What is emergency use authorization, and why aren’t all of the COVID-19 vaccines FDA-approved?

Emergency use authorization (EUA) allows the FDA to authorize the use of yet-to-be-approved drugs, or unapproved uses of approved drugs, often in emergency situations when there are no other prevention or treatment options. The FDA issued EUAs for the Pfizer, Moderna, and Johnson & Johnson vaccines, and has now issued full approval for the Pfizer COVID-19 vaccine.

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

The Pfizer COVID-19 vaccine was the first vaccine to have the necessary data to receive EUA, and it was the first to have enough data to receive full approval (read more about FDA approval here). Moderna has also submitted an application for full approval of its COVID-19 vaccine, and the FDA is currently reviewing those data. For the time being, the Moderna and Johnson & Johnson vaccines will continue to be safely administered through emergency use authorization.

Updated October 12, 2021