The Centers for Disease Control and Prevention officially recommended a booster dose of Pfizer and BioNTech's coronavirus vaccine for adults over 65 year old and for those over 50 with medical conditions, endorsing the advice of an expert panel that strongly supported offering an additional shot to those groups.
In an early Friday morning statement, the CDC also said younger adults with medical conditions and people aged 18 to 64 years old at higher risk of coronavirus exposure because of their job should consider getting a booster dose based on their individual risks and potential benefit.
That last recommendation, signed by CDC Director Rochelle Walensky, overruled the agency's panel, which in a 9-6 vote Thursday had opposed offering boosters to people like healthcare workers, teachers and grocery store clerks, citing weaker evidence a third shot would improve protection for those who are younger and without preexisting health conditions.
The vote against, and the CDC's unusual decision to reject it in official guidance, threatens to add new confusion over who should seek out a booster just as the U.S. government opens a new phase in its vaccination campaign.
"As CDC director, it is my job to recognize where our actions can have the greatest impact," said Walensky in a statement. "In a pandemic, even with uncertainty, we must take actions that we anticipate will do the greatest good."
The recommendations, which followed an emergency authorization issued by the Food and Drug Administration late Wednesday, open the door for potentially millions of Americans to get a booster, beginning at least six months after their first two doses of Pfizer's shot.
Rollout of the booster begins the same week the Biden administration had set out to make them broadly available, albeit in a much narrower fashion that the White House had envisioned when it announced its plans in mid-August.
The CDC committee that met Thursday, known officially as the Advisory Committee on Immunization Practices, agreed there was convincing data to recommend boosters for people over 65 after hearing presentations from Pfizer and the CDC on the vaccine's waning protection in older adults. Yet they were more divided on whether other groups are similarly vulnerable.
They also questioned how their decision would affect the tens of millions of people who previously received Moderna's and Johnson & Johnson's vaccines, people who are not included in the FDA's authorization and the CDC's guidance.
"I just don't understand how later this afternoon, we can say to people 65 and older, 'You're at risk for severe disease and death, but only half of you can protect yourself right now,'" said Sarah Long, an ACIP member and professor at Drexel University College of Medicine.
Nearly 14 million Americans over 65 years who were fully vaccinated with Pfizer's shot would be eligible for a booster dose come Sept. 27, according to a CDC presentation. Long was one of several advisers who emphasized that authorizing booster doses for only one of three approved vaccines could compromise equitable healthcare access.
"In North Dakota, when we looked at our long-term care facilities, the vast majority had a mixture of people that needed both Moderna and Pfizer," Molly Howell, a non-voting member of the committee and representative from the Association of Immunization Managers, said.
Howell echoed committee members like Long and Ohio State University professor Pablo Sanchez, who said he felt those who received J&J's single-dose vaccine were being "left out." He encouraged the committee to put out guidance for those individuals immediately.
"We understand at FDA the relative urgency here of trying to have a solution for anyone who's been vaccinated with any of the authorized or approved vaccines," said Peter Marks, the director of the FDA division that reviews vaccines. "Unfortunately, we're not in a place right now where I can give you an exact timeline."
Earlier this week, Johnson and Johnson shared long-anticipated results from a large, international trial of a two-dose regimen of its vaccine, which showed the additional shot increased protection from both moderate and more severe COVID-19. The company has not yet submitted an application for FDA authorization of its booster, but the new data could mean that's coming in the near future.
Moderna's filing for authorization, meanwhile, is currently under review.
"We will address, with the same sense of urgency, recommendations for the Moderna and J&J vaccines as soon as those data are available," CDC director Walensky said in the agency's statement Friday morning.
The FDA's authorization Wednesday had already spelled out specific groups who could receive a booster: people over 65 years old, those over 18 at risk of severe COVID-19, and those who are frequently exposed to the virus due to their work. ACIP was meant to clarify that clearance further, although the one vote against on Thursday risked new uncertainty.
To date, more than 2 million people have already received an additional shot. The FDA authorized the Pfizer vaccine as a booster to immunocompromised Americans in August, with the CDC's recommendation following shortly thereafter. Some may also have sought out a third dose on their own.
While there was agreement among the committee that boosters could be a useful tool to maintain protection for some, members also stressed that boosters would not solve the pandemic.
"I feel like we're putting lipstick on hogs," said Vanderbilt University professor Helen Keipp Talbot. She later supported making the booster shot permissible for people over 18 and allowing individuals to weigh the benefits and risks with their provider.
ACIP should not let "the perfect get in the way of the good," said committee member and private practice owner James Loehr, particularly amid a delta-driven surge in infections, hospitalizations and deaths from COVID-19 across the U.S.