An FDA committee voted unanimously June 5 on the 2024-2025 COVID-19 vaccine makeup, recommending it should be one that targets the monovalent JN.1-lineage.
Jerry Weir, PhD, director of the FDA's division of viral products' office of vaccines research and review, said before the vote that "JN.1 has continued to evolve, and it makes it somewhat difficult to pick the specific string to be used" for the composition of the next fall COVID vaccine.
JN.1 emerged in September 2023 and by late December accounted for a majority of circulating COVID-19 infections in the U.S.
Following the vote, the Vaccines and Related Biological Products Advisory Committee also discussed whether the new vaccines should target a specific sub-lineage of JN.1, such as the KP.2 lineage, which emerged out of the JN.1 family.
KP.2 is part of what has been called the "FLiRT" variants, which references COVID-19 strains that have been named to the group because of technical names for the variants' mutations in their spike proteins, according to the American Medical Association.
Right now, KP.2 accounts for 28.5% — the largest percentage of any strain at this time — of circulating COVID-19 infections in the U.S. per CDC data.
Behind it in order of percent of infections are also borne from the same lineage with: KP.3 making up 12.7% of COVID cases, JN.1.7 accounting for 9.2%, KP.1.1 accounting for another 9.2% of cases, and the original JN.1 currently making up 8.4% of cases.
The panel did not vote on whether the next vaccine should target any more specific version of the JN.1 lineage, but will consider that along with its final recommendation in the coming weeks.