On Apr. 1, 2021, Pfizer and BioNTech announced updated topline results from analysis of 927 confirmed symptomatic cases of COVID-19 observed in their pivotal Phase 3 study through Mar. 13, 2021, showing that the Pfizer-BioNTech COVID-19 vaccine, BNT162b2, was 91.3% effective against COVID-19, measured seven days through up to six months after the second dose.

The vaccine was 100% effective against severe disease as defined by the U.S. Centers for Disease Control and Prevention (CDC), and 95.3% effective against severe COVID-19 as defined by the U.S. Food and Drug Administration (FDA). Safety data from the Phase 3 study has also been collected from more than 12,000 vaccinated participants who had a follow-up time of at least six months after the second dose, demonstrating a favorable safety and tolerability profile.