• The CDC on Friday approved the distribution of Pfizer and BioNTech's Covid-19 booster shots to older Americans and other vulnerable people.
• CDC Director Dr. Rochelle Walensky overruled the agency's vaccine advisory committee by expanding access to those in high-risk occupational and institutional settings.
• The move makes some 60 million Americans at the highest risk for Covid eligible for a third shot. 

The head of the Centers for Disease Control and Prevention overruled an advisory panel Friday by approving the distribution of Pfizer and BioNTech's Covid-19 booster shots to a wide array of workers across the U.S.

CDC Director Dr. Rochelle Walensky signed off on a series of recommendations from the panel, including distributing the shots to older Americans and adults with underlying medical conditions at least six months after their first series of shots. But she broke from the panel by also clearing boosters for those in high-risk occupational and institutional settings in an unusual decision that's likely to stoke protests from anti-vaccine advocates.

"As CDC Director, it is my job to recognize where our actions can have the greatest impact," Walensky said in a statement. "At CDC, we are tasked with analyzing complex, often imperfect data to make concrete recommendations that optimize health. In a pandemic, even with uncertainty, we must take actions that we anticipate will do the greatest good."

The highly unusual move aligns with the FDA's authorization of the shots earlier this week, she noted.

Roughly 60 million of the 100 million Americans who originally received the Pfizer-BioNTech Covid vaccine are now eligible for a third shot as the highly contagious delta variant continues to tear across the country, including health-care workers, teachers, grocery store employees and other essential workers.

"The majority of Americans who are fully vaccinated with the Pfizer vaccine are now able to receive the booster shot six months after they received their second shot," President Joe Biden said in addressing the nation Friday.

Hours before, the agency's Advisory Committee on Immunization Practices endorsed giving third Pfizer shots to people 65 and older and nursing home residents as well as people 18 to 64 years old with underlying medical conditions like pregnancy, HIV, cancer, diabetes, obesity or heart disease.

However, Walensky reversed a decision that was rejected by the panel Thursday evening. The panel voted 9-6 against giving booster shots to adults at a higher risk of exposure to the virus due to their workplace or institutional setting.

While the FDA and CDC reviewed data only for the Pfizer vaccine, Walensky said they will move "with the same sense of urgency" on recommendations for Moderna and Johnson & Johnson boosters as soon as that data is available. Moderna submitted its application for booster shots Sept. 1 and J&J said Wednesday that it also submitted its data showing that an extra dose of its vaccine raises protection against infection to 94%. The FDA, which vets those applications before the CDC, hasn't yet announced when it will review the data.

"My message for you is this, you still have a high degree of protection," Biden said to recipients of those two vaccines. He said regulators are "working day and night" to analyze that data.

National Institutes of Health Director Dr. Francis Collins said Thursday that a decision on third doses from Moderna and J&J could come within weeks. He added that the NIH is currently conducting a trial to determine the effects of mixing primary vaccine doses from one manufacturer with boosters made by another.

Here's what the CDC recommends:

• People 65 years and older and residents in long-term care settings should receive a booster shot of Pfizer-BioNTech's Covid vaccine at least six months after their Pfizer-BioNTech primary series;
• People 50-64 years old with underlying medical conditions should receive a booster shot from Pfizer-BioNTech at least six months after their Pfizer-BioNTech primary series;
• People 18–49 years old with underlying medical conditions may receive a booster shot of Pfizer-BioNTech's vaccine at least six months after their Pfizer-BioNTech primary series, depending on their individual benefits and risks;
• People 18-64 who are at increased risk for Covid-19 exposure and transmission because of occupational or institutional setting may receive a booster shot of Pfizer-BioNTech's vaccine at least six months after their Pfizer-BioNTech primary series, based on their individual benefits and risks.
  

"I believe we can best serve the nation's public health needs by providing booster doses for the elderly, those in long-term care facilities, people with underlying medical conditions, and for adults at high risk of disease from occupational and institutional exposures to COVID-19," she said.

Earlier Thursday, the CDC advisory panel struggled over the controversial proposal to give boosters to wide swath of the U.S. population. In breaking from the panel, Walensky has paved the way to distribute the shots to nursing home staff, people who live or work in prisons and homeless shelters, front-line health employees, unpaid caregivers, teachers and other essential workers.

"I mean, we might as well just say just give it to everybody 18 and over," committee member Dr. Pablo Sanchez said before voting against the proposal.

Dr. Leana Wen, an emergency physician and former Baltimore health commissioner, called the CDC panel's vote to reject boosters more widely a "mistake."

"Really, we are not allowing healthcare workers, many of whom got vaccinated in back in December, to get a booster? What about teachers in cramped classrooms where masks aren't required?" she tweeted, adding that CDC Director Dr. Walensky should overrule the recommendation.

At a White House Covid press briefing Friday afternoon, Walensky insisted she didn't "overrule" the committee.

"This was a scientific close call," Walensky said, noting the lengthy two-day meeting and robust debate. "In that situation, it was my call to make. If I had been in the room I would have voted yes ... after listening to all of their scientific deliberations."

She sought to reassure public confidence by encouraging people to go back and listen to the committee's discussion. "We did it publicly, we did it transparently, and we did it with some of the best scientists in the country," she added.

The CDC's final decision allows Biden to claim victory, even though he didn't get everything he wanted. The administration said it planned to start giving booster shots to people 16 and older this week. While the CDC panel's recommendation doesn't give the Biden administration everything it wanted, boosters will still be on the way for millions of Americans who originally received Pfizer's shots.

On Wednesday, the Food and Drug Administration granted emergency use authorization to administer third Pfizer shots to many Americans six months after they complete their first two doses. While the CDC's committee's recommendation isn't binding, Walensky had been expected to accept the panel's endorsement.

Walensky addressed the committee Thursday before the vote, thanking them for their work and laying out what's at stake.

"These data are not perfect, yet collectively they form a picture for us, and they are what we have in this moment to make a decision about the next stage in this pandemic," she said.

Before the vote, some committee members said they worried that widely offering boosters could interfere with efforts to get the shots to the unvaccinated or potentially reduce confidence in the vaccines' effectiveness. Others were frustrated that only Pfizer recipients would be eligible to get the shots, leaving out millions of Americans who got the Moderna and Johnson & Johnson vaccines.

The vote came at the end of a two-day meeting, where CDC advisors listened to several presentations on data to support the wide distribution of booster shots, including one from a Pfizer executive who displayed data that showed a third shot appears to be safe and boost antibody levels in recipients.

During one presentation Thursday, CDC official Dr. Sara Oliver showed observational studies from Israel, where officials began inoculating the nation's population ahead of many other countries and started offering third shots to their citizens in late July.

The Israel data has been criticized by at least one FDA official as it is based on so-called observational studies that don't adhere to the same standards as formal clinical trials. 

"We can use the experience from Israel to inform our knowledge of the safety of boosters," Oliver said, adding the country has only reported one case of a rare heart inflammation condition known as myocarditis out of nearly 3 million third doses administered.