Do adults need a fourth dose of Covid vaccine? It’s too soon to know.

WASHINGTON — While new federal data suggests the effectiveness of booster shots wanes after about four months, the Biden administration has no plans to recommend a fourth dose of the coronavirus vaccine any time soon.

“We just don’t have enough data to know it’s a good thing to do,” said Dr. Peter Marks, chief of the Food and Drug Administration’s division that regulates vaccines, in an interview this week.

In a separate interview, Dr. Anthony S. Fauci, the White House’s chief medical adviser, said the vaccines are still a strong bulwark against serious illness, despite data from the Centers for Disease Control and Prevention showing that booster shots have some of their potency after four up to five months.

The CDC’s study, released last Friday, analyzed hospital admissions and visits to emergency rooms and emergency care clinics in 10 states by people who had had booster injections of the vaccine from Moderna or Pfizer-BioNTech. The study found that protection against hospitalization dropped from 91 percent in the two months after a third injection to 78 percent after four to five months. Effectiveness against emergency room or emergency care visits dropped from 87 percent to 66 percent.

The data came with important caveats: Researchers didn’t examine variations by age group, underlying medical conditions, or the presence of immune deficiencies. Still, they said the findings underscored the potential importance of a fourth shot.

“Should I have a fourth injection?” That’s what a lot of people ask me,” said Dr. Fauci. “The answer is if you look at where we are now, it looks like it’s good protection. Seventy-eight percent is good.”

The administration’s vaccine strategy has been under constant review since President Biden took office. What comes next, said Dr. Fauci, will depend on whether booster protection remains stable or continues to decline after four to five months — and if it continues to decline, how steeply.

“It’s not just the number, it’s the bending of the curve,” he said.

That means more uncertainty for Americans exhausted by frequent changes in vaccine recommendations — pivots largely forced by the onset of new variants. dr. Sterling Ransone, president of the American Academy of Family Physicians, said his patients continue to ask if a fourth injection will be needed and if so, when.

“It’s frustrating, isn’t it?” said Dr. Ransone, who practices in the small town of Deltaville, Virginia. “We humans want certainty and control over the situation. And this is a case where we don’t know what’s going to happen in the future. We don’t know the exact advice.”

In Bangor, Maine, Dr. James W. Jarvis, who leads the Covid response for Northern Light Health, a local health care system, tells his patients how well the vaccines work, even when boosters are needed. While they don’t provide complete protection, he said, “the most recent data really suggests these vaccines are still doing a good job.”

Updated

February 17, 2022, 5:47 PM ET

Data from Britain is similar to that from the CDC, indicating that boosters are about 75 to 85 percent effective against hospitalization four to six months after they are given. Israel has also noted that the effectiveness of the Pfizer-BioNTech vaccine declines in the months following a booster injection, according to the CDC

Israel began offering a fourth injection in late December, but only to health professionals. The CDC has recommended that people with immune deficiencies get three shots as part of their first series, followed by a fourth shot as a booster.

Biden administration officials say two-thirds of eligible adults have received a booster shot since the additional injections were approved in November. The uptake was slower in children older than 12 years, who did not qualify until early January.

The coronavirus pandemic: important things to know

dr. Marks said it could turn out the best time for an additional shot is this fall, when the spread of the coronavirus is expected to pick up again. “Besides any surprises from new variants, it might be best to think about our booster strategy in conjunction with the flu vaccine next fall, and then give as many people a boost as possible,” he said.

dr. Ransone said some of his patients would prefer that so they can get their vaccinations in one sitting.

At a session hosted by the FDA and the University of California, San Francisco last month, Dr. Marks said he hoped a third injection would provide enough protection against illness so that only one annual Covid booster would be needed. But both he and Dr. Fauci said it’s impossible to make a prediction without more data.

Earlier this month, Dr. Fauci that any recommendation would likely target those most at risk, possibly based on age and underlying conditions.

“I don’t think if you do that, you’re going to hear recommendations that would apply to everyone across the board,” he said at a White House briefing. “It will most likely take into account which subset of people have reduced protection or not against the important parameters such as hospitalization.”

Kitty Bennett contributed to research.

This post Do adults need a fourth dose of Covid vaccine? It’s too soon to know.

was original published at “https://www.nytimes.com/2022/02/17/us/fourth-dose-covid-vaccine.html”