying (Figure 3C). Vaccination with SARS-CoV-2 NC together K3 CpG plus c-di-AMP adjuvant combination elicits strong memory Th1 immunity without memory Th2 immunity against NC protein which is elicited when c-di-AMP is used alone as an adjuvant (Figure 4A). Vaccination with SARS-CoV-2 NC together K3 CpG plus c-di-AMP adjuvant combination elicits CD4+ and CD8+ T cell memory (figure 2B). Lyophilized vaccine containing SARS-CoV-2 NC together with K3 CpG plus c-di-AMP adjuvant combination retains its activity (Figures 3 and 4). This is important as the vaccine does not require a cold chain for transport. To test protection against viral challenge with SARS-CoV-2 virus, animals were vaccinated as above with lyophilized vaccine and 28 days after the last boost animals were intranasally challenged with SARS-CoV-2 Wuhan strain (Figure 5). Immunizations. SARS-CoV-2 nucleocapsid protein (NC) (GeneTex) was used for immunization. TLR9 agonist K type of CpG ODN (K3 CpG) and STING agonist c-di-AMP adjuvants were used in vivo at 10 µg per injection in sterile saline. K3 CpG was synthesized by GeneDesign (Japan) and c-di- AMP was kindly provided by Yamasa (Japan). AddavaxTM (InVivoGen, USA) was used by mixing it with an equal volume of sterile saline. In some experiments lyophilization of vaccines was tested. Vaccines containing SARS-CoV-2 nucleocapsid protein (NC) and K3 CpG + c-di-AMP were frozen in a -80°C freezer overnight and next day they were lyophilized by a Freeze- dryer Alpha 1-2 LDplus (CHRIST) overnight. To test the immunogenicity of the vaccines, C57BL/6 mice were immunized with 100 µl of saline, each vaccine containing (3 µg of) SARS- CoV-2 nucleocapsid protein (NC) and one of Addavax (3 µg of NC in Addavax), K3 CpG + c-di-AMP, or c-di-AMP, or lyophilized and water- reconstituted vaccine, containing 3 µg of NC and 10 µg K3 CpG + 10 µg c-di- AMP. Immunization occurred in the flank on days 0, 14, and 21. On days 21 and 35, blood were obtained for ELISpot analysis. On day 56, the mice were euthanized and blood and spleens were obtained for analysis. Flow cytometry. For flow cytometry measurement of NC-specific CD4+ and CD8+ T cells, single-cell suspensions of splenocytes, tissue were mechanically disrupted and filtered through a 40 µm cell strainer (Falcon, San Jose, CA, USA). Cells were washed and counted, and 2x10 ⁶ cells were used for staining. For staining, cells were first pre-treated with anti-CD16/CD32 blocking antibodies for 10 min. For surface stains, cells were stained for 20 min on ice with surface staining antibodies. To exclude dead cells, cells were stained with PerCP-Cy 5.5-labeled Annexin V (BD Biosciences, San Jose, CA, USA) After staining, cells were washed with HBSS containing 3% FBS and 0.02% sodium azide and fixed with 1% PFA. When Annexin V was used, all buffers contained 2.5 mM of CaCl2. For intracellular cytokine staining, cells were stimulated with 2 µg/ml PepMix SARS-CoV-2 (NCAP) (JPT, see above) for 18 hrs at 37°C in 5% CO2 in the presence of GolgiPlug (BD Bioscience) and anti-CD107a-APC-Cy7 antibody. Cells were surface stained as above including anti-CD107a-APC-Cy7, fixed ON with IC Fixation Buffer at 4°C, washed with a Perm/Wash buffer (eBiosciences) and stained for intracellular cytokines for 45 min at 4°C using fluorochrome conjugated antibodies. Finally, cells were washed twice with Perm/Wash buffer and fixed with 1% PFA. All samples were acquired in a Fortessa Flow Cytometer (BD Biosciences) and analyzed with FlowJo v.9.9.6 software. ELISPOT assay. For measuring NC-specific T cells by ELISPOT assay, plates pre- coated with anti-murine IFN-γ antibody or anti-murine IL-5 antibody were used (ImmunoSpot – CTL, USA). The protocol followed was as the manufacturer recommended. Briefly, 1x10 ⁵ cells for IFN-γ plates and 4x10 ⁵ cells for IL-5 plates were seeded in 100 µl per well, and 100 µl of media, PepMix SARS-CoV-2 (NCAP) (JPT) at 2 µg/ml were used to stimulate cells. Cells were incubated overnight at 37°C in 7% CO2. The next day the wells were washed twice with PBS and twice with PBS Tween 0.05%. Anti-murine detection antibody was added and incubated at RT for 2 hrs. After washing three times the plates with PBS Tween 0.05%, Streptavidin-AP solution was added and incubated at RT for 30 min. The plates were washed two more times with PBS Tween 0.05% and two times with deionized H2O and the developer solution was added and incubated at RT for 15 min. The reaction was stopped by washing the plates with water, afterwards they were allowed to air-dry for at least 24 hours before reading. The plates were read and analyzed in a CTL counter with ImmunoSpot Software (USA). To test NC vaccine efficacy we vaccinated K18-hACE2 transgenic mice and then intranasally challenged with 10 ⁴ PFU SARS-CoV2 Wuhan strain 50µl in DMEM. Mice were vaccinated SQ in the flank with lyophilized 3µg SARS-CoV-2 NC protein plus 10µg of K3 CpG and 10µg of c-di-AMP in 100 µl of sterile saline. Controls animals were be either injected with sterile saline alone or 3µg SARS-CoV-2 N protein in AddaVax. A negative control to test specificity of vaccine protection included lyophilized 3µg full length ovalbumin protein (OVA) plus 10µg of K3 CpG and 10µg of c-di-AMP in 100 µl of sterile saline. Mice were followed up to day 14 post viral challenge for weight loss and survival.