The Food and Drug Administration has scheduled a key meeting on coronavirus boosters with its outside advisers for Sept. 17 — just a few days before the Biden administration’s planned starting date for an extra-shot campaign.

The session, which will be public, could add much-needed clarity and transparency to a decision-making process that some people have criticized as confusing. But it also could fuel more controversy over an administration position some experts regard as premature.

One of the panel members is Paul A. Offit, a vaccine expert at Children’s Hospital of Philadelphia who has questioned whether boosters are needed at this time because data indicates the vaccines remain effective against severe covid-19, the disease caused by the coronavirus. Administration officials have responded that protection is waning, and it is important to make a plan to administer boosters before it is too late.

Though the purpose of the meeting is to review booster data on the Pfizer-BioNTech vaccine, it is likely to deal more broadly with hotly debated questions: What is the United States trying to achieve with vaccines? What is our obligation to other countries? Who should get boosters and when?

The panel’s recommendations are not binding. But a split between the FDA’s outside experts and agency officials could make it more difficult for the agency to approve boosters. On the other hand, if the committee concludes boosters are needed, it could strengthen the administration’s position and the agency’s hand in approving a third Pfizer-BioNTech shot and authorizing boosters by Moderna and Johnson & Johnson. The two-shot Pfizer regimen received full FDA approval last week, while the Moderna and Johnson & Johnson vaccines continue to be administered under an emergency use authorization.

Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said “a transparent, thorough and objective review of the data by the FDA is critical so that the medical community and the public continue to have confidence in the safety and effectiveness of covid-19 vaccines.”

Outside experts praised the scheduling of the meeting, saying it shows the agency is trying to stick to the normal procedures on vaccines, even amid urgency caused by the hyper-transmissible delta variant. The Biden administration announced Aug. 18 that boosters would be available the week of Sept. 20 to most people fully vaccinated eight months earlier, pending clearance from the FDA and the Centers for Disease Control and Prevention. Critics said the announcement placed too much pressure on the agencies, adding that typically the FDA and the CDC and their advisers would review data before decisions were announced.

“It’s a good sign that the FDA is trying to adhere to a regular process,” said Jason L. Schwartz, associate professor of health policy and the history of medicine at the Yale School of Public Health. But he added that the meeting could be “awkward,” with the administration receiving criticism for “a really messy sequence of events.”

As new coronavirus variants emerge and the longevity of vaccine protection remains unknown, scientists are researching how booster shots could work. (John Farrell/The Washington Post)

That argument was amplified Tuesday when news broke that two top vaccine officials said they would retire this fall. Marion Gruber, who leads the Office of Vaccines Research and Review, is scheduled to depart the FDA at the end of October. Philip Krause, Gruber’s deputy, is expected to leave the agency in November. The two career officials have decades of experience in vaccines and have helped steer the agency’s efforts through a demanding period that began 18 months ago with the pandemic. Their planned departures were first reported by BioCentury, an industry publication.

People familiar with the decisions said Gruber has been talking about retiring for some time but that Krause’s decision was more of a surprise. They said both were frustrated by what they saw as an encroachment by the White House and other agencies on the FDA’s prerogative to review data and make independent decisions. But they also said they did not know whether that was the reason for the retirements.

They also said many FDA employees are exhausted by the amount of work created by the pandemic and disheartened by the pandemic’s continued surge. The individuals spoke on the condition of anonymity because they were not authorized to discuss the situation.

Tyler Pager contributed to this report.