As of December 2020, over 300,000 Americans have died from coronavirus disease 2019 (COVID-19).

December 11: The U.S. Food and Drug Administration (FDA) issued the first emergency use authorization for a vaccine, Pfizer-BioNTech COVID-19 Vaccine, for the prevention of COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in individuals 16 years of age and older.

December 18: the U.S. FDA U.S. issued an emergency use authorization for a second vaccine, the Moderna COVID-19 Vaccine, for use in individuals 18 years of age and older.

We now have two, count ’em two, COVID-19 vaccines that have received FDA Emergency Use Authorization (EUA). It’s not FDA approval so what is it? How is an EUA determined and what protections are included for the public? Let’s discuss based on information at and John Hopkins School of Public Health Expert Insights.

What is an emergency use authorization?

An emergency use authorization is “a mechanism to facilitate the availability and use of medical countermeasures during public health emergencies”.

These public health emergencies, like the COVID-19 pandemic we are all living through, justify the use of agents under clinical investigation because of the dire circumstances. However, there are still stringent requirements for these medical products to be given to the general population.

–> FDA emergency use authorizations are relatively new but have been critical in the response to public health emergencies. The first emergency use authorization was signed in 2009 for H1N1 pandemic (Tamiflu for infants). Since, the FDA has issued emergency use authorizations for crises like anthrax and ebola.

What was needed for an emergency use authorization?

1. Clear evidence from clinical trials that the vaccine may be effective* (at least 50%) in preventing COVID-19. Basically, show that it works in mounting immunity to fight potential infection.

The vaccines have been shown to be 95% (Pfizer-BioNTech) and 94% (Moderna) effective in clinical trials of 40,000 and 34,000+ participants, respectively.

*Vaccine effectiveness (ability of vaccine to prevent an outcomes of interest in the “real world” population outside of clinical trials) not to be confused with efficacy (% reduction of disease)

2. A determination that the known and potential benefits (eg, effectiveness) outweigh the known and potential risks (eg, side effects) based on results of clinical trials of healthy individuals.

–> Most commonly reported side effects, which typically lasted several days, were pain at the injection site, tiredness, headache, muscle pain, chills, joint pain, and fever – common side effects for vaccines.

3. Assurance of the quality and consistency of the vaccine product from one batch of vaccines to the next

Who reviewed the COVID-19 vaccine emergency use authorizations?

FDA panel: Career scientists and physicians in the area of infectious disease

Vaccines and Related Biological Products Advisory Committee: An independent group of medical advisors

*Meeting materials, presentations and discussions were livestreamed, recorded and are available for the public on

What happens next with the vaccine emergency use authorizations?

Continual safety monitoring of individuals who receive the vaccine under an EUA. Recipients of the vaccine (and the public) are required to be informed of any newly discovered risks

If the vaccine is discovered to pose a significant safety risk and doesn’t offer benefit in the real world population, FDA can retract the EUA

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