March 6, 2024 -- An FDA advisory committee has recommended that the United States switch from a quadrivalent to trivalent influenza vaccine for the next flu season.
The flu vaccine currently in use targets two A strains and two B strains. But the Yamagata/B subtype, which was already in decline, has not been detected worldwide since March 2020, the FDA said. Social distancing and other precautions used to avoid COVID apparently finished it off.
In response to that change, the Vaccines and Related Biological Products Advisory Committee (VRBPAC) voted Tuesday to recommend the three-strain flu shot.
VRBPAC recommended the egg-based flu vaccines contain an A/Victoria/4897/2022 (H1N1)pdm09-like virus, an A/Thailand/8/2022 (H3N2)-like virus; and a B/Austria/1359417/2021 (B/Victoria lineage)-like virus.
The committee recommended the cell- or recombinant-based flu vaccines contain an A/Wisconsin/67/2022 (H1N1)pdm09-like virus; an A/Massachusetts/18/2022 (H3N2)-like virus; and a B/Austria/1359417/2021 (B/Victoria lineage)-like virus.
The move is no surprise. The World Health Organization and FDA experts had been recommending the change since last year.
Jerry Weir, MD, director of the FDA’s Division of Viral Products, said companies that make flu vaccines should have the trivalent shot ready for the 2024-2025 flu season.
“Each of the U.S. influenza vaccine manufacturers have submitted updated regulatory files related to a trivalent influenza vaccine, and approval of all the necessary regulatory submissions is on track for 2024-25,” he said during the advisory committee’s meeting, according to CNN.
“FDA anticipates that there will be an adequate and diverse supply of approved trivalent seasonal influenza vaccines for the United States in the coming season,” the agency said.
U.S. flu vaccine manufacturers will still make a four-strain vaccine for distribution to overseas markets, CNN said.