CDC expands Covid booster rollout, OKs mixing shots

UPDATE: Federal health officials say millions more Americans can get a Covid-19 booster and choose a different vaccine for that next shot.

Certain people who received Pfizer vaccinations months ago already are eligible for a booster.

The Centers for Disease Control and Prevention on Thursday evening said specific Moderna and Johnson & Johnson recipients should qualify, too. And in a bigger change, the agency is allowing the flexibility of “mixing and matching” that extra dose.

The Food and Drug Administration had already authorized such an expansion of the nation’s booster campaign on Wednesday, and it was also endorsed earlier Thursday by a CDC advisory panel.

ORIGINAL REPORT: WASHINGTON, DC -- Vaccine advisers to the U.S. Centers for Disease Control and Prevention voted on Thursday afternoon to recommend booster doses of both Moderna's and Johnson & Johnson Covid-19 vaccines.

The CDC's Advisory Committee for Immunization Practices accepted the U.S. Food and Drug Administration emergency use authorizations for each vaccine -- after considerable discussion about whether such broad authorization was needed for Moderna's. Members broadly agreed that people who got Johnson & Johnson's vaccine need a second vaccination, as that vaccine is less effective than Moderna's and Pfizer's in preventing infection.

It will now be up to CDC Director Dr. Rochelle Walensky to accept or modify the committee's recommendation. The CDC will also issue detailed clinical guidance spelling out what people should consider in seeking out and getting booster shots. This will include whether people should mix and match vaccines.

The FDA gave emergency use authorization Wednesday for booster doses of Moderna's and Johnson & Johnson's Janssen vaccines. The FDA also authorized a mix and match approach -- saying people could get any vaccine as a booster, regardless of which vaccine they got for the initial immunization.

The FDA'S EUA covers Moderna recipients who were vaccinated at least six months ago or longer, who are 65 or older or who are 18 or older and at high risk of severe coronavirus infection because of a medical condition or because of working or living conditions -- medical staff, for instance. That's the same as the existing EUA for Pfizer's vaccine. The EUA for the Janssen vaccine is for anyone who got that vaccine two months ago or longer.

ACIP modified its interim recommendation to use the same language to cover Moderna's and Pfizer's vaccines jointly.

When the CDC decides how and whether to adopt the ACIP recommendations, it will offer advice on how people should consider the FDA's permission to use the mix and match, formally known as heterologous, approach.

Language being considered by the CDC:

The same product that was used for the primary regimen should be used for the booster.

• If that is not available or another product is preferred, heterologous boosting with a single dose of any of the authorized Covid-19 vaccine boosters is acceptable.

Heterologous dosing may be considered for the booster dose only.

• All doses of the primary series and additional dose (if indicated for moderately to severely immunocompromised people who received 2 doses of mRNA vaccine) should utilize the same vaccine product.

Individual benefit-risk assessment may inform which booster product to use.

• Availability of booster product

• Risk profile of vaccine boosters, including rare events

CDC officials said, for instance, that young women, who have a higher risk of blood clots from the J&J Janssen vaccine, might want to consider using one of the mRNA vaccines —Pfizer's or Moderna's -- as a booster, while young men, who have a higher risk of an inflammatory heart condition known as myocarditis from an mRNA vaccine, might prefer Janssen's vaccine for a booster if needed.

At least one ACIP member expressed concern about recommending boosters for such a broad population. "I would try to mitigate the harm by having some age restriction on the otherwise worried well. Because we don't usually have vaccines because we have the worried well," said Dr. Sarah Long, a professor of pediatrics at Drexel University College of Medicine.

Long said she thought offering boosters to people who may not really need them would encourage them to get them, anyway, perhaps risking side-effects.

"I echo Dr. Long's feeling that there are probably many people who are going to get a Moderna booster who don't need it," said ACIP member Dr. James Loehr, owner of Cayuga Family Medicine in Ithaca, New York.

"However, given the situation that we've already approved the Pfizer, and there are enough people who are looking for a booster, I'm inclined, reluctantly, to just go ahead and recommend a similar pattern for the Moderna booster, with much stronger feelings in favor of the Janssen booster. "