F.D.A. Says Pfizer Vaccine’s Benefits Outweigh Key Risks in Children 5 to 11

Federal regulators evaluated for the first time on Friday the safety and efficacy of a coronavirus vaccine for children 5 to 11, saying that the benefits of staving off Covid-19 with the Pfizer-BioNTech vaccine generally outweighed the risks of the most worrisome possible side effects in that age group.

The analysis came on the same day that the Food and Drug Administration posted data from Pfizer showing that the vaccine had a 90.7 percent efficacy rate in preventing symptomatic Covid-19 in a clinical trial of 5- to 11-year-olds.

The findings could add momentum for F.D.A. authorization of the pediatric dose on an emergency basis, perhaps as early as next week, opening up a long-awaited new phase of the nation’s vaccination campaign. The agency’s independent vaccine expert committee is set to vote Tuesday on whether to recommend authorization.

In a briefing document posted on the F.D.A. website, the agency said it had balanced the dangers of hospitalization, death or other serious consequences from Covid-19 against the risk of myocarditis. A rare condition involving inflammation of the heart muscle, myocarditis has been linked to the Pfizer-BioNTech and Moderna vaccines, especially among young men.