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

Woman receiving a vaccine.

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Key Takeaways

  • The FDA expects to see safety and effectiveness data before it will approve any new vaccine.
  • Outside advisory committees review the data on each new vaccine. 
  • Companies that get an emergency use authorization must continue clinical trials. This ensures there will be longer term information on safety and effectiveness. 
  • The FDA expects companies granted an emergency use authorization will also file for standard, non-emergency approval.

The Food and Drug Administration (FDA) has issued emergency use authorizations (EUAs) for four COVID-19 vaccines since the pandemic began. These include:

The EUAs made these vaccines immediately available to the public.

On August 23, 2021, the FDA gave full approval to the Pfizer-BioNTech COVID-19 vaccine for use in people ages 16 and older. This made it the first COVID-19 vaccine to be granted FDA approval. With the approval, the vaccine is marketed under the name Comirnaty.

Under EUA, the Pfizer vaccine is also available for children and adolescents between the ages of 6 months and 15 years.

On January 31, 2022, the FDA extended full approval to the Moderna COVID-19 vaccine for use in people ages 18 and older. It is marketed under the name Spikevax. The vaccine was also granted emergency use authorization for individuals ages 6 months to 17 years.

This article looks at the difference between emergency use authorization and full FDA approval.

How is an EUA Different Than an Approval? 

The EUA program was established in 2004 after the terror attacks of September 11, 2001. The program put new rules in place for the use of certain medical products during a public health emergency. Under this program:

  • The FDA may authorize the use of an unapproved medical product
  • The FDA may authorize the use of an approved medical product for an unapproved use

COVID-19 was declared a public health emergency in the U.S. on January 31, 2020. 

Joshua Sharfstein is a former principal deputy commissioner at the FDA. “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,” he says.

Sharfstein is now vice dean for Public Health Practice and Community Engagement at the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland. 

Sharfstein says EUAs have also been used for drugs or vaccines to treat or prevent anthrax, Ebola, and Middle East respiratory syndrome (MERS).

EUA Application Requirements

Manufacturers usually have to obtain formal approval for a new vaccine. To start this process, they submit a biologic licensing application (BLA).

During a public health emergency, though, they can apply for an EUA if there is no other vaccine available. The FDA must decide if the known and potential benefits of the vaccine outweigh its risks.

“[For an EUA] there generally is less data than would have been available for [a BLA]," says LJ Tan, chief strategy officer of the Immunization Action Coalition (IAC). The IAC is an advocacy group that works to increase immunization rates in the U.S.

“But that is not to say that the clinical trials are compromised in design," he says. "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 go through rigorous testing. For the COVID-19 vaccines, the FDA told vaccine manufacturers they would need to:

  • Provide data from studies on the safety of the vaccine
  • Follow up after clinical trial completions for at least two months

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

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

The FDA also required vaccine manufacturers to have a plan for following up on the vaccine’s safety. Under these plans, manufacturers have to investigate reports of the following in people who have received their vaccine under the EUA:

  • Deaths
  • Hospitalizations
  • Other serious or significant adverse events

Peter Marks, MD, PhD, is director of the FDA’s Center for Biologics Evaluation and Research. “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,” he 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," he said.

The FDA also expects manufacturers who receive an EUA to continue their clinical trials. Ultimately, each manufacturer will need to file for a BLA.

An EUA is no longer valid once the public health emergency declaration ends. This means full approval will be needed for the vaccine to continue to be used. 

What This Means For You

During public health emergencies, the FDA lets vaccine manufacturers apply for emergency use authorization. This 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.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Comirnaty and Pfizer-BioNTech COVID-19 vaccine.

  2. Food and Drug Administration. Coronavirus (COVID-19) update: FDA authorizes Moderna and Pfizer-BioNTech COVID-19 vaccines for children down to 6 months of age.

  3. Food and Drug Administration. Coronavirus (COVID-19) update: FDA takes key action by approving second COVID-19 vaccine.

  4. Food and Drug Administration. FDA in brief: FDA issues guidance on emergency use authorization for COVID-19 vaccines.

By Fran Kritz
Fran Kritz is a freelance healthcare reporter with a focus on consumer health and health policy. She is a former staff writer for Forbes Magazine and U.S. News and World Report.