TUESDAY, Feb. 23, 2021 (HealthDay News) — Long clinical trials won’t be needed to prove the effectiveness of approved COVID-19 vaccines that have been adapted to protect against variants of the new coronavirus, the U.S. Food and Drug Administration said Monday.

Instead, vaccine developers will be asked to conduct small clinical trials such as those required for annual flu vaccines, The New York Times reported.

The recommendation was among a number of new documents released Monday by the FDA, including how antibody treatments and diagnostic tests might need to be altered to respond to coronavirus variants.

Experts are growing increasingly concerned about how the variants may hinder or reverse progress against the pandemic, the Times reported.

“The emergence of the virus variants raises new concerns about the performance of these products,” acting FDA Commissioner Dr. Janet Woodcock said in a statement. “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.”

Most makers of approved COVID-19 vaccines or candidate vaccines in late-stage trials have said they plan to adapt their vaccines to tackle variants, the Times reported. The Moderna and Pfizer vaccines use mRNA technology that the companies have said can be used to alter the existing vaccines within six weeks, although testing and manufacturing would take longer.

Moderna has begun developing a new version of its vaccine that could be used as a booster shot against a virus variant that originated in South Africa, known as B.1.351, which seems to weaken the effectiveness of the existing vaccines.

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