On Jun. 7, 2021, Moderna announced that it had submitted for authorization of its COVID-19 vaccine in adolescents with Health Canada.

The vaccine efficacy in the nearly 2,500 adolescents who received the Moderna COVID-19 vaccine was observed to be 100% when using the same case definition as in the Phase 3 COVE study in adults. In addition, a vaccine efficacy of 93% in seronegative participants was observed starting 14 days after the first dose using the secondary Centers for Disease Control and Prevention (CDC) case definition of COVID-19, which tested for milder disease.