No need for long trials for retooled vaccines

The Food and Drug Administration said Monday that vaccine developers would not need to conduct lengthy randomized controlled trials to evaluate vaccines that have been adapted to target concerning coronavirus variants.

The recommendations, which call for small trials more like what’s required for annual flu vaccines, would greatly accelerate the review process at a time when scientists are increasingly anxious about how the variants might slow or reverse progress made against the virus.

The guidance was part of a slate of new documents the agency released Monday, including others addressing how antibody treatments and diagnostic tests might need to be retooled to respond to the virus variants. Together, they amounted to the federal government’s most detailed acknowledgment of the threat the variants pose to existing vaccines, treatments and tests for the coronavirus and come weeks after the FDA’s acting commissioner, Dr. Janet Woodcock, said the agency was developing a plan.

“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,” Woodcock said Monday.

Most of the vaccine manufacturers with authorized vaccines or candidates in late-stage trials have already announced plans to adjust their products to address the vaccine variants. The Moderna and Pfizer-BioNTech 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 already begun developing a new version of its vaccine that could be used as a booster shot against a variant that originated in South Africa, known as B.1.351, which seems to dampen the effectiveness of the existing vaccines.

A fast-spreading variant first observed in Britain has also gained a worrisome mutation that could make it harder to control with vaccines. That variant with the mutation was found in the United States last week.

The FDA acknowledged that many questions remain unanswered, such as what type of data would trigger the need for an adapted vaccine and who would make that decision. The agency also noted that scientists have not yet determined what level of antibodies in a vaccinated person’s blood would protect someone from the virus.