A Food and Drug Administration advisory committee voted Wednesday to update its Covid vaccine formula ahead of the expected fall vaccination campaign, an annual step aimed at providing better protection against versions of the virus currently in circulation.
A unanimous vote by the 16-member advisory panel recommended a formula aimed at fighting the variant JN.1, or a version thereof, that dominated infections in the United States in February. In recent weeks, JN.1 has been overtaken by its descendants known as KP.2 and KP.3.
In the coming weeks, the FDA is expected to formally recommend targeting variants to vaccine manufacturers for the next round of shots in late summer or early fall. Given that new vaccine formulations may not be available until months after a variant becomes dominant, every decision involves some degree of educated guessing.
“It is becoming clear that the ideal timing for vaccine formulation decisions remains elusive,” said Jerry Weir, an official in the FDA's vaccines division.
Dr Peter Marks, who oversees the department, urged the committee to encourage manufacturers of mRNA vaccines to focus on the latest versions of the virus that are more widely distributed.
“We always say we shouldn’t chase variants, but we’re paying an incredibly high premium for mRNA vaccines to make sure we have the freshest vaccine,” he said, referring to the technology used by Moderna and Pfizer. He compared choosing a vaccine to choosing fresher milk at the grocery store.
“If this develops further in the fall, will we regret not getting closer?” Dr. Mark asked.
But Dr. Sarah Mayer, the chief vaccine official at the Centers for Disease Control and Prevention, said targeting JN.1 is more appropriate because it is at a “higher stage” in the evolution of the coronavirus and therefore likely to allow a vaccine. later this year to better address mutations in the virus.
She added that the federal government's plan for the Covid vaccination campaign assumed deployment of the JN.1 option.
“I think it’s really difficult to predict what will happen or where things will go,” she said.
The advisers' decision on Wednesday was consistent with guidance from a World Health Organization (WHO) expert committee that recommended in April that Covid vaccines switch to the JN.1 formulation.
FDA advisers reviewed data showing that the KP version of the virus accounted for about half of coronavirus cases nationwide as of late May, a sign that it will continue to spread more widely than JN.1.
Representatives from Moderna and Pfizer said the companies were prepared to produce both versions of the vaccine.
Novavax, which uses a different vaccine development technology, said it would target JN.1. Dr. Robert Walker, the company's chief medical officer, said it would be effective in neutralizing the KP strain.
According to the FDA, studies have shown that protection tends to improve the more accurately a vaccine targets dominant strains.
Federal officials on Wednesday presented an optimistic portrait of the fight against COVID-19. CDC official Natalie J. Thornburg said cases were relatively low based on data showing illness from JN.1 was no more severe than illness from previous variants.
Early data collected by the CDC shows fewer than 400 Covid deaths per week recently, down from a peak of about 2,500 per week during the winter.
Last year, the COVID-19 vaccination rate was low. Last March, CDC researchers reported that only 18% of immunocompromised adults had received the updated vaccine, providing increased protection against hospitalization. More broadly, more than 20% of adults have received a shot, according to CDC data.
The lukewarm acceptance of the updated vaccinations has extended to nursing home residents, who are most likely to suffer serious illness, hospitalization or death. About 30% of nursing home residents had their COVID shots up to date in May, down from 65% two years ago, according to data from the CDC.