explainer

What to Know About Booster Shots, Now

A person walks by a vaccine sign in Manhattan’s Union Square. Photo: Noam Galai/Getty Images

Federal agencies have signed off on making booster shots available to countless Americans who are already fully vaccinated against COVID-19, including anyone who is 65 and older. States have already begun rolling out the third doses, though there are concerns that the public will be confused about who can receive the boosters and whether or not they should following mixed messages from the Biden administration and scientists. Below is what we know about the booster rollout, who is eligible, and what’s next.

Who can get a booster shot now?

Per U.S. regulators, the following groups are now eligible for booster shots provided they were fully vaccinated with the two-dose Pfizer or Moderna COVID vaccine at least six months ago or the Johnson & Johnson vaccine at least two months ago:

  • Anyone 65 and older, who the CDC says should get a booster.
  • Long-term care facility residents aged 18 and older, who the CDC also says should now get a booster.
  • Anyone 18 to 64 years old who has an underlying medical condition that puts them at higher risk of severe COVID. (The CDC recommends members of the group who are 50 and older should get the booster, but that it is optional for those 18 to 49, who should first consult their physician about the decision.)
  • Anyone 18 to 64 years old who has “frequent institutional or occupational exposure” to COVID-19, like health-care workers and others with frontline jobs. The CDC says members of this group “may” get boosters but does not go so far as to say they “should.”

In September, CDC director Rochelle Walensky said she recognized that there was confusion regarding who should get boosted, particularly among those for whom the CDC has said the booster was optional, like people whose occupations put them at higher risk of exposure to the coronavirus. “We made it possible for people to be eligible, but they really have to identify their own individual risk and their own their own individual benefit,” she said.

Can you mix and match vaccines when getting a booster?

Yes. The FDA and CDC have both endorsed flexibility in choosing which brand of booster shot to get, including going with a different booster than what someone originally received in their primary series of the COVID vaccine.

Where will booster shots be administered?

Booster shots are expected to be available at the same places COVID vaccines are now being administered: retail pharmacies (including Walgreens, CVS, Walmart, Meijer, and Hy-Vee), doctor’s offices, and small vaccine clinics.

Most major retail pharmacies have instructed would-be booster recipients to make an appointment for the shot ahead of time.

Are the booster shots free?

Yes.

How long after being vaccinated should people wait before getting a booster?

Those with weaker immune systems are at the top of the line for boosters in order to supercharge their own antibody response. According to the federal health agencies, everyone who is eligible should wait until at least six months after their second shot to get a booster if they received an mRNA vaccine or two months after their shot if they received the Johnson & Johnson vaccine. Additionally, getting a booster shot too soon may not increase your antibodies significantly.

“Our decision today is not about who deserves a booster but who needs a booster,” Dr. Matthew Daley, senior investigator at Kaiser Permanente Colorado, said during last month’s ACIP meeting on boosters. “If you are in a group for whom a booster isn’t recommended today, the reason the booster isn’t recommended for you today is because the vaccine efficacy against serious outcomes is already high for those who have gotten the primary series.”

Are booster shots safe?

So far, side effects from an additional COVID-19 vaccine dose were similar to the primary vaccination series. A survey from Israel — the first country to officially offer a third dose — found that 88 percent of Pfizer vaccine recipients said that they felt “similar or better” in the days after their third dose than they did after the second jab. The most common side effect, like with the first two-dose regimen, was soreness at the injection site. But there’s still limited data; experts at the ACIP meeting in late September raised concerns about a third shot increasing risk of serious side effects like heart inflammation, though they’re extremely rare.

“When you look at how safe the first and the second doses of the vaccines have been, I have the inclination to think that even the third dose would continue to be quite safe,” Dr. Boghuma Titanji, infectious-disease specialist at Emory University, told NPR. “But if you’re rolling it out as a policy that then extends to millions of people, you need to show that the safety continues to hold up.”

Why did the CDC disagree with its own advisory panel on booster shots for people in high-risk occupations?

The CDC endorsed booster shots for vaccine recipients age 18 to 64 whose jobs place them at higher risk of exposure to the coronavirus, despite the CDC Advisory Committee on Immunization Practices ruling against that in late September. CDC director Rochelle Walensky ultimately disagreed with the panel’s decision, announcing that she wanted to keep the CDC’s official recommendation in line with the FDA’s earlier authorization of the occupational boosters.

The rare break with the ACIP prompted some pushback, both over concerns that the CDC is being more aggressive with boosters than the current science necessitates and that the disagreement might exacerbate confusion and hesitancy toward boosters and COVID vaccines overall.

There has also been plenty of support for the decision. The country’s top infectious-disease expert, Dr. Anthony Fauci, backed up Walensky in late September, telling Politico that he agreed with her call and adding that “Dr. Walensky made a good judgment and showed good leadership in making that decision.” Numerous other COVID experts have also come out in support of Walensky’s decision, including former Brown School of Public Health dean Ashish Jha, who told Politico that he thought the ACIP seemed to be needlessly concerned “that there were too many people that were going to become eligible at once.” On October 4, data published in the Lancet showed that after six months, the efficacy of the vaccine in preventing infection dropped from 88 percent to 47 percent, while the effectiveness in preventing death and hospitalization dropped to 90 percent.

Dr. Katherine Poehling, one of the ACIP members who voted against making boosters available for frontline workers, also indicated that she supported Walensky’s decision to overrule her recommendation. “We’re an advisory committee, and I felt like our perspectives were clearly heard. And so I felt like the process actually worked well,” Poeling told CNBC reporter Meg Tirrell, emphasizing that the official CDC recommendation allowed those workers to make their own choice as to whether or not to get a booster. In other words, she thinks Walensky incorporated their concerns into the recommendation.

Dr. Celine Gounder, an infectious-disease specialist at NYU’s Grossman School of Medicine, offered more conditional support, explaining that while available data doesn’t indicate that boosters will offer people in high-risk occupations more protection against severe illness, it does make sense to use them to prevent breakthrough infections among health-care workers, which might prevent them from being to able to work or make their workplaces less safe.

This post has been updated to reflect or include additional information.

What to Know About Booster Shots, Now