BOSTON (State House News Service) – Massachusetts will “do everything we can” to make sure vaccines are available across the state if COVID-19 shots become available for young kids, Gov. Charlie Baker said Thursday.

Baker’s comments came as Cambridge-based Moderna announced it had filed with the U.S. Food and Drug Administration seeking emergency use authorization for its COVID-19 vaccine for children ages 6 months to 6 years old.

Baker said the FDA plays an important rule as “overseer and gatekeeper with respect to the efficacy and safety of vaccines generally,” and that Massachusetts will “pursue whatever the recommendations are that come out of their expert panels.”

“If there are vaccines that are available and approved by the FDA for populations under 5, we’ll certainly do everything we can to make sure that those vaccines are available to people across the Commonwealth in places like this and others, and we’ll probably work with our colleagues in the health care community and make sure that there’s a strategy to promote that, especially within the pediatric community,” he said.

Baker took questions from reporters after getting his second COVID-19 booster shot at the Melnea A. Cass Recreational Complex in Roxbury.

“I’m a four-time Pfizer-vaccinated person at this point,” he said. “I haven’t gotten COVID. It’s worked for me.”

Department of Public Health data show 253,350 people in Massachusetts had received at least two booster doses as of Wednesday. Nearly 3 million people had received at least one booster, and 5,356,389 people were considered fully vaccinated because they had completed the primary series of Moderna, Pfizer or Johnson & Johnson vaccines.

The Centers for Disease Control and Prevention recommends initial boosters for everyone 12 and older, at least two months after the J&J shot and five months after finishing a Pfizer or Moderna series.

Massachusetts residents age 50 and up are eligible for a second booster shot four months after their first booster. Baker is 65.

Additional eligibility for a second booster varies by vaccine — individuals age 18 and up can get a second Moderna booster after four months if they have certain medical conditions, and those 12 and up with the same conditions can get a second Pfizer booster after four months.

Anyone 18 and older who got the J&J vaccine for both their initial shot and booster is also eligible for a second booster — either from Moderna or Pfizer — after four months.

Saying the vaccines have been “proven worldwide to be overwhelmingly effective for keeping people from getting seriously ill or, god forbid, dying of COVID,” Baker encouraged people to use the state’s VaxFinder website to locate booster clinics.

“There are literally hundreds and hundreds of vaccine sites available in Massachusetts and they stretch from Berkshire County all the way to the Cape,” he said.

The governor said vaccines are “a big part of the reason why the pandemic is nowhere near as severe as it was 18 months ago” and that the availability of treatments like Pfizer’s antiviral Paxlovid helps keep people out of the hospital.

He called Massachusetts “a national leader in terms of the use of Paxlovid here in the commonwealth for people who get COVID and are maybe in a high-risk category.”