A measles-vectored COVID-19 vaccine induces long-term immunity and protection from SARS-CoV-2 challenge in mice

Frantz, Phanramphoei N.; Barinov, Aleksandr; Ruffié, Claude; Combredet, Chantal; Najburg, Valérie; Teeravechyan, Samaporn; Jongkaewwattana, Anan; Prot, Matthieu; Conquet, Laurine; Montagutelli, Xavier; Fernandes, Priyanka; Strick-Marchand, Hélène; Di Santo, James; Simon-Lorière, Etienne; Gerke, Christiane; Tangy, Frédéric

In light of the expanding SARS-CoV-2 pandemic, developing efficient vaccines that can provide sufficient coverage for the world population is a global health priority. The measles virus (MV)-vectored vaccine is an attractive candidate given the measles vaccine’s extensive safety history, well-established manufacturing process, and induction of strong, long-lasting immunity. We developed an MV-based SARS-CoV-2 vaccine using either the full-length spike (S) or S2 subunit as the antigen. While the S2 antigen failed to induce neutralizing antibodies, the prefusion-stabilized, full-length S (MV-ATU2-SF-2P-dER) construct proved to be an attractive vaccine candidate, eliciting strong Th1-dominant T-cell and neutralizing antibody responses against the S antigen while minimizing reactivity to the vector itself. Neutralizing antibody titers remained high three months after homologous prime-boost immunization, and infectious virus was undetectable in all animals after challenge with a mouse-adapted SARS-CoV-2 virus.