The Food and Drug Administration on Monday authorized a Pfizer-BioNTech booster dose for children ages 12 through 15 years old.

The agency also took action to accelerate eligibility for a Pfizer-BioNTech COVID-19 booster dose to people older than 12, changing the wait time after a second shot from six months to five months. Eligibility for booster shots now stands at five months for people who received Pfizer-BioNTech for their first shots, six months after two Moderna shots, and two months after a Johnson & Johnson shot. But FDA could soon take similar action on Moderna, according to agency officials.

FDA also allows for a third primary series in younger children who are immunocompromised. Kids ages 5 through 11 years old with weakened immune systems can receive a third dose.

Children under 11 who are not immunocompromised are not yet authorized for a third dose. The FDA said those children do not require a third dose for optimal protection, but it would continue to review the data.

The moves come as an omicron surge driven by holiday celebrations and travel have driven case numbers to record highs, and children return to schools after the winter break, with some districts opting to return to online learning.

[Omicron partially evades protection from Pfizer-BioNTech vaccine]

According to Centers for Disease Control and Prevention data, the rates of COVID-19 cases in vaccinated 12- to 17-year-olds are about 56 per 100,000, a fraction of the caseload among unvaccinated kids in that age group. A delta-driven spike around back-to-school time drove the rate of cases in vaccinated teens to 68 per 100,000 before it waned, but the rate rose again. The death rate among this age group peaked at 0.04 per 100,000 in September and now stands at 0.02 per 100,000.

“The hope is that by reducing the number of 12- to 15-year-olds that get COVID-19 of any form, we will help reduce transmission of COVID-19. But the direct benefit is that it will prevent COVID-19 in its various forms,” said Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research. “Serious outcomes like hospitalization and death, while uncommon, can occur.”

CDC’s independent scientific advisers are expected to meet on the booster shots Wednesday, according to a member of the committee, the final step before children are officially eligible.

Data collected from the Ministry of Health of Israel, which began administering third shots to this age group in late November, has not revealed any new safety concerns, according to the pharmaceutical companies.

FDA reviewed this data, culled from 6,300 kids who received a booster at least 5 months following completion of the two-dose primary series. There were no cases of myocarditis or pericarditis, according to FDA. Previous data suggest the risk of myocarditis and pericarditis is less common after three doses than after two doses, perhaps because of the shorter time interval between doses, according to Marks.

“We continue to believe that broad use of boosters is essential to preserving a high level of protection against this disease and reducing the rate of hospitalizations,” Pfizer CEO Albert Bourla said.

Other experts have called for a “vaccines-plus” strategy that includes ventilation, testing and high-quality masks to suppress the surge of the highly infectious omicron variant.

“With the current wave of the omicron variant, it’s critical that we continue to take effective, life-saving preventative measures such as primary vaccination and boosters, mask-wearing and social distancing,” acting FDA Commissioner Janet Woodcock said.

FDA cited laboratory data showing that antibodies protective against omicron are ramped up by a third dose. Pfizer and BioNTech shared data last month showing that antibody levels protective against omicron are similar after three shots to antibody levels protective against the original variant after two shots. FDA also examined data from Israel, which in August implemented a five-month window for booster shots, to support the idea that booster shots were necessary earlier.

FDA pulled from prior analyses in immunocompetent children to inform its safety analysis of a third dose in immunocompromised children ages 5 through 11.

Not all of this data is publicly available. FDA did not convene a meeting of its independent advisory committee to discuss it. Some scientists on the committee echoed concerns within FDA about whether widespread administration of boosters was necessary. Those concerns were aired before omicron hit.

“We use discretion when we use our advisory groups,” Marks said. “In the setting of a wave, where for instance we saw 400,000-plus new cases over the past day or two, it makes sense to move as quickly as we possibly could.”