On Nov. 18, 2022, Novavax announced that Health Canada had granted expanded authorization for Nuvaxovid (COVID-19 Vaccine (Recombinant protein, Adjuvanted)) (NVX-CoV2373) for active immunization to prevent coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as a homologous booster in adults aged 18 and older.

The expanded authorization was based on data from a Phase 2 trial conducted in South Africa and from the Prevent-19 Phase 3 trial conducted in the U.S. and Mexico. As part of the trials, a single booster dose of Nuvaxovid was administered to healthy adult participants approximately six to 11 months after their primary series of two doses administered three weeks apart.  The third (booster) dose produced increased immune responses to levels comparable to or exceeding those associated with protection against COVID-19 in Phase 3 clinical trials.