WASHINGTON — Pfizer and BioNTech said on Tuesday they had applied for an emergency permit for a second booster injection of their coronavirus vaccine for adults 65 and older.
The companies’ request to the Food and Drug Administration relied heavily on data from Israel, where such shots are allowed for a somewhat broader group. Their move could spark a tedious debate among scientists about when and how to strengthen the protection of the vaccines, and for whom.
The director of Pfizer, Dr. Albert Bourla, said repeatedly over the past week that he believed an additional dose would be needed to counteract waning protection after the third dose, which is now approved for all Americans 12 years and older. “The protection you get from the third is good enough, actually pretty good for hospitalizations and deaths,” he told CBS’s “Face the Nation” on Sunday. “It’s not that good against infections.”
Earlier requests for a booster shot last fall sparked a heated public debate. Some public health experts vehemently opposed the general population last fall, only to change their minds after the Omicron variant was shown to be more adept at evading the vaccines’ shield. Scientists have continued to clash over how long the vaccines’ protection really lasts and how much benefit added injections provide.
In an interview with Business Insider on Monday, Dr. Stephen Hoge, the president of Moderna, whose vaccine is the second most widely used vaccine in the United States, is more cautious than Dr. Bourla.
“For those who are immune-compromised, those who are older adults, over the age of 50 or at least 65, we strongly recommend and encourage it,” he said. But he didn’t say how soon he thought it would be necessary. Like a number of other experts, he suggested that most people would need an annual shot to protect them from the coronavirus, just like they would from the flu.
In their justification, in part two, Pfizer and BioNTech cited recent studies from Israel, both published on preprint servers without peer review. A study, conducted in collaboration with Israel’s Ministry of Health, reviewed the health records of 1.1 million people and found that those who received a fourth dose of Pfizer’s vaccine were less likely to become infected with the virus or have a serious illness. disease than those who had. received only three doses.
But since Israel only recently began its second booster program, researchers were unable to determine whether the added protection was short-lived. Israel began offering fourth doses to health professionals in late December, then quickly expanded eligibility for those 60 and older and other vulnerable groups.
The second study, among Israeli health professionals, found that while the fourth injection of the Pfizer or Moderna vaccine increased antibody levels, it was not very effective at preventing infection. Researchers said these findings underscored the urgency of developing vaccines that target every variant circulating.
The National Institutes of Health in the United States and several vaccine manufacturers have been investigating how to update the vaccines.
Some senior government officials say a fourth injection for all older Americans might make sense now, but the general population will probably have to wait until the fall. The FDA is expected to convene a meeting of its expert advisory committee next month to discuss the issue of the fourth shots. Developments requested by Pfizer were previously reported by The Washington Post.
When asked last month if anyone would need another shot, Dr. Peter Marks, the FDA’s chief vaccine regulator, said: “Besides any surprises from new variants, perhaps it’s best to think about our booster strategy in conjunction with the flu vaccine. We’ll fall, and then get as many people as possible boosted.” Dr. Anthony S. Fauci, the White House’s chief medical adviser, has suggested that any recommendation before then would most likely target those most at risk, possibly based on underlying conditions and age.
To date, about two-thirds of Americans ages 5 and older have been fully vaccinated with two injections of a vaccine. Only about half of those eligible for booster shots have received them, but the proportion rises to two-thirds for those over 65, according to the Centers for Disease Control and Prevention.
Speaking to reporters on Tuesday, senior government officials said the government was underfunded for vaccines. Assuming regulators allow a fourth shot to people 65 and older, the administration has enough supply to manage that, officials said. But they said it couldn’t extend that effort to everyone without more funding from Congress.
The CDC has recommended that many Americans with immune deficiencies get three shots as part of their first series, followed by a fourth shot as a booster.
A study released by the agency last month showed declining protection after a booster injection of Moderna’s or Pfizer-BioNTech’s vaccine. While they didn’t break down the cases by age, underlying conditions or the presence of immune deficiencies, researchers said the findings illustrated the potential importance of a fourth injection.
The study analyzed hospital admissions and visits to emergency rooms and emergency care clinics in 10 states by people who received booster shots of the vaccine from Moderna or Pfizer-BioNTech. It found that the level of 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.
Kaiser Permanente Southern California suggested that the effectiveness of a booster dose against both symptomatic and serious illness declines within three to six months, while a fourth dose restores antibody levels to the peak levels induced by a third dose.
But other recent studies have suggested that three doses of a Covid vaccine — or even just two — are enough to protect most people from serious illness and death for a long time. As antibody levels decline, other parts of the immune system can remember and destroy the virus for many months, if not years, according to at least four studies published in leading journals in recent weeks.
“We are now starting to see diminishing returns on the number of additional doses,” E. John Wherry, the director of the Institute of Immunology at the University of Pennsylvania, said in an interview last month.
