The FDA on Jan. 26 will convene a panel of outside experts to determine whether primary doses of COVID-19 vaccines should be updated to better handle variants.
"Since the initial authorizations of these vaccines, we have learned that protection wanes over time, especially as the virus rapidly mutates and new variants and subvariants emerge," the agency said in a Dec. 16 news release. "Therefore, it's important to continue discussions about the optimal composition of COVID-19 vaccines for primary and booster vaccination, as well as the optimal interval for booster vaccination."
In June, FDA advisers recommended boosters be updated to target the BA.4 and BA.5 strains, which were dominant at the time. They did not recommend adjusting the composition of shots used for primary vaccination, "because at the time the available clinical data did not support" making such a change.
News of the FDA's upcoming meeting comes as omicron subvariants BQ.1.1 and BQ.1 now make up about 3 in 4 infections in the U.S., according to the latest CDC estimates.
One other vaccine update: In the CDC's first look at how well bivalent boosters protect against severe disease, researchers found the shots are more effective at preventing hospitalization than the original vaccines, according to a pair of studies published Dec. 16. One study — based on about 15,000 hospitalizations when BA.5 was the dominant strain — found those who had received the reformulated booster had a 57 percent lower risk of hospitalization relative to unvaccinated people. Researchers also observed a 38 percent lower risk compared to those who had recently gotten doses of the original vaccine, and a 45 percent lower risk relative to those whose last dose of the original vaccine was at least 11 months earlier.
The second study looked at the efficacy of updated boosters among adults ages 65 and older. Among this population, the bivalent boosters reduced the risk of hospitalization by 84 percent compared to unvaccinated people, and by 73 percent compared to those who received at least two doses of the monovalent vaccines.
A caveat of the studies is that they were conducted before the dominance of BQ.1 and BQ.1.1. It's unclear how the newer variants affect the efficacy of the boosters.