What's the Difference Between Emergency Use Authorization and Approval?

Woman receiving a vaccine.

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Key Takeaways

  • The FDA is working closely with manufacturers on the safety and effectiveness data it expects to see in order to consider approving a COVID-19 vaccine. 
  • The FDA plans to convene an outside advisory committee to review the data on every COVID-19 vaccine that files for authorization. 
  • Companies that get an emergency use authorization for a COVID-19 vaccine must continue their clinical trials in order to provide longer term information on safety and effectiveness. 
  • The FDA expects companies that are granted an emergency use authorization to file for a standard, non-emergency approval as well.

Less than a year after the start of the COVID-19 pandemic, the Food and Drug Administration (FDA) issued emergency use authorizations (EUAs) for three vaccine candidates. The FDA issued an EUA for the Pfizer-BioNTech vaccine on December 11, 2020, the Moderna vaccine on December 18, 2020, and the Johnson & Johnson vaccine on February 27, 2021—allowing them to become immediately available to the public.

Then, on August 23, 2021, the FDA gave full approval of the Pfizer-BioNTech COVID-19 vaccine for use in individuals ages 16 and older, making it the first COVID-19 vaccine to be granted FDA approval.

How is an EUA different than an approval? 

The EUA program was established in 2004, in the aftermath of the September 11, 2001 terror attack in the U.S., to authorize the use of an unapproved medical product or an unapproved use of an approved medical product during a declared public health emergency. COVID-19 was established as a public health emergency in the U.S. by Secretary of Health and Human Services Alex Azar on January 31, 2020. 

“When there is a declared emergency, the FDA can make a judgment that it's worth releasing something for use even without all the evidence that would fully establish its effectiveness and safety,” Joshua Sharfstein, a former principal deputy commissioner at the FDA, tells Verywell. Sharfstein is now vice dean for Public Health Practice and Community Engagement at the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland. 

EUAs were previously issued for drugs or vaccines to treat or prevent anthrax, Ebola, and Middle East respiratory syndrome (MERS), Sharfstein says.

EUA Application Requirements

A manufacturer can apply for an EUA—as opposed to a more formal approval for a biologic licensing application (BLA)—if there is no other vaccine available to prevent the condition. In addition, the FDA must decide the known and potential benefits of the vaccine outweigh the risks of receiving it.

“[For an EUA] there generally is less data than would have been available for [a BLA]," LJ Tan, chief strategy officer of the Immunization Action Coalition, an advocacy group that works on increasing immunization rates in the U.S., tells Verywell. “But that is not to say that the clinical trials are compromised in design. It's just that the EUA is issued earlier than licensure, so we will not have as much data accumulated for the trial yet.” 

According to the FDA, products submitted for an EUA must still undergo rigorous testing. In October 2020, the FDA shared industry guidance regarding what they would be looking for in terms of safety and effectiveness data for COVID-19 vaccines, including data from studies on the safety of the vaccine, plus at least two months of follow up after clinical trial completions.

According to the guidance, the FDA can grant an EUA for a vaccine if:

  • The product may reasonably prevent, diagnose, or treat such serious or life-threatening disease or condition that can be caused by SARS-CoV-2.
  • The known and potential benefits outweigh the known and potential risks.
  • There is no adequate, approved, and available alternative to the product for diagnosing, preventing, or treating the disease or condition.

The FDA expects vaccine manufacturers to include a plan for following up on the vaccine’s safety—which involves investigating any reports of deaths, hospitalizations, and other serious or clinically significant adverse events—among individuals who receive the vaccine under an EUA.

“Being open and clear about the circumstances under which the issuance of an emergency use authorization for a COVID-19 vaccine would be appropriate is critical to building public confidence and ensuring the use of COVID-19 vaccines once available,” Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research, said in a statement. “In addition to outlining our expectations for vaccine sponsors, we also hope the agency’s guidance on COVID-19 vaccines helps the public understand our science-based decision-making process that assures vaccine quality, safety and efficacy for any vaccine that is authorized or approved."

The FDA also expects manufacturers who receive an EUA to continue their clinical trials and ultimately file for a BLA. An EUA is no longer valid once a public health emergency declaration is no longer in effect, meaning full approval will be needed for the vaccine to continue to be used. 

What This Means For You

The Food and Drug Administration is permitting companies to apply for authorization for COVID-19 under a procedure called an emergency use authorization which can speed up the time it takes to get a vaccine approved.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

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2 Sources
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  1. Food and Drug Administration. Comirnaty and Pfizer-BioNTech COVID-19 vaccine. Published August 23, 2021.

  2. Food & Drug Administration. FDA in brief: FDA issues guidance on emergency use authorization for COVID-19 vaccines. Published October 6, 2020.