Research on Covid Booster Shots is Conflicting

Research published this week indicated the booster shots were not now necessary for everyone, a view that prevailed at the agency’s advisory committee meeting.,

Advertisement

Continue reading the main story

The F.D.A.’s day of lively debate revealed key new questions about the evidence on boosters.

Mark Turney, 66, a kidney transplant patient, received a booster shot of the Pfizer-BioNTech Covid-19 vaccine in Hartford, Conn., last month. Scientists are debating the need for a third shot.
Mark Turney, 66, a kidney transplant patient, received a booster shot of the Pfizer-BioNTech Covid-19 vaccine in Hartford, Conn., last month. Scientists are debating the need for a third shot.Credit…Joseph Prezioso/Agence France-Presse — Getty Images
  • Sept. 17, 2021Updated 5:44 p.m. ET

Advisers to the Food and Drug Administration on Friday questioned a key assertion by researchers in Israel and by the drug company Pfizer that protection from its coronavirus vaccines wanes over time not just against infection, but against severe illness and hospitalization.

The advisers met to evaluate Pfizer’s application for approval of booster vaccine doses for all Americans over age 16. The committee voted to recommend booster shots for recipients of the Pfizer-BioNTech vaccine who are 65 or older or are at high risk of severe Covid-19, at least six months after the second shot.

Among the details that surfaced during the lively debate: Israel defines anyone with an accelerated respiratory rate and an oxygen level of below 94 percent as being severely ill. By contrast, the Centers for Disease Control and Prevention considers people who are sick enough to be hospitalized as having severe disease, according to Dr. Sara Oliver, a C.D.C. scientist who presented data on the trajectory of the pandemic in the United States.

The discrepancy might explain why the two countries have reported vastly different outcomes in people who are fully immunized. Israeli researchers said they have seen large numbers of hospitalized patients who had received two doses months earlier.

But in the United States, the C.D.C. has reported that vaccinated patients make up about 2 percent of people hospitalized for Covid-19.

Other advisers noted that antibodies prompted by the shots are expected to wane over time, as Pfizer and the Israeli scientists noted. But studies so far — including from Pfizer — have indicated that immune cells that prevent severe illness remain stable. One study published this week showed steady levels of immune cells seven months after the second dose.

The opposing views were laid out in three important pieces of research published this week.

On Monday, in the journal The Lancet, an international team of scientists analyzed dozens of studies and concluded that boosters are not yet needed by the general population, and that the world would be better served by using vaccine doses to protect the billions of people who remain unvaccinated.

On Wednesday, scientists at the F.D.A. posted an assessment online hinting that they, too, are unconvinced that there’s enough evidence that boosters are needed.

“Overall, data indicate that currently U.S.-licensed or authorized Covid-19 vaccines still afford protection against severe Covid-19 disease and death in the United States,” according to their executive summary.

But some F.D.A. leaders have publicly endorsed booster shots. “The need for an additional dose at six months to provide longer-term protection should not come as a surprise, as it’s likely necessary for the generation of a mature for immune response,” Dr. Peter Marks, one of the agency’s top officials, said in the meeting on Friday.

White House officials have said they are particularly worried by data from Israel, where officials have said that vaccinated people are seeing waning immune responses and higher rates of infection.

Alarmed by the rise in cases, Israeli officials have offered third doses of the vaccine to everyone older than 12. Researchers from Israel published early results from that rollout on Wednesday in the New England Journal of Medicine — but few outside scientists found the study convincing.

The team collected data on the effects of booster shots from the health records of more than 1.1 million people over age 60. At least 12 days after the booster, rates of infection were elevenfold lower — and rates of severe disease nearly twentyfold lower — in those who received a booster compared with those who had received only two doses, the researchers found.

The results are unsurprising, experts said, and do not indicate long-term benefit.

Image

Dr. Celine Gounder, an infectious disease expert at Bellevue Hospital in New York and a former member of the Biden-Harris Covid-19 advisory council.Credit…Amr Alfiky/The New York Times

“We have known for some time that the vaccines elicit less robust immune responses in the elderly,” said Dr. Celine Gounder, an infectious disease specialist at Bellevue Hospital Center and a former adviser to the Biden administration. “Recommending additional doses of vaccine for the elderly isn’t controversial.”

Vaccination remains powerfully protective against severe illness and hospitalization in the vast majority of people in all of the studies published so far, experts said. But the vaccines do seem less potent against infections in people of all ages, particularly those exposed to the highly contagious Delta variant.

The cumulative data so far suggest that only older adults will need boosters, a view underscored by the F.D.A.’s advisory committee vote on Friday. But White House officials have said that they do not want to wait for hospitalizations to begin rising — if they ever do — among the vaccinated before taking action.

The Biden administration has said that booster doses could be rolled out quickly, should the F.D.A. and the Centers for Disease Control and Prevention deem them necessary. An advisory committee to the C.D.C. is scheduled to meet next week to lay out more details about who should receive booster shots.

British scientists have recommended giving third doses to adults over 50 and other medically vulnerable people. France, Germany, Denmark and Spain are also considering boosters for older adults or have already begun administering them. Israel is already contemplating fourth doses for its population.

But recent history leaves many experts leery of adding the United States to the list.

Dr. Luciana Borio, a former acting chief scientist at the F.D.A., criticized the Biden administration for announcing a plan for boosters before federal scientists could review the evidence.

The Trump administration pressured scientists at the F.D.A. to authorize hydroxychloroquine and convalescent plasma, for example, without enough evidence to support either treatment. “It seems to me that there’s been a process foul in how we go about making those decisions,” Dr. Borio said.

“We need an F.D.A. that has people making these decisions and retaining that ability to make those decisions independently and based on science alone. If this changes, we all lose.”

Leave a Reply