Immunogenicity and efficacy of the COVID-19 candidate vector vaccine MVA-SARS-2-S in preclinical vaccination

Significance The highly attenuated vaccinia virus MVA is licensed as smallpox vaccine; a vector it component of the approved adenovirus-MVA–based prime-boost vaccine against Ebola disease. Here, we provide results from testing COVID-19 candidate MVA-SARS-2-S, poxvirus-based that proceeded to clinical evaluation. When administered by intramuscular inoculation, MVA-SARS-2-S expresses and safely delivers full-length SARS-CoV-2 S protein, inducing balanced SARS-CoV-2–specific cellular humoral immunity, protective efficacy in vaccinated mice. Substantial experience has been gained with vectors using homologous heterologous applications, including immunization children immunocompromised individuals. Thus, represents an important resource for developing further optimized vaccines.