On Dec. 21, 2021, Novavax announced that the first booster doses of NVX-CoV2373, the company’s recombinant nanoparticle protein-based COVID-19 vaccine with Matrix-Mﾙ adjuvant, had been administered in an extension of the company’s PREVENT-19 pivotal Phase 3 clinical trial.

The study evaluated the safety and efficacy of a heterologous or homologous third dose of NVX-CoV2373.