CV2CoV, an enhanced mRNA-based SARS-CoV-2 vaccine candidate, supports higher protein expression and improved immunogenicity in rats

Abstract

AbstractMore than a year after emergence of the SARS-CoV-2 pandemic, multiple first-generation vaccines are approved and available for vaccination. Still, many challenges remain. The ongoing vaccination programs across the globe suffer from insufficient vaccine supply. The virus is adapting to the human host and novel variants are circulating that are neutralised less efficiently by antibodies raised against ancestral SARS-CoV-2 variants. Here, we describe CV2CoV, a second-generation mRNA vaccine developed for enhanced protein expression and immunogenicity. CV2CoV supports increased levels of protein expression in cell culture compared to our clinical candidate CVnCoV. Vaccination with CV2CoV induces high levels of virus neutralising antibodies with accelerated kinetics in rats. Robust antibody responses are reflected in significant cross-neutralisation of circulating SARS-CoV-2 variants of concern, i.e. B.1.1.7 and B.1.351. Together, these results underline the value of CV2CoV as next-generation SARS-CoV-2 mRNA vaccine.