Dr. Anthony S. Fauci said the administration was optimistic that “we’re not going to see a repeat of what we saw last year,” when the Omicron variant swept through the country.
A study suggested that the updated booster shot produced higher levels of neutralizing antibodies against BA.4 and BA.5 than the first booster, the company said.
Federal officials are hoping that the encouraging results will spur more Americans to get an updated booster before a feared surge in coronavirus cases this winter.
Regulators authorized the shots for older age groups in late August, but much of the general population appears either unaware or uninterested in them.
Major data gaps, the result of decades of underinvestment in public health, have undercut the government response to the coronavirus and now to monkeypox.
Among other flaws, the public guidance during the coronavirus pandemic was “confusing and overwhelming,” the agency said.
The latest, highly contagious variant has driven up hospitalization rates and deepened worries about waning immunity among those vaccinated or boosted months ago.
Neither Pfizer’s nor Moderna’s pediatric doses have been tested against the subvariants that may soon be dominant in the U.S.
Outside experts will make their recommendations this week on how the agency should rule on applications from Pfizer and Moderna to vaccinate the nation’s youngest children.
Outside experts will meet next week to decide whether to recommend that the agency authorize the vaccine for kids 6 months and older.