US expected to OK mix, match booster shots
WASHINGTON – Federal regulators are expected to authorize the mixing and matching of COVID-19 booster doses this week in an effort to provide flexibility as the campaign for extra shots expands.
The upcoming announcement by the Food and Drug Administration is likely to come along with authorization for boosters of the Moderna and Johnson & Johnson shots and follows the OK for a third dose for the Pfizer vaccine for many last month.
The FDA was expected to say that using the same brand for a booster was prefered, especially for the mRNA vaccines from Pfizer and Moderna that have proved most effective against the virus. The agency was still finalizing guidance for the J&J vaccine.
Preliminary results from a government study of booster combinations found an extra dose of any type revs up levels of virus-fighting antibodies regardless of the brand people first received. But recipients of the single-dose J&J vaccination had the most dramatic response – a 76-fold and 35-fold jump in antibody levels, respectively, after a Moderna or Pfizer booster, compared to a fourfold rise after a second J&J shot.
One confusing decision is what Moderna dose to recommend in combination with other brands. Moderna has applied for its booster to be half the original dose, saying that’s plenty for people who already received two full-strength shots. But the mix-andmatch study used full-strength extra doses, and there’s no way to know if a half-dose Moderna booster would trigger as strong a reaction in J&J recipients.
Allowing mixing and matching could make the task of getting a booster simpler for Americans and allow people who may have had adverse reactions to the initial dose to try a different shot.