Anthony S. Fauci, the White House’s chief coronavirus medical adviser, said data about booster shots for those who had received the Moderna or Johnson & Johnson coronavirus vaccines could be a few weeks away from being reviewed by the Food and Drug Administration, days after an FDA panel approved booster shots for a limited population of those who had received the Pfizer-BioNTech vaccine.

“The actual data that we’ll get [on] that third shot for the Moderna and second shot for the J & J is literally a couple to a few weeks away,” Fauci said on NBC News’s “Meet the Press” on Sunday. “We’re working on that right now to get the data to the FDA, so they can examine it and make a determination about the boosters for those people.”

Top infectious disease expert Dr. Anthony Fauci testifies before a Senate committee, July 20 in Washington. J. Scott Applewhite/Associated Press

An FDA advisory panel on Friday voted unanimously to approve a third shot of the Pfizer-BioNTech vaccine six months after the last dose for people 65 and older, for anyone at risk of severe illness, or for those whose occupations would put them at higher risk of exposure. However, the same FDA committee declined to issue a blanket approval for booster shots for Americans 16 and older. The FDA is expected to release a decision about boosters this week.

The FDA committee also did not address possible booster shots for the 81 million or so people who have received the Moderna or Johnson & Johnson vaccines. On Sunday, Fauci, director of the National Institute of Allergy and Infectious Diseases, acknowledged that those who had received vaccines other than the Pfizer-BioNTech one could be “understandably feeling left out” but sought to reassure them that data was on the way.

“We are definitely paying strong attention to both the J & J people and those who received a Moderna,” Fauci said. “They’re not being left behind by any means.”

In mid-August, President Joe Biden announced a plan to make booster shots available by Sept. 20 for vaccinated American adults eight months after the date of their second shot, citing studies that showed various decreases in the vaccines’ efficacy in protecting against infection after several months. The FDA committee’s recommendations on Friday fell far short of Biden’s announcement.

Fauci defended the administration’s messaging on booster shots but acknowledged there could be confusion.

“The president was very clear, as was the medical group when we said we are planning to do this,” Fauci said on CNN’s “State of the Union,” noting that in all official statements by administration officials, the rollout of boosters was always noted as pending and conditional on examination of the data by the FDA.

“It’s understandable how there could have been some confusion. But what was said was pretty clear,” he said.

Fauci, who is 80 and would be eligible for a booster if the FDA approves it for those over 65, added that he “certainly” plans on getting a booster. He also emphasized that the public should expect “an evolution of this process” in the next several weeks and months.

“The one thing I think people need to realize is that data are coming in, literally, on a daily and weekly basis,” Fauci said. “They’re going to continue to look at this, literally in real time. More data will be coming in on both safety for younger individuals, efficacy. . . . So the story is not over yet. I think people need to understand that. This is not the end of the story.”

Francis Collins, director of the National Institutes of Health, also said Sunday that he supported the FDA panel’s recommendation and that the evolving nature of guidance on boosters meant the scientific process was working as intended.

“In a certain way . . . this is the way it ought to be,” Collins said on CBS News’s “Face the Nation.” “Science sort of playing out in a very transparent way, looking at the data coming from multiple places, our country, other countries and trying to make the best decision for right now. That’s what they did.”

Collins said there would be a decision in the coming weeks to extend booster eligibility beyond the list that was approved by the panel Friday but declined to say whether he thought a third dose would be necessary for everyone.