Dr. Hahn told the newspaper that a vaccine developer could apply for approval before the end of Phase 3 clinical trials, which are the largest and most rigorous, but that the agency would make “a science, medicine, data decision” and might issue emergency authorization for use for particularly vulnerable groups rather than a blanket approval.
“This is not going to be a political decision,” he said.
Dr. Hahn’s comments, published online on Sunday by The Financial Times, were not his first indication that the agency could fast-track a vaccine under the right circumstances, which would not be out of line with the agency’s standard protocols. But the interview came at the end of a particularly turbulent week for the F.D.A.
Last weekend, after President Trump criticized the agency for moving too slowly to develop vaccines and treatments and accused it of being part of the “deep state,” Dr. Hahn appeared with Mr. Trump at a news conference where they made erroneous claims that overstated the benefits of plasma treatments for Covid-19, prompting a wave of scientific disbelief and criticism.
Dr. Hahn later corrected the misleading claims. On Thursday, the Department of Health and Human Services, the parent agency of the F.D.A., terminated the contract of a public relations consultant who had advised Dr. Hahn to issue the correction, and the F.D.A.’s chief spokeswoman, who had been on the job for just 11 days, was removed from her position.
Last week, The Times reported that, on July 30, Treasury Secretary Steven Mnuchin and the White House chief of staff, Mark Meadows, told Speaker Nancy Pelosi and Senator Chuck Schumer, the Democratic leader, that a vaccine would probably be given emergency approval before the end of Phase 3 clinical trials in the United States, perhaps as early as late September.
The account was based on information from two people briefed on the discussion, who said that Mr. Meadows indicated it would most likely be the one being developed by AstraZeneca and Oxford University, which is now undergoing Phase 2 and Phase 3 trials in Britain, Brazil and South Africa. However, senior administration officials disputed the account, saying Mr. Meadows and Mr. Mnuchin were either being misrepresented or had been misunderstood.
Last week, Dr. Anthony S. Fauci, the nation’s leading expert on infectious diseases, told The Times of London that three vaccine candidates at the heart of Operation Warp Speed, the White House’s effort to speed vaccine development, were lined up for testing and that getting results by November or December was “a safe bet.” He also said that it was “conceivable that we would get an answer before that.”