The Food and Drug Administration authorized the Pfizer-BioNTech COVID-19 vaccine Friday for children ages 5 through 11, extending vaccine eligibility to roughly 28 million U.S. children and opening the final federal review needed before pediatric vaccinations can begin.

The authorization uses two 10-microgram doses given three weeks apart, one-third of the dose used for people 12 and older. In an October 29 bulletin, the FDA said immune responses in children 5 through 11 were comparable to those in people ages 16 through 25 and that the vaccine was 90.7 percent effective against symptomatic COVID-19 in the clinical trial during a period when the Delta variant was prevalent.

The authorization follows a 17-0 advisory vote

The FDA’s outside vaccine advisers met Tuesday and voted 17-0, with one abstention, that the known and potential benefits of the vaccine outweigh its known and potential risks for children in this age group. The agency’s October 26 meeting record includes the sponsor and FDA briefing documents, safety presentations, risk-benefit analyses and the voting question considered by the committee.

The decision is unusually sensitive because healthy children face a lower risk of severe COVID-19 than older adults, meaning regulators must evaluate uncommon vaccine side effects against a smaller baseline risk of hospitalization and death. The FDA’s own briefing document modeled different levels of community transmission and examined the potential benefits of preventing infections, hospitalizations and intensive-care admissions against possible vaccine-associated myocarditis.

The agency concluded that the overall benefit-risk balance favored authorization. Pfizer and BioNTech said after the advisory vote that their trial showed a favorable safety profile and strong immune responses with the lower dose. Their October 26 statement reported the 17-0 vote and said the pediatric dose was selected after evaluating safety, tolerability and immunogenicity.

The trial found 90.7 percent efficacy against symptomatic disease

Pfizer’s efficacy analysis included children who received either vaccine or placebo during the Delta wave. Three vaccinated children developed symptomatic COVID-19 compared with 16 in the placebo group, producing an estimated efficacy of 90.7 percent. The company’s October 29 announcement said the authorization is the first in the United States for a COVID-19 vaccine in children under 12.

The safety database is larger than the efficacy comparison but still far smaller than the real-world population that could become eligible. Trial participants most commonly reported injection-site pain, fatigue, headache, muscle pain, chills, fever and other short-lived reactions. No cases of myocarditis were observed in the pediatric trial, but the study was not large enough to rule out a rare event that might occur only once in tens of thousands of vaccinations.

Myocarditis and pericarditis have been observed rarely after mRNA vaccines, most often in adolescent and young adult males and particularly after a second dose. Regulators therefore modeled that risk rather than assuming its absence in younger children. One important uncertainty is whether the lower 10-microgram dose will produce a lower myocarditis rate than the 30-microgram dose used in adolescents and adults.

Children have lower individual risk, but a large cumulative burden

The pediatric debate is not driven by a claim that COVID-19 affects children as severely as older adults. It does not. The question is whether vaccination can reduce a meaningful burden of disease across a population of tens of millions of children while maintaining a favorable safety profile.

Federal officials have pointed to pediatric hospitalizations, outbreaks, missed school, household transmission and the uncommon but serious multisystem inflammatory syndrome associated with SARS-CoV-2 infection. The FDA had already begun posting pediatric review materials by October 22; its update said the October 26 public meeting would examine Pfizer-BioNTech’s request to amend the emergency authorization specifically for ages 5 through 11.

The authorization also comes as schools have returned to in-person instruction amid uneven masking rules and community vaccination rates. Children under 12 have until now depended on vaccination of adults and adolescents, masking, ventilation, testing and isolation measures rather than their own vaccine eligibility.

CDC must still recommend how the vaccine should be used

Friday’s FDA decision does not immediately put shots into pediatric arms. The Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices is scheduled to meet next week to review the evidence and vote on recommendations. CDC Director Rochelle Walensky must then issue the agency’s clinical guidance before routine vaccination of children 5 through 11 begins.

That sequence mirrors the process used for earlier vaccine authorizations: FDA determines whether a product may be used under an emergency authorization, while CDC determines how clinicians should use it in practice. The agencies can reach the same broad conclusion while addressing different questions about eligibility, timing, precautions and implementation.

The Washington Post reported Friday that federal preparations are already underway to distribute pediatric doses through pediatricians, pharmacies, community health centers and other sites if CDC recommendations follow the FDA action. The pediatric formulation will be packaged differently from adult doses to help providers distinguish the lower-strength product.

A new phase of the vaccination campaign is beginning

The practical significance of the authorization extends beyond the number of newly eligible children. Families with elementary-school-age children have spent much of 2021 making school, travel and social decisions around a vaccine boundary that stopped at age 12. That boundary is now poised to move down to age 5.

Public-health officials will still face the challenge of parental confidence. The benefit-risk calculation for a healthy 7-year-old is necessarily different from that for a 70-year-old, and parents are likely to ask detailed questions about myocarditis, dosing, long-term safety monitoring and the expected benefit against infection during a changing epidemic.

FDA officials have emphasized that the pediatric dose was not simply scaled down by body weight. It was selected through clinical testing designed to identify a dose that generates a strong immune response while limiting adverse reactions. The agency also evaluated manufacturing changes that allow the pediatric formulation to be distributed in specially labeled vials.

The authorization therefore represents a major expansion of the U.S. vaccination campaign but not the end of the pediatric review. CDC advisers will now determine how the vaccine should be recommended, surveillance systems will monitor safety as use expands, and clinicians will have to translate population-level evidence into individual conversations with parents.

For roughly 28 million children, however, the regulatory question has shifted. The FDA has determined that the vaccine may be used. If the CDC endorses it next week, the country will move from debating whether elementary-school children should have access to a COVID-19 vaccine to deciding how quickly families want to use it.