Pfizer Asks F.D.A. to Authorize Its Covid-19 Vaccine for Children 5 to 11

WASHINGTON — Pfizer and BioNTech asked federal regulators on Thursday to authorize emergency use of their coronavirus vaccine for children ages 5 to 11, a move that could help protect more than 28 million people in the United States.

The companies say they are submitting data supporting the change to the Food and Drug Administration. The agency has promised to move quickly on the request and has tentatively scheduled a meeting on Oct. 26 to consider it. A ruling is expected between Halloween and Thanksgiving.

“With new cases in children in the U.S. continuing to be at a high level, this submission is an important step in our ongoing effort against Covid-19,” Pfizer said on Thursday.

Parents across the United States are anxiously awaiting the regulators’ decision, which could affect family life and the operation of schools. Clearance depends not only on the strength of the clinical trial data, but on whether the companies can prove to regulators that they are able to properly manufacture a new pediatric formulation.

Dr. Janet Woodcock, the acting F.D.A. commissioner, said last week that children might require “a different dosage or formulation from that used in an older pediatric population or adults.”

Pfizer has proposed giving children one-third of the adult dosage. That might require adding more diluent to each injection or using a different vial or syringe. The company was expected to describe the method it intended to use in its submission to the Food and Drug Administration.

Regulators will have to examine the purity and stability of mass-manufactured doses of the vaccine and determine that it matches the quality and potency of doses given to children in clinical trials. A pediatric dose will also most likely require new labeling, with special codes that would allow the Centers for Disease Control and Prevention to track specific lots in case of reports of serious side effects.

Children rarely become severely ill from Covid-19, but the Delta variant drove nearly 30,000 of them to hospitals in August. According to the American Academy of Pediatrics, nearly 5.9 million Americans younger than 18 have been infected with the coronavirus. Of the roughly 500 Americans under 18 who have died, about 125 were children ages 5 to 11.

“It really bothers me when people say kids don’t die of Covid,” said Dr. Grace Lee, an associate chief medical officer at Stanford Children’s Health who also leads a key advisory committee to the C.D.C. “They die of Covid. It’s heartbreaking.”

About one in every six Americans infected since the beginning of the pandemic was under 18 years old. But with the surge of the Delta variant, children accounted for as many as one in four infections last month, according to the American Academy of Pediatrics.

The Food and Drug Administration authorized emergency use of Pfizer’s vaccine for 12- to 15-year-olds in May. Since then, more than 8.2 million children in that age group have received at least one dose, and more than 6.7 million have been fully vaccinated.

The infection rate in the United States is currently falling, prompting hope that the Delta variant is ebbing. But public health experts worry that the onset of colder weather could result in increased transmission.

Although federal regulators are under enormous pressure to quickly review Pfizer’s application, they also face other pressing decisions. Next week, they might rule on whether people who received the Moderna and Johnson & Johnson coronavirus vaccines should receive booster shots, both potentially contentious decisions.

Public health experts have said that the agency’s review of a Pfizer pediatric dose would be closely scrutinized. According to a recent survey conducted by the Kaiser Family Foundation, roughly a third of parents of children between ages 5 and 11 said they would wait and see before allowing their children to receive such a shot.

Dr. Walt A. Orenstein, an epidemiologist at Emory University and a former director of the U.S. immunization program, said that given the competing pressures on the Food and Drug Administration to make vaccine decisions quickly but carefully, public discussion was essential.

He said many parents were wavering between fear of Covid-19 and fear of side effects of a pediatric vaccine. If they were less worried about the consequences of coronavirus infection, he said, safety would be their top priority. If they were more worried, the vaccine’s effectiveness would matter more. As with other vaccines, Dr. Orenstein said, pediatricians would play a critical role in easing parental anxiety.

Pfizer’s clinical trial for children was not intended to draw meaningful conclusions about the vaccine’s ability to prevent disease or hospitalizations. Instead, researchers looked at antibody levels, comparing them with levels in adults that had conferred high protection. Regulators are expected to compare those immune responses to vaccine efficacy data in the adult population.

The trial included 2,268 children, two-thirds of whom had received two doses of the vaccine three weeks apart. The remaining volunteers were injected with two doses of saltwater placebo. Regulators over the summer asked for the trial size to be expanded to 3,000 children.

At a virtual panel on Covid-19 last week, Norman Baylor, the former director of the Food and Drug Administration’s vaccines office, said that the number of participants in Pfizer pediatric study was noticeably small. The adult trial involved about 44,000 people.

“It does beg the question of the size, given what we have for the adults: Would one expect more for the pediatric population?” he said. “They may be thinking, ‘Well, we know the vaccine is safe, because look at how many people we had in the adults.’ But as we know, things may shift in that pediatric population.”

The Pfizer-BioNTech and Moderna vaccines have been tied to increased risks of myocarditis, or inflammation of the heart muscle; and pericarditis, inflammation of the lining around the heart, particularly in younger men. In August, the Food and Drug Administration published results from an analysis of Pfizer-BioNTech’s vaccine that used a U.S. health care claims database and found that the risk of the conditions in 16- and 17-year-old vaccinated boys could be as high as 1 in 5,000.

The cases in the database were unconfirmed, but they were considered a reasonable estimate of possible risk, the agency wrote.

A lower dose of the vaccine for children could alleviate those concerns.

Officials in a number of countries have recommended a single dose of the Pfizer-BioNTech vaccine for children ages 12 and older, which would provide partial protection from the virus, but without the potential effects occasionally observed after two doses.

Amy Schoenfeld Walker and Simone Landon contributed reporting.