Government advisers were split Thursday on whether drugmakers need to update their COVID-19 vaccines for next season, a decision overshadowed by confusion over a new Trump administration policy that may limit which Americans can get the shots.

The Food and Drug Administration’s outside experts have met annually since the launch of the first COVID-19 vaccines to discuss tweaking their recipes to stay ahead of the virus. The challenge is trying to gauge how the virus might evolve before fall vaccinations begin.

“We all want to make the perfect choice and that’s probably not possible,” FDA’s Jerry Weir told the panel of outside experts.

Some of the panelists voiced support for a switch to a newer coronavirus subtype named LP.8.1. It’s currently the dominant version and part of the same family that circulated last year — known as the JN.1 branch of the virus family tree.

“We cannot predict the future, but it seems like LP.8 would be more likely to provide us better coverage,” said Dr. Eric Rubin, a Harvard infectious disease expert and editor of the New England Journal of Medicine.

Other panelists noted that subtype is such a close relative that last year’s shots seem to offer cross-protection, at least for now but with no guarantee there wouldn’t be a different version circulating by the time a vaccination campaign ramps up in the late summer or early fall. Several advisers noted that people who want to get ahead of a summer surge like the U.S. typically experiences could seek out the current vaccines.

Trump FDA changes policy on boosters

Hanging over the meeting was an FDA announcement earlier this week that upended the prior U.S. policy of recommending annual COVID-19 boosters for all Americans ages 6 months and older. Instead, the FDA said routine vaccine approvals will be limited to seniors and younger people with underlying medical risks, pending new research for healthy adults and children.

While that change has big implications for a fall vaccination campaign, FDA leaders repeatedly sidestepped questions from advisers about whether recommending an updated formula would trigger restrictions outlined in the new policy.

“I don’t have an answer today,” said Weir. “I think a lot of this is still under discussion.”

FDA staffers also wouldn’t confirm whether the advisers would be given a chance to meet about the new standards later.

FDA vaccine chief Dr. Vinay Prasad said in opening the meeting that the agency wants “to give people a little more time to digest” the new policy and is open to feedback from its experts — although apparently not in Thursday’s public forum.

Last fall’s recipe was tailored to the so-called JN.1 family of omicron descendants. The advisory panel voted unanimously that the family still is the right overall target, but left the FDA to decide which specific subtype to choose.