Emergency Use Authorization vs. Full Approval for Vaccines: There Are Differences, But Not in Safety

June 21, 2021


Jennifer Wessel, JD, MPH
Senior Policy Analyst and Data Privacy Officer

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As vaccine uptake continues to be a challenge in the United States, there have been numerous reasons for COVID-19 vaccine hesitancy. Polling shows that one reason some are hesitant is because the vaccines are not yet fully approved for commercial use by the U.S. Food and Drug Administration (FDA). In this post, we look at emergency use authorization (EUA) versus full approval of COVID-19 vaccines.

Pfizer-BioNTech and Moderna have initiated the process to receive full FDA approval for their COVID-19 vaccines, both of which are currently available in the U.S. under EUAs granted by the FDA. Some have said they would be more likely to receive the vaccines if they had full FDA approval ― but is the process for full approval all that different from approval for an EUA?

The short answer is no. The vaccine development and clinical trial processes for both are essentially the same. No vaccine can receive either designation without meeting rigorous scientific standards for safety, effectiveness, and manufacturing quality.

A biologics license application, or BLA, is what is being described as “full approval.” The standard of review is the major difference between the BLA and EUA. For an EUA, the FDA must determine that the vaccine may be effective in preventing COVID-19; that the benefits outweigh the risks; and that there are no adequate, approved, and available alternatives. The standard of review is higher for a BLA, requiring the FDA to find substantial evidence of effectiveness.

An EUA may be issued by the FDA based on interim results from clinical trials, while a BLA requires completion of clinical trials. During the EUA period, the vaccine manufacturer must meet certain requirements such as reporting adverse events, submitting periodic safety reports, maintaining records regarding the distribution, and conducting post-authorization studies to continuously monitor the safety of the vaccines.

A vaccine manufacturer receiving full approval can introduce the vaccine into interstate commerce and market it for its approved uses for an indefinite length of time. An EUA is only in effect for the duration of the public health emergency. The U.S. Department of Health and Human Services secretary must give vaccine manufacturers sufficient notice that an emergency declaration will end, allowing enough time to appropriately dispose of the vaccine.

An EUA is not a long-term alternative to obtaining full FDA approval. For this reason, manufacturers whose vaccines receive EUAs are encouraged by the FDA to continue conducting clinical trials to demonstrate the effectiveness of the vaccines and continue safety assessments to work toward full approval.