With vaccine approval process set to change, FDA advisers leave wiggle room in annual Covid-19 shot recommendations

Yahoo

23-05-2025

A group of experts who advise the US Food and Drug Administration on its vaccine decisions voted unanimously Thursday to make a broad recommendation about which lineage of the coronavirus should be included in this year's Covid-19 vaccines, giving the agency latitude to keep the current shots or update its formulas to more closely match circulating viruses.
Several of the committee members asked at Thursday's meeting about the FDA's new vaccine approval framework. Some expressed concern that changing the strain targeted in this year's vaccine might decrease access to the shots in the fall, since the updated version would require new FDA approval.
Capt. Sarah Meyer, a pediatrician who directs the Immunization Safety Office at the US Centers for Disease Control and Prevention, posed it as the first question of the meeting.
'I did have a question on how the new regulatory framework put forward this week might affect aspects related to selecting the strain. For example, if a different strain was selected for this season, would that require additional clinical trials, etc.?' she asked.
'I think that's a little off-topic,' said Dr. Jerry Weir, a longtime FDA staffer who is director of the Division of Viral Products within the agency's Center for Biologics Evaluation and Research. 'I think for today, we focus mainly on what we think in this committee should be in the vaccine, and then the rest of it, we'll work on that later.'
Under the new framework, the agency says, it will accept the same kind of study data it has been using to approve annual flu shots and updated Covid-19 vaccines, but only for certain groups: those 65 and older and people with underlying medical conditions that put them at higher risk of severe illness.
In order to approve Covid-19 vaccines for healthy younger adults and children, however, the agency now wants to see placebo-controlled clinical trials, which take longer and are expensive to run. Even if vaccine manufacturers choose to run those studies, it's unlikely that the research could be conducted in time for them to have shots ready for everyone 6 months and older by the fall.
'Is there a possibility that if we choose a different vaccine, [there are] actually going to be different regulatory measures that are taken that would delay the vaccine getting to the market?' asked committee member Dr. Stanley Perlman, a microbiologist and immunologist at the University of Iowa.
FDA representatives attending the meeting had no firm answers about whether changing the targeted coronavirus strain might put the shots out of reach for some groups this fall.
'I think that the goal today is to figure out what the selection of the strain is, but we don't anticipate and our goal is not to impact the timely availability of vaccines,' said Dr. David Kaslow, director of the FDA's Office of Vaccines Research and Review.
The voting members of the FDA's Vaccine and Related Biological Products Advisory Committee agreed that next respiratory season's shots should target the JN.1 family of viruses that swept the globe last year, although they stopped short of making a specific recommendation.
The JN.1 branch of the Omicron family tree was a big shift from the viruses that came before, and it quickly replaced the XBB lineage viruses that had been circulating. It has sprouted its own descendants, which are now the predominant variants.
Although JN.1 and its offshoot KP.2 – the sublineage used to make the Pfizer and Moderna Covid-19 vaccines in the US last year – are no longer circulating, several more viruses derived from them continue to drive Covid-19 transmission. They're all part of the JN.1 family, and so vaccines based on that virus are still protective.
Last week, the World Health Organization said that single-strain inoculations based on JN.1 or KP.2 remain 'appropriate' choices.
The FDA advisory committee heard evidence from vaccine manufacturers that vaccination with JN.1-or KP.2-based shots continues to boost antibodies to protective levels, even against newer viruses with slightly different mutations.
But manufacturers also presented data showing that updated shots based on a newer member of the JN.1 family – LP.8.1, which is currently the dominant variant in the US – could boost antibodies even more robustly.
'We need to stay ahead of this virus, as opposed to behind it,' said committee member Dr. Hayley Gans, a pediatrician at Stanford, who said she favored updating the vaccine formula for the fall to LP.8.1. 'I think what we need to do is to have the most effective vaccine, not one that predicts that it would be less effective down the line.'
Committee member Dr. Eric Rubin, a professor of immunology and infectious disease at the Harvard T.H. Chan School of Public Health and editor of the New England Journal of Medicine, agreed. 'The data suggest that there are not enormous differences right now, but we're trying to pick an antigen for the future, and not an antigen for now.'
Kaslow said the FDA would decide on the specific composition of the 2025-26 vaccine shortly so manufacturers could have the shots ready in time for the fall.