内容摘要：Carlos Moraes, a neurology professor at the University of Miami who wasn’t involved with the study, said research like this opens the door to more advances.

Carlos Moraes, a neurology professor at the University of Miami who wasn’t involved with the study, said research like this opens the door to more advances.

The new FDA approach is the culmination of aunder Health Secretary Robert F. Kennedy Jr.

the use of COVID shots and raising questions about the broader availability of vaccines. It was released two days ahead of the first meeting of FDA’s outside vaccine experts under Trump.but with major restrictions on who can get it — and Tuesday’s guidance mirrors those restrictions. The approval came after Trump appointees overruled FDA scientists’ earlier plans to approve the shot without restrictions.A vial of Moderna COVID-19 vaccine rests on a table at an inoculation station in Jackson, Miss., on July 19, 2022. (AP Photo/Rogelio V. Solis, File)

A vial of Moderna COVID-19 vaccine rests on a table at an inoculation station in Jackson, Miss., on July 19, 2022. (AP Photo/Rogelio V. Solis, File)Pfizer and Moderna, makers of the most commonly used COVID shots, each said they would continue to work with the agency.

For years, federal health officials have told most Americans to expect annual updates to COVID-19 vaccines, similar to the annual flu shot. Just like with flu vaccines, until now the FDA has approved updated COVID shots so long as they show as much immune protection as the previous year’s version.

But FDA’s new guidance appears to be the end of that approach, according to Prasad andPrasad and Makary criticized the U.S.’s “one-size-fits-all,” contrasting it with some European countries that recommend boosters based on age, risk and other factors.

Prasad said the FDA will ask all manufacturers to do new clinical trials in healthy people ages 50 to 64, randomly assigning them to get a vaccine or a placebo and tracking outcomes with special attention to severe disease, hospitalization or death. Companies might need to repeat that requirement for future vaccine approvals if there’s a large virus mutation rather than the past year’s incremental evolution. Companies are also free to test their vaccines for approval in younger adults and children, Prasad said, adding “this is a free country.”Since becoming the nation’s top health official in February, Kennedy has filled the FDA and other health agencies with outspoken critics of the government’s handling of COVID shots, including Makary and Prasad. Under federal procedures, the FDA releases new guidance in draft form and allows the public to comment before finalizing its plans. The publication of Tuesday’s policy in a medical journal is highly unusual and could run afoul of federal procedures, according to FDA experts.

Health experts say there are legitimate questions about how much everyone still benefits from yearly COVID vaccination or whether they should be recommended only for people at increased risk.In June, an influential panel of advisers to the CDC is set to debate which vaccines should be recommended to which groups.