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A Project of The Annenberg Public Policy Center
SciCheck’s COVID-19/Vaccination Project

Why are the vaccines being authorized on an emergency basis, and how is that different from full approval?


This article is available in both English and Español

The Food and Drug Administration is expediting review of the vaccines because of the public health risks of the ongoing pandemic. The authorized vaccines thus far have received an emergency use authorization, or EUA, which is typically less stringent than the full licensure, which is called a biologics license application, or BLA. However, the FDA added more rigorous requirements for a COVID-19 EUA.

Under an EUA, regulators must determine that the product “may be effective” and the “known and potential benefits outweigh the known and potential risks.” For these EUAs, the FDA required “at least one well-designed Phase 3 clinical trial that demonstrates the vaccine’s safety and efficacy in a clear and compelling manner” and wanted to see at least two months of follow-up data on half or more of the participants.

The agency said it expected vaccine companies to continue to collect data to pursue full FDA-approval.