Advisers to the Food and Drug Administration on Thursday recommended updating COVID-19 vaccines to target one of the most common coronavirus strains now circulating in the U.S.
The panel, made up of independent vaccine and infectious disease experts, voted 21-0 in favor of modifying the vaccines to target a version of omicron known as XBB, rather than both the original and BA.1 omicron variants that the shots are currently aimed at.
XBB and its related subvariants, particularly one dubbed XBB.1.5, now account for most new COVID-19 cases in the U.S., according to the Centers for Disease Control and Prevention.
At Thursday’s meeting, Pfizer, Moderna and Novavax each presented preclinical data suggesting that new vaccines they’re developing could spur protective antibodies against that strain. All three manufacturers said they are prepared to supply updated XBB-targeting candidates later this year.
Yet the committee had different views on how often to update vaccines moving forward. While all agreed a new version is needed, some weren’t yet convinced COVID should be treated the same as influenza, for which shots are altered on a regular, annual basis.
“I don’t think we should provide any language or communication that restricts [the vaccine’s] administration” to the typical flu season, said Michael Nelson, a panelist and chief of the division of asthma, allergy and immunology at UVA Health. “We currently have biphasic summer and fall peaks. Yes, they’re smaller than they have been previously, but that summer peak is not going away.”
COVID upticks throughout the year make it harder to predict a single peak season when most infections would occur. Committee members were also concerned that setting vaccination schedules to follow the flu season could cause confusion among the public.
"We have to do better because we have not done a good job today communicating to the American public what's going on here, because they’re still not getting these vaccines in the way we’d like to potentially see people [get them],” said Peter Marks, head of the FDA division that reviews vaccines.
Still, for manufacturing reasons, Marks described yearly updates as a practical solution.
The committee discussed whether to narrow their recommendation to apply only to this year, rather than 2024 as well. But Marks noted how an updated formulation will be used this year and the next, while Jerry Weir, director of the division of viral products, reminded the committee that it planned to meet at least once a year to discuss updates.
“This is not going to be the final formulation of this vaccine forevermore,” Marks said.
While the FDA typically follows the advice of its advisory committees, it’s not required to. The regulator is expected to soon make a decision on its desired formulation.
While hospitalizations and deaths from COVID have been at lower levels, CDC officials presented data showing severe disease remains higher in older age groups, suggesting a need to reinforce protection for those who are most vulnerable.
All of the current vaccine manufactures indicated they would be ready to meet the FDA’s recommendation.
Moderna has a XBB.1.5-targeting candidate it said it can submit for clearance later this summer ahead of any fall spike in infections. During its presentation Thursday, Pfizer said it could supply an updated vaccine by the end of July.
Novavax, which never saw its shot become a widely used option in the U.S., said it could have a version of its protein-based vaccine targeting the XBB.1.5 strain by the fall.