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About Our Landmark Trial

The Phase 3 clinical trial was designed to determine if the Pfizer-BioNTech COVID-19 vaccine is safe and effective in preventing COVID-19 disease. This trial began July 27, 2020, and completed enrollment of 46,331 participants in January 2021. On November 18, Pfizer and BioNTech announced that, after conducting the primary efficacy analysis, their mRNA-based COVID-19 vaccine met all of the study’s primary efficacy endpoints. On December 2, 2020, the Medicines & Healthcare Products Regulatory Agency (MHRA) in the U.K. authorized the Pfizer-BioNTech COVID-19 vaccine for emergency use, marking the first Emergency Use Authorization following a worldwide Phase 3 trial of a vaccine to help fight the pandemic. Shortly after on December 11, 2020, the U.S. Food and Drug Administration (FDA) authorized the Pfizer-BioNTech COVID-19 vaccine for emergency use.

For more information on the landmark study, please see the clinical trial protocol.

Trial Enrollment graphic