Epstein–Barr virus (EBV) infection is causally linked to multiple sclerosis and is strongly associated with a broad spectrum of malignancies and immune-mediated diseases in both immunocompetent and immunocompromised individuals. Despite its substantial global disease burden, no licensed EBV vaccine is available, reflecting the virus’s complex lifecycle, extensive host interactions, and potent immune evasion strategies. Although phase II clinical trials have shown that neutralizing antibodies can prevent symptomatic infectious mononucleosis following primary infection, they do not prevent asymptomatic EBV infection. Accordingly, current vaccine candidates in advanced clinical development largely focus on viral glycoproteins to induce neutralizing antibody responses. However, effective immune control of EBV in healthy individuals requires coordinated humoral and cellular immunity directed against antigens expressed during both latent and lytic phases, with CD8⁺ T cells playing a central role in controlling viral latency.
Here, we developed and evaluated two EBV vaccine platforms, a protein subunit vaccine and an mRNA-based vaccine, each encoding a polyepitope construct comprising 20 CD8⁺ T-cell epitopes derived from latent and lytic antigens, in combination with the major EBV glycoprotein gp350. Comparative immunogenicity analyses demonstrated that the mRNA vaccine elicited significantly stronger and broader immune responses than the subunit protein formulation. The mRNA-based vaccine induced higher frequencies of polyfunctional gp350-specific CD4⁺ and CD8⁺ T cells, robust EBV-specific CD8⁺ T-cell responses, and potent gp350-specific plasma cell and memory B-cell responses. In addition, vaccination generated high titers of gp350-specific IgG, IgM, and IgA antibodies capable of neutralizing clinical EBV isolates. Collectively, these data indicate that an mRNA-based EBV vaccine designed to elicit coordinated humoral and cellular immunity against multiple viral antigens may enhance protection against primary EBV infection, limit latent viral persistence, and reduce the risk of EBV-associated disease.