Washington • A key advisory panel to the Food and Drug Administration overwhelmingly rejected recommending Pfizer booster shots for most recipients of the company’s coronavirus vaccine, instead endorsing them only for people who are 65 or older or at high risk of severe COVID-19 and received their second dose at least six months ago.
The vote — the first on boosters in the United States — was a blow to the Biden administration’s strategy to make extra shots available to most fully vaccinated adults in the United States eight months after they received a second dose. The broader rollout was to start next week.
Committee members appeared dismissive of the argument that the general population needed booster shots, saying the data from Pfizer and elsewhere still seemed to show two shots protected against severe disease or hospitalization and did not prove a third shot would stem the spread of infection. Some also criticized a lack of data that an additional injection would be safe for younger people.
“It’s unclear that everyone needs to be boosted, other than a subset of the population that clearly would be at high risk for serious disease,” said Dr. Michael Kurilla, a committee member and official at the National Institutes of Health.
But the panel’s final recommendation left some room for the White House to argue that the core of its booster strategy remained intact. Depending on how “at high risk” is defined, tens of millions of Americans could conceivably wind up eligible for additional shots of the Pfizer vaccine.
The committee of largely outside experts voted 16-2 against a Pfizer booster for people 16 and older after a tense daylong public discussion that put divisions in the agency and the administration on public display. Officials from the Centers for Disease Control and Prevention and the National Institutes of Health joined infectious disease experts and doctors in voting against additional shots for such a broad swath of the population.
Dr. Paul Offit, a committee member and the director of the Vaccine Education Center at Children’s Hospital of Philadelphia, questioned whether extra shots would do much at all to change the arc of the pandemic.
“We all agree that if we really want to impact this pandemic, we need to vaccinate the unvaccinated,” he said.
But the panel unanimously embraced a fallback position to limit additional shots to older adults and others at high risk of severe COVID illness. Then, after an informal poll pushed by a senior FDA official, committee members specified that health care workers, emergency responders and others whose jobs put them at special risk should also be eligible for the booster shots. The official — Dr. Peter Marks, who oversees the FDA’s vaccine division — said the at-risk group would also include teachers.
Biden administration aides noted that under the White House’s plan to offer booster shots eight months after the second injections, many in that same group would have been first in line because they were vaccinated earliest.
The FDA has the final word on vaccine approvals, and while it is not obliged to follow the committee’s recommendations, it typically does. The agency is likely to issue a decision by early next week.
An advisory committee of the CDC is scheduled to meet Wednesday and Thursday to discuss booster shots before that agency, which sets vaccine policy, issues recommendations on who should receive them.
In a statement about Friday’s vote, Kathrin U. Jansen, senior vice president and head of vaccine research and development at Pfizer, said, “We thank the committee for their thoughtful review of the data and will work with the FDA following today’s meeting to address the committee’s questions, as we continue to believe in the benefits of a booster dose for a broader population.”
Those who have criticized the administration’s booster strategy as overly broad or premature said the advisory committee acted as a necessary check Friday.
The meeting “put the FDA back in the driver’s seat,” said Dr. Luciana Borio, a former acting chief scientist at the agency. The expert panel, she said, “was allowed to maintain its scientific independence. It understood there were significant limitations with the data presented and that the FDA needs to review the data carefully before making a decision.”
The committee’s rejection of boosters for everyone older than 16 was the latest setback for the plan that President Joe Biden announced a month ago. The announcement prompted weeks of criticism from public health experts, who accused the administration of trying to set booster policy before FDA and CDC clearance. Regulators were forced to try to gather and analyze data at top speed, aiming to meet a deadline of next week that they had not set.
Two weeks after Biden’s announcement, leaders of the FDA and the CDC told the White House that it would be impossible to authorize booster shots for recipients of the Moderna vaccine that soon.
Then, in a remarkable public display of internal dissension, two FDA scientists co-wrote a medical journal article this week arguing that there was no credible evidence yet in support of boosters for the general population. Those officials, who are leaving the agency this fall, joined outside experts at the Friday meeting in casting doubt on whether Pfizer’s request should be approved.
Marks, their boss, also addressed the committee, noting that many well-known vaccines required booster shots. He also suggested that the committee consider the importance of not just of preventing severe disease but of curbing the spread of infection.
The panel listened to hours of contradictory presentations by officials from Pfizer, the CDC, the Israeli government and independent experts about the waning effectiveness of Pfizer and other vaccines over time.
Dr. Sara Oliver of the CDC presented data showing that vaccines continue to strongly protect against severe forms of COVID-19 in the United States, even in people 75 and older.
Jonathan Sterne, a professor of medical statistics and epidemiology in Britain, said he had analyzed 76 different studies on the vaccines’ real-world effectiveness and found that multiple factors could skew the results, including how many unvaccinated people in a study had natural immunity from prior infection. He also warned against drawing conclusions from short-term results from booster shots; data from Israel, for example, only included a follow-up period of several weeks for older adults.
Israeli experts made a different argument, telling the committee that they believed third Pfizer shots helped dampen a fourth wave of transmission as the delta variant swept the nation this summer. The Israeli government, which has relied almost entirely on the Pfizer vaccine, began offering booster shots in late July, starting with the elderly.
Dr. Sharon Alroy-Preis, Israel’s head of public health services, said the summer’s rise in the number of hospitalized patients who had been fully vaccinated with Pfizer’s vaccine was “scary.” She said 60% of severely or critically ill patients and 45% of those who died during what she called the fourth surge had received two injections of Pfizer’s vaccine.
After offering boosters to the general population, she said, Israel was now averaging about half as many severe or critically ill patients as anticipated. She said boosters not only helped curb the spread of infection but also “actually saved lives.”
Dr. William Gruber, a Pfizer senior vice president in charge of vaccine development, suggested that if the United States does not follow Israel’s lead, it could face more than 5 million more infections a year among people who received their second dose 10 months earlier, compared to those who got the second shot five months earlier.
“Israel could portend the U.S. COVID-19 future and soon,” he said.
He said Pfizer’s data showed a third shot elicited a robust antibody immune response that equaled or greatly exceeded the response after the second dose. Data also show, he argued, that breakthrough infections among vaccinated Americans are linked more to the ebbing power of the vaccine over time than to the delta variant.
But committee members and some government officials appeared deeply skeptical. Dr. Philip Krause, one of the FDA vaccine experts who wrote the medical journal review, criticized Pfizer’s presentation of data that had not been peer-reviewed or evaluated by the FDA, arguing that problems in the modeling in a study underpinning the company’s case understated the vaccine’s efficacy.
This article originally appeared in The New York Times.