The Food and Drug Administration’s decisions mark a big step toward expanding the U.S. booster campaign, which began with extra doses of the Pfizer vaccine last month. But before more people roll up their sleeves, the Centers for Disease Control and Prevention will consult an expert panel Thursday before finalizing official recommendations for who should get boosters and when.
The number of Americans eligible for boosters could be expanded by tens of millions with the latest moves.
The FDA specifically authorized a third Moderna shot for seniors and others at high risk from COVID-19 due to health problems, jobs, or living conditions six months after the last shot. The big change is that Moderna’s booster will be half the dose that’s used for the first two shots, based on company data showing that a smaller dose was plenty to rev up immunity again.
For J&J’s single-shot vaccine, the FDA said that all US recipients, no matter their age could get a second dose at least two months following their initial vaccination.
The rulings by the FDA differ because the vaccines are made differently, with different dosing schedules – and the J&J vaccine showing consistently lower levels of effectiveness than either of the two-shot Moderna and Pfizer vaccines.
The FDA said that it’s OK to use any brand for the booster for mixing and matching, regardless of which vaccination people got first. The interchangeability is expected to speed the booster campaign, especially in nursing homes and other settings where residents have received different shots over time.
“Being able to interchange these vaccines is a good thing — it’s like what we do with flu vaccines,” FDA’s Dr. Peter Marks told reporters Wednesday evening. “Most people don’t know what brand of flu vaccine they received.”
The agency’s mix-and-match decision was based on preliminary results from a government study of different booster combinations that showed an extra dose of any type revs up levels of virus-fighting antibodies. That study also showed recipients of the single-dose J&J vaccination had a far bigger response if they got a full-strength Moderna booster or a Pfizer booster rather than a second J&J shot. The study didn’t test the half-dose Moderna booster.