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The Food and Drug Administration said on Monday that vaccine developers would not need to conduct long randomized controlled trials for vaccines that have been adapted to protect against affected coronavirus variants.

The recommendations, which call for smaller trials more similar to those required for annual influenza vaccines, would speed up the review process significantly at a time when scientists are increasingly concerned about how variants might slow down or reverse. progress against the virus.

The guidelines were part of a list of new documents the agency released on Monday, including others dealing with how antibody treatments and diagnostic tests may need to be rearranged to respond to variants of the virus.

Together, they represented the federal government’s most detailed recognition of the threat the variants pose to existing vaccines, treatments and tests for the coronavirus, and came weeks after Acting FDA Commissioner Dr. Janet Woodcock , said the agency was developing a plan.

“The emergence of variants of the virus raises new concerns about the performance of these products,” Dr Woodcock said in a statement Monday. “We want the American public to know that we are using every tool in our toolkit to fight this pandemic, including the pivot as the virus adapts.”

Most vaccine manufacturers with licensed vaccines or candidates in advanced testing have already announced their intention to adjust their products to accommodate vaccine variants. Moderna and Pfizer-BioNTech vaccines use mRNA technology that the companies say can be used to modify existing vaccines within six weeks, although testing and manufacturing takes longer.

Moderna has already started to develop a new version of its vaccine that could be used as a booster shot against a variant of the virus originating in South Africa known as B.1.351, which appears to weaken the effectiveness of the vaccines. existing.

A rapidly spreading coronavirus variant first seen in Britain has also acquired a disturbing mutation that could make it more difficult to control with vaccines. This variant with the mutation was found in the United States last week.

Yet the guidelines do not appear to have been written on the assumption that new vaccines were imminent or would be absolutely necessary. Despite recent indications that some variants – and in particular B.1.351 – make currently licensed vaccines less effective, vaccines still offer protection and appear to significantly reduce the severity of illness, preventing hospitalizations and death.

Asked during a Monday afternoon press briefing about how far the variants were spread before updated vaccines were needed, Dr Woodcock gave no specific criteria. “We have to anticipate that and work on it so that we have something in our back pocket before the threshold is reached,” she said.

An updated Covid-19 vaccine may skip the month-long randomized clinical trial process that would compare it to a placebo, the agency said. But a modified vaccine will still have to undergo testing. In tests proposed by the FDA, researchers will draw blood a relatively small group of volunteers who received the appropriate vaccine. Scientists will then observe the percentage of volunteer samples that produce an immune response to the variants in the lab and the magnitude of that response. Vaccines will be considered acceptable if they produce an immune response relatively close to that elicited by the original vaccines.

Dr Peter Marks, the main vaccine regulator at the FDA, told the press conference that the studies would include “a few hundred” people and last for several months.

Volunteers will also be carefully monitored for side effects. The agency said testing could be done in a single age group and then extrapolated to other age groups.

The guidelines also encouraged the use of animal studies to substantiate the case of modified vaccines, in case the immune response studies lead to ambiguous conclusions.

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

Some other vaccines are regularly updated in the same way. As the flu virus changes rapidly from year to year, vaccine developers must come up with new recipes every year.

The newly modified Covid-19 vaccines would be authorized under an amendment to the emergency authorization granted to the original vaccine, regulators said.

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