FDA leans toward authorizing Moderna booster at a half dose

Josh Wingrove and Jennifer Jacobs

The U.S. Food and Drug Administration is leaning toward authorizing half-dose booster shots of the Moderna Inc. coronavirus vaccine, satisfied that it’s effective in shoring up protection, people familiar with the matter said.

The authorization would set the stage to further widen the U.S. booster campaign after earlier authorization of the Pfizer Inc.-BioNTech SE shot. About 170 million fully vaccinated people in the U.S. received the Moderna or Pfizer shots, or 92% of the total inoculated so far.

The people spoke on the condition of anonymity, before a potential announcement. It’s not clear when an announcement will come.

In this Feb. 25, 2021, file photo, vials for the Moderna and Pfizer COVID-19 vaccines are displayed on a tray at a clinic set up by the New Hampshire National Guard in the parking lot of Exeter, N.H., High School.

Any authorization would also introduce different dosage levels for boosters. Moderna’s initial inoculations contained 100-microgram doses, and the company’s submission to regulators amounted to a push to authorize a half-dose booster, which would allow Moderna to produce more. Pfizer’s shot, for comparison, has 30-microgram initial doses and a 30-microgram booster.

Moderna declined to comment on Tuesday night. The White House and the FDA declined to comment.

The U.S. is rolling out boosters to head off what President Joe Biden’s health advisers warn are a pair of concerning trends: Hints that vaccine efficacy wanes over months, and that the two-dose regiments are weaker generally against the delta variant. The U.S. has dealt with a summer and fall wave of new cases, hospitalizations and deaths, driven by spread among unvaccinated people but increasing the exposure risk for the vaccinated.

The FDA had been seeking information about the effectiveness of a full third dose of the Moderna vaccine, but is now ready to move forward and consider the half-dose booster Moderna has proposed, the people said.

Biden, who got his Pfizer booster on Monday, has said this remains a pandemic of the unvaccinated.

Anthony Fauci, the head of the National Institute of Allergy and Infectious Diseases, has said he believes Pfizer and Moderna will eventually be considered three-dose vaccines.

As the vaccination campaign widens, sites that administer them will have to juggle different versions. In addition to Moderna potentially adding a half-dose booster, Pfizer is seeking authorization of a vaccine for children ages 5 to 11, with a 10-microgram dose – one-third the strength given to those 12 and up.

Fauci has indicated that there’ll be progress soon on booster shots for Moderna as well as Johnson & Johnson’s one-dose vaccine. “I believe it will be weeks and not months,” he told NBC’s “Meet the Press” earlier this month.