FDA Authorizes First COVID-19 Vaccine for Emergency Use in the United States

Silver Spring, Maryland, USA · 11 December 2020

The United States Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) on 11 December 2020 for the COVID-19 vaccine developed by Pfizer Inc. and BioNTech SE — the first COVID-19 vaccine to be authorized for use in the United States. The authorization came less than 11 months after the SARS-CoV-2 virus was first identified and represented the culmination of an unprecedented scientific mobilization known as Operation Warp Speed.

The Authorization Decision

The EUA authorized the Pfizer-BioNTech COVID-19 vaccine for the prevention of COVID-19 in individuals 16 years of age and older. The vaccine, later marketed under the brand name Comirnaty, requires two doses administered three weeks apart.

The FDA's decision followed a thorough evaluation of the available safety and effectiveness data by the agency's Center for Biologics Evaluation and Research, as well as a public meeting of the Vaccines and Related Biological Products Advisory Committee (VRBPAC) on 10 December 2020. The advisory committee, composed of independent scientific and public health experts, voted 17 to 4 (with 1 abstention) in favor of recommending the authorization.

"The FDA's authorization for emergency use of the first COVID-19 vaccine is a significant milestone in the fight against this devastating pandemic that has affected so many families in the United States and around the world. Today's action follows an open and transparent review process that included a public advisory committee meeting and input from external scientific and public health experts."

— Dr. Stephen M. Hahn, FDA Commissioner, 11 December 2020

The Science Behind the Vaccine

The Pfizer-BioNTech vaccine was the first mRNA vaccine ever to receive authorization for use in humans. Unlike traditional vaccines, which use weakened or inactivated pathogens to trigger an immune response, mRNA vaccines work by delivering a small piece of genetic code — messenger RNA — that instructs cells to produce a harmless fragment of the virus. The immune system then recognizes this fragment as foreign and mounts a defensive response.

In this case, the mRNA encodes the spike protein of SARS-CoV-2 — the distinctive crown-like structure on the virus's surface that it uses to enter human cells. Once produced by the body's cells, the spike protein triggers both antibody production and T-cell activation, providing a multi-layered immune defense.

The Path to Authorization

Pfizer and BioNTech submitted their formal EUA request to the FDA on 20 November 2020, following the release of preliminary efficacy data from their Phase 3 trial on 9 November 2020. The companies had reported that the vaccine was more than 90% effective based on an early analysis of the first 94 confirmed cases — a result that stunned the scientific community and financial markets alike.

The final analysis, which included 170 confirmed COVID-19 cases among trial participants, showed 95% efficacy. Of the 170 cases, 162 occurred in the placebo group and only 8 in the vaccine group. The vaccine also demonstrated strong efficacy across demographic categories, including age, race, and ethnicity, and among participants with underlying health conditions.

Safety Profile

The FDA's review identified no specific safety concerns that would preclude issuance of an EUA. The most commonly reported side effects were:

• Injection site reactions: pain, redness, swelling
• Systemic reactions: fever, fatigue, headache, chills, muscle and joint pain

These side effects were generally mild to moderate and resolved within a few days. The FDA noted that the frequency and severity of side effects increased after the second dose, which is consistent with the expected immune response to a highly effective vaccine.

Global Context

The United States was not the first country to authorize the Pfizer-BioNTech vaccine. The United Kingdom had granted emergency authorization on 2 December 2020, becoming the first Western country to approve a COVID-19 vaccine. Canada followed on 9 December. The European Medicines Agency (EMA) granted conditional marketing authorization for the vaccine across the European Union on 21 December 2020.

The World Health Organization issued its own emergency use listing for the Pfizer-BioNTech vaccine on 31 December 2020, enabling its deployment through the COVAX Facility — the global initiative co-led by WHO, Gavi, and the Coalition for Epidemic Preparedness Innovations (CEPI) to ensure equitable access to COVID-19 vaccines.

Subsequent Developments

The initial EUA was just the beginning of the Pfizer-BioNTech vaccine's regulatory journey:

• 10 May 2021: The FDA expanded the EUA to include adolescents 12 through 15 years of age, following a trial showing 100% efficacy in this age group.
• 23 August 2021: The vaccine received full FDA approval for individuals 16 years and older under the brand name Comirnaty — making it the first COVID-19 vaccine to transition from emergency authorization to full licensure in the United States.
• September 2021: The FDA authorized booster doses for certain populations, citing evidence of waning immunity over time and the emergence of the Delta variant.

A Turning Point

The 11 December 2020 authorization represented more than a regulatory milestone. It was a demonstration that the global scientific enterprise — when mobilized with sufficient urgency, resources, and collaboration — could develop, test, and begin deploying a vaccine against a novel pathogen in under a year. The previous record for vaccine development was approximately four years, for mumps in the 1960s.

The Pfizer-BioNTech vaccine, alongside the Moderna vaccine authorized one week later on 18 December 2020, would go on to become the most widely administered COVID-19 vaccines in the United States and many other countries. By the end of 2021, hundreds of millions of doses had been administered worldwide, preventing an estimated millions of hospitalizations and deaths.

The authorization also validated the mRNA vaccine platform, which had been in development for over three decades but had never before been deployed at scale. The success of the Pfizer-BioNTech and Moderna vaccines opened the door to a new generation of mRNA-based vaccines and therapeutics for diseases ranging from influenza to cancer.

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Sources:

• FDA news release: FDA Authorizes Pfizer-BioNTech COVID-19 Vaccine for Emergency Use, 11 December 2020 (fda.gov)
• Pfizer press release on EUA submission, 20 November 2020 (pfizer.com)
• NIH Director's statement on COVID-19 vaccine authorization, December 2020 (nih.gov)
• WHO emergency use listing for Pfizer-BioNTech vaccine, 31 December 2020 (who.int)