US President Joe Biden on Friday urged people who are now eligible for COVID-19 booster shots to get the added protection a day after the Centers for Disease Control and Prevention endorsed the doses for millions of older or otherwise vulnerable Americans.

Opening a major new phase in the US vaccination drive against COVID-19, CDC Director Dr. Rochelle Walensky signed off on a series of recommendations from a panel of advisers late Thursday. Biden praised the decision and aimed to set aside any unease about the vaccination, saying that he would get his own booster soon.

The advisers said boosters should be offered to people of 65 and older, nursing home residents and those ages 50 to 64 who have risky underlying health problems. The extra dose would be given once they are at least six months past their last Pfizer shot.

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On Thursday, the panel voted against saying that people can get a booster if they are ages 18 to 64 years and are health-care workers or have another job that puts them at increased risk of being exposed to the deadly virus. But Walensky disagreed and put that recommendation back in, noting that such a move aligns with an FDA booster authorization decision earlier this week.

The Associated Press reported an administration official and said the White House did not have input in Walensky’s decision nor was given a heads-up.

On Friday, Biden said “the decision is left to the scientists and the doctors. That’s what happened here.”

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The panel had offered the option of a booster for those ages 18 to 49 who have chronic health problems and want one. But the advisers refused to go further and open boosters to otherwise healthy front-line health care workers who aren’t at risk of severe illness but want to avoid even a mild infection.

The panel voted 9 to 6 to reject that proposal. Walensky decided to disregard the advisory committee’s counsel, issuing a statement saying she had restored the recommendation.

According to experts, getting the unvaccinated their first shots remains the top priority, and the panel wrestled with whether the booster debate was distracting from that goal.

Biden stressed that the administration’s focus remained on getting people to get their first shots and that he intended to keep rolling out “vaccination requirements wherever I can.”

The US has already authorized third doses of the Pfizer and Moderna vaccines for certain people with weakened immune systems, such as cancer patients and transplant recipients. Other Americans, healthy or not, have managed to get boosters, in some cases simply by asking.

(With inputs from The Associated Press)