The panelists generally supported guidelines for the vaccines that the FDA recently issued, over
While they were divided on some of the details, the advisers said it's critical those tests are finished — especially since a vaccine offered early by definition is still experimental and may come with little evidence of how well it protects some of the people at highest risk, including older adults and minorities.
“There's only one chance to do this,” said
The daylong deliberations also were a chance for FDA to pull back the curtain on the highly technical process it uses to evaluate vaccines and try to assure the public that science, and not pressure from the Trump administration, will ultimately decide. That confidence will be critical to efforts to vaccinate millions of Americans. A recent poll by The Associated Press shows only 46% of those surveyed want to get a COVID-19 vaccine and another 29% are unsure.
“Vaccine development can be expedited. However, I want to stress that it cannot — and must not — be rushed,” Dr.
Thursday’s meeting wasn’t to evaluate any particular shots. The FDA has pledged to reconvene its advisers to publicly analyze every vaccine before the agency decides its fate. That decision time may be getting closer: One manufacturer,
Some key issues the advisers tackled:
HOW MUCH EVIDENCE IS NEEDED?
FDA is requiring manufacturers to do studies of at least 30,000 people to prove if a vaccine protects and how safe it is. Those studies must include adequate numbers of people at highest risk from COVID-19 -- older adults, minorities and anyone with other health problems.
FDA has made clear that any vaccine must be at least 50% effective. And it told companies they must track half their participants for at least two months if they get enough evidence to stop the trials early. That's about the time when major side effects crop up in other vaccines.
The panelists were divided over whether two months is enough — some wanted six.
And safety questions are growing as two of the four vaccines in final testing in the
Those halts should be reassuring that the process works, said Dr.
WOULD EMERGENCY USE DERAIL FULL ANSWERS?
Normally when a study ends because of evidence that a vaccine is working, the participants who got dummy shots are offered the real thing.
But if FDA allows emergency use of a COVID-19 vaccine and participants in the placebo group are immediately offered the real shot, researchers may not be able to get answers about a long list of remaining questions, the agency's advisers warned.
Among the concerns: It may not be clear if the first vaccines prevent people from spreading the coronavirus or just from getting seriously ill. They so far haven't been studied in pregnant women, and tests are just beginning in certain children.
And with multiple shots in the pipeline — made with different technologies that each have pros and cons — the first approved may not be the best. Yet if the public perceives one vaccine works, they may be reluctant to help test another.
Dr.
“That would be a total disaster,” agreed fellow adviser Dr.
FDA acknowledged it will be hard to ensure that full testing is finished once emergency vaccinations begin.
“Once a decision is made to unblind an ongoing placebo-controlled trial, that decision cannot be walked back and that controlled follow-up is lost forever,” Fink said. Asked how to avoid losing that crucial information, he acknowledged: “I don’t have any specific remedies to offer at this time.”
It’s an unprecedented dilemma. The FDA has previously allowed emergency use of only one vaccine, a decades-old shot that in 2005 was authorized to prevent anthrax poisoning.
WHAT ABOUT LONG-TERM SAFETY MONITORING?
Even a study of 30,000 people cannot spot a side effect that only strikes 1 in 100,000. So the government is planning extra scrutiny of every COVID-19 vaccine to hit the market.
At first there will be limited doses given to just certain high-risk people -- and those early recipients are to get text messages daily for the first week after vaccination, and then weekly out to six weeks, asking how they’re feeling.
FDA also will be checking databases of electronic health records and insurance claims, looking for any red flags.
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