- Advisers to the Centers for Disease Control and Prevention recommended offering booster shots of the three coronavirus vaccines available in the U.S. to tens of millions more people, voting unanimously Thursday in support of giving additional doses to certain groups previously vaccinated with Moderna's or J&J's shots.
- The recommendation followed one day after the Food and Drug Administration authorized a third dose of Moderna's vaccine for older adults and those at higher risk of COVID-19, matching the regulator's clearance for Pfizer's vaccine last month. The FDA on Wednesday also authorized a second dose of J&J's vaccine for any adult over 18 who previously received it.
- The CDC advisory committee set its recommendation guidelines broadly, however, tacitly endorsing a "mix-and-match" approach to COVID-19 booster shots. Recent results from a U.S. government-run study showed mixing booster doses could raise higher immune responses, particularly for people who first received J&J's vaccine and then later either Pfizer's or Moderna's
Regulators in the U.S. have stopped short of endorsing booster doses broadly for the general public, although some who aren't covered by current guidelines have already sought one out. Nevertheless, the FDA authorizations Wednesday and the CDC advisers recommendation Thursday should make nearly 100 million people eligible for an additional dose.
The CDC director, Rochelle Walensky, endorsed the advisers' recommendations and made them official guidance from the agency Thursday night.
The push to widen eligibility for booster doses comes as hospitalizations and deaths from COVID-19 remain significantly higher than recent lows in July, although the number of new coronavirus cases has begun to decline.
Researchers in the U.S., Israel and elsewhere have reported data suggesting waning protection, particularly against infection, from Moderna's and Pfizer's vaccines, spurring concerns among public health officials. While antibodies in people vaccinated with J&J's shot appear to be maintained, its efficacy was substantially lower in the clinical trials that supported its approval.
Those trends have led to calls for booster doses, although experts have questioned how much benefit younger and healthier adults would receive from an additional shot. Any potential gains in protection must also be weighed against known risks from the vaccines, which include a very uncommon blood-clotting condition in young women given J&J's shot and heart inflammation that's been associated in rare instances with Pfizer's and Moderna's in younger men.
The mix-and-match approach implied by the advisers' recommendations, which called for a "single COVID-19 vaccine booster dose" in eligible groups rather than specifying a brand, could ease some of those concerns.
"I think the opportunities for these heterologous boosts are priceless," said Helen Keipp Talbot, an associate medical professor at Vanderbilt University and member of the CDC's advisory committee. "It gives those who received a [J&J shot] — if you're a young woman — to receive a messenger RNA. And if you're a young man who's received [Pfizer's or Moderna's shot], maybe we switch over to the [J&J]."
The FDA's authorization includes healthy people younger than age 65 who are at risk of infection because of their jobs or other circumstances, which include healthcare workers. This raised some objection from the CDC advisers, who characterized them as the "worried well" who otherwise are not at great risk of COVID-19 complications.
"It's paying lip service to the wrong people and not protecting the people who need protecting," said Sarah Long, a pediatrics professor at Drexel University medical school and member of the panel.
CDC officials, however, said an explanation accompanying the recommendation will spell out the risks and benefits of receiving an additional dose, as well as explaining that people can still be protected by their original vaccination.
Note: This story has been updated to reflect CDC Director Rochelle Walensky signing off on the recommendations of her agency's advisers.