Millions of Americans vaccinated against COVID-19 have the green light to get a booster dose today.

In a rare move, Centers for Disease Control and Prevention Director Rochelle Walensky late Thursday overruled her agency's advisory panel.  Walensky endorsed additional doses of the Pfizer vaccine for health care workers, teachers and other workers at risk.

The advisory committee had voted 9 to 6 against recommending boosters for people 18 to 64 who were at greater risk because of their jobs or living conditions.

Walensky’s recommendation now aligns CDC policy with the Food and Drug Administration's endorsements. Now anyone over 65, long-term care residents, people with underlying health conditions, and high-risk workers can get the vaccine. 

Walensky's decision was a boost for President Joe Biden's campaign to give a broad segment of Americans access to boosters.

The White House had come under criticism for getting ahead of the regulatory process.