Emergency use authorization (EUA) allows the FDA to authorize the use of yet to be approved drugs, or unapproved uses of approved drugs, for life-threatening conditions when there are no other adequate, approved, and available options and other conditions are met. In the case of COVID-19, the FDA issued EUAs for the Pfizer, Moderna, and Johnson & Johnson vaccines, and has now issued full approval for the Pfizer and Moderna COVID-19 vaccines.

In an emergency when lives are at risk, like a pandemic, it may not be possible to have all the evidence that the FDA would usually have before approving a vaccine or drug. If there’s evidence that strongly suggests that patients have benefited from a treatment, the agency can issue an EUA to make it available. For the COVID-19 vaccines, FDA required two months of safety and efficacy data before the EUA was granted. That included clinical trials with tens of thousands of people and rigorous testing and review, and all the vaccines continue to be closely monitored. Compared to emergency use authorization, FDA approval of vaccines requires even more data on safety, manufacturing, and effectiveness over longer periods of time and includes real-world data.

Updated February 2, 2022

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