A Food and Drug Administration (FDA) advisory panel on Thursday recommended updating this fall’s COVID-19 vaccines to target the XFG variant, a fast-growing strain also known as “stratus.” Eight out of nine members of the FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) voted in favor of the recommendation, with one member abstaining.

The panel’s decision follows concerns about limited data on circulating variants. According to wastewater surveillance data, XFG strains accounted for more than half of U.S. cases over the four weeks ended April 11. However, the Centers for Disease Control and Prevention’s (CDC) COVID dashboard reports new data as unavailable due to low sequencing submissions.

Anna Durbin, a VRBPAC member, stated: “We can’t make a recommendation if we don’t have data, and that’s one of my great concerns.” She urged strengthening real-time surveillance infrastructure and suggested the committee meet more frequently than once annually.

The recommendation aims to help vaccine manufacturers prepare for the upcoming fall and winter seasons when seasonal infections typically surge. Thursday’s meeting marked the first VRBPAC session since FDA Commissioner Marty Makary resigned, though his departure did not influence the panel’s outcome.

Health Secretary Robert F. Kennedy Jr. has been noted for actions that have undermined confidence in vaccines nationwide. Meanwhile, CDC surveillance efforts have been scaled back due to funding reductions, exacerbating data gaps.

The XFG variant is particularly concerning because it may evade immunity from prior infection or vaccination.