The U.S. is expanding COVID-19 boosters as it confronts the omicron surge, with the Food and Drug Administration allowing extra Pfizer shots for children as young as 12.

Boosters already are recommended for everyone 16 and older, and federal regulators on Monday decided they’re also warranted for 12- to 15-year-olds.

A panel to the Centers for Disease Control and Prevention is expected to decide later this week whether to recommend boosters for the younger teens with a final decision by Dr. Rochelle Walensky, the CDC’s director.

The FDA also said everyone 12 and older who’s eligible for a Pfizer booster can get one as early as five months after their last dose rather than six months.

FDA vaccine chief Dr. Peter Marks said even though serious illness is uncommon in younger teens, a booster will help them avoid that risk — while also helping reduce the spread of omicron or any other coronavirus mutant.

“Hopefully this will be not just a call for people to go get their booster shot,” but for the tens of millions of unvaccinated Americans to rethink that choice, Marks said. “It’s not too late to start to get vaccinated.”

The FDA based its latest booster decision largely on real-world data from Israel that found no new safety concerns when 6,300 12- to 15-year-olds got a Pfizer booster five months after their second dose.

The chief safety question for younger teens is a rare side effect called myocarditis, a type of heart inflammation seen mostly in younger men and teen boys. The vast majority of cases are mild — far milder than the heart inflammation caused by COVID-19 — and they seem to peak in older teens, the 16- and 17-year-olds.