CDC advisory panel backs mix-and-match approach to Covid-19 vaccine boosters

An expert panel that advises the Centers for Disease Control and Prevention on vaccine policy voted unanimously on Thursday to recommend booster shots for people who were vaccinated with the Moderna and Johnson & Johnson Covid-19 vaccines, leaving wide leeway for people to select the booster shot of their choice.

People who were vaccinated with the Moderna product who meet eligibility criteria can get a booster shot six months or later after they completed their primary series, and all people who got the one-dose J&J vaccine should be boosted two months after the shot, the Advisory Committee on Immunization Practices stated.

CDC Director Rochelle Walensky adopted the recommendations Thursday evening.

“These recommendations are another example of our fundamental commitment to protect as many people as possible from Covid-19,” Walensky said in a statement, noting the country now has three authorized booster doses that “are all highly effective in reducing the risk of severe disease, hospitalization, and death even in the midst of the widely circulating Delta variant.”

The votes, which came after seven hours of presentations of data on the safety and efficacy of the vaccines, effectively allow people to choose the type of booster shot they want. The CDC will issue “clinical guidance” — advice to health care providers who deliver vaccine and to people getting boosters — that will attempt to steer many people toward boosting with the vaccine they were first vaccinated with, but will acknowledge that that option might not always be available or that people may prefer something else.

The ACIP votes came a day after the Food and Drug Administration announced Wednesday that it had authorized the Moderna and J&J booster doses and that heterologous boosting — using a different booster dose than the one’s primary series — would be allowed.

Heterologous boosting will give states much-needed flexibility for their vaccination rollouts, allowing teams of vaccinators to bring one type of shot to a nursing home, for example, rather than requiring them to try to match booster jabs to the vaccine brand each resident initially received.

Some members of the ACIP had hoped to use Thursday’s votes to discourage certain groups of people from certain choices, raising concerns about young men getting a third dose of mRNA vaccines — which carry a risk of myocarditis, especially in male teens — or young women getting a second dose of the J&J vaccine, which is associated with a risk of rare but devastating clotting events that seem more common in women below the age of 30.

“I can see the need for the second dose of the [J&J] product,” said committee member Pablo Sanchez, a professor of pediatrics at Ohio State University. “However, I just really wanted to say that I remain very, very, very concerned about the administration of a second dose.”

At the end of the day, the committee was persuaded that the guidance from the CDC can do that work and that its votes should be as simple and clear as possible, given the real possibility that the complexity of the booster messaging will confuse the public.

There is a different booster policy for people who are moderately or severely immunocompromised, such as people who have had a solid organ transplant or are undergoing chemotherapy for cancer. They are recommended to get a booster — a third shot — one month after completing their primary series. And if they get the Moderna vaccine, they are supposed to get a full dose. The Moderna booster authorized this week is a half-dose shot.

Now that Walensky has signed off on the ACIP’s recommendations, people who received Moderna’s vaccine are eligible for a booster shot if they are 65 years of age or older, aged 18 to 64 with health conditions that increase their risk of severe Covid, and people aged 18 to 64 who have frequent exposure to Covid because of where they live or work.  Those are the same criteria that were used last month when the Pfizer-BioNTech booster was greenlit.

Some members of the committee also made it clear they are not convinced that all the people who meet the eligibility criteria actually need to be boosted at this time. But hanging over them was the reality that Walensky had overruled the committee in September when it decided not to recommend boosters for people 18 to 64 whose jobs or living arrangements place them at higher risk of catching Covid. Having different criteria for Pfizer and Moderna vaccine recipients was clearly not on the table, especially given that the Biden administration had originally pushed for boosters for all vaccinated Americans.

“There are probably many people who are going to get a Moderna booster who don’t need it. However, given the situation that we’ve already approved a Pfizer [booster] and there are enough people who are looking for a booster, I am inclined, reluctantly, to just go ahead and recommend a similar pattern for the Moderna booster,” said James Loehr, a family physician in private practice in Ithaca, N.Y.

The sense of the inevitability of Thursday’s outcome was evident in reaction to it, which was effectively a shrug.

Norman Baylor, the CEO of Biologics Consulting and the former director of the FDA’s vaccine research office, said that the messaging opened the door to confusion for adults younger than 65. Young, healthy people don’t need boosters, he said, but people — if they drive a bus, for example — should talk to their health care provider if they think they should maybe get one.

“It is pretty straightforward for those over 65, you just do it,” Baylor said. “But for those other individuals, if you want it, it’s there.”

Paul Offit, a vaccine expert at Children’s Hospital of Philadelphia, bemoaned the message the broad criteria for booster doses for the people who got mRNA vaccines sends. “We have just sent the message … that you’re not fully immune with two doses, that it’s a three-dose vaccine,” Offit said. “I think that’s the interpretation from the general public.”

One of the ACIP members, Helen “Keipp” Talbot, wanted to send a different message. She asked if the committee could make clear that in its view, the J&J vaccine is a two-dose vaccine.

That wasn’t an option on Thursday, Doran Fink, the FDA’s liaison to ACIP, told Talbot. But his answer suggested the vaccine’s dosing regimen may be changed at some future point. “At this time,” he said, the J&J vaccine is a single dose vaccine. “This is not determinative of what the vaccination regimen might ultimately be as we accrue additional data.”

Andrew Joseph contributed reporting.