Feb. 23, 2021 -- The U.S. Food and Drug Administration said Monday that vaccines modified to target fast-changing coronavirus variants will not necessarily need to go through lengthy clinical trials to receive emergency use authorization.

Health experts have expressed concerns that clinical trials involving placebos might be outpaced by the mutating variants. The new FDA guidance says there is “an urgent need to initiate development and evaluation of vaccines against these SARSCoV-2 variants.”

The new guidance allows scientists to use small trials, similar to what’s used in development of flu vaccines, in modifying a vaccine to fight the variants. The scientists would need to submit data demonstrating the modified vaccine works and is safe.

“The FDA is committed to identifying efficient ways to modify medical products that either are in the pipeline or have been authorized for emergency use to address emerging variants,” Acting FDA Commissioner Janet Woodcock, MD, said in a statement. “By issuing these guidances, we want the American public to know that we are using every tool in our toolbox to fight this pandemic, including pivoting as the virus adapts.”

Makers of the Pfizer-BioNTech and Moderna vaccines now being used in the United States have already said they plan to modify their vaccines to be more effective against the variants.

The CDC says three coronavirus variants have been found in the United States: 1,661 cases of the B.1.1.7 variant, first identified in the U.K; 22 cases of the B.1.351 variant from South Africa; and five cases of the P.1 variant first identified in Brazil.

“An updated Covid-19 vaccine can skip the monthslong process of a randomized clinical trial that would compare it with a placebo, the agency said,” the New York Times reported. “But a tweaked vaccine will still need to go undergo some testing. In trials proposed by the F.D.A., researchers will draw blood from a relatively small group of volunteers who have been given the adapted vaccine.

“Scientists will then observe what percentage of volunteers’ samples produce an immune response to the variants in the lab, and how large that response is. The vaccines will be judged acceptable if they produce an immune response

Show Sources

FDA. Emergency Use Authorization for Vaccines to Prevent COVID-19,  “Coronavirus (COVID-19) Update: FDA Issues Policies to Guide Medical Product Developers Addressing Virus Variants”

The Centers for Disease Control: US COVID-19 Cases Caused by Variants

NYT. “The F.D.A. tells companies that vaccines adapted for new variants won’t need lengthy clinical trials.”

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