Loading ...

The FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) voted almost unanimously in support of an updated monovalent COVID vaccine for 2026-2027 that targets the XFG variant, part of the JN.1 family descended from Omicron. 

In a scheduled meeting, the VRBPAC heard presentations from vaccine manufacturers Sanofi, Moderna, and Pfizer with data including currently circulating strains and potential effectiveness of XFG vaccines against several COVID variants in the JN.1 family.

Eight of nine VRBPAC members (one abstained) voted in support of XFG, which remains the dominant strain in the United States, although COVID-19 cases in the US overall are low. 

XFG was identified as a “variant under monitoring” by the World Health Organization (WHO) in June 2025. However, the WHO recently advised manufacturers to develop next season’s vaccine with a monovalent LP.8.1 antigen for the next COVID vaccine rather than XFG because its impact appears to be decreasing, according to a WHO press release. According to the WHO, “the available evidence on XFG does not suggest additional public health risks relative to the other currently circulating Omicron descendent lineages.”

In the United States, the JN.1 family accounts for more than 80% of COVID sequences collected between May 1, 2025, and April 30, 2026 — 66% of which were XFG, and less than 1% were LP.8.1, according to data presented by Moderna. Moderna’ data on neutralization titer modeling also supported XFG as more immunogenic against JN.1 variants. 

Data presented by Sanofi were similar, and presenter noted that LP.8.1 has not been circulating in the US for approximately the past 9 months. The Sanofi presentation also included human serological data showing an advantage of an XFG vaccine to overcome immune escape more effectively than a vaccine targeting other strains.

The Pfizer presentation noted the effectiveness of the previous LP.8.1- based vaccine and cited similar evidence of immunity between LP.8.1 and XFG in nonclinical models. 

Efficacy of Prior Vaccines Consistent Across Populations 

Amanda B. Payne, PHD, MPH, of the CDC, presented data from two CDC networks, the VISION Vaccine Effectiveness Network, and Investigating Viruses in the Acutely Ill (IVY) network, on the effectiveness of previous COVID vaccines in the 2023-2024 and 2024-2025 seasons. Overall, mRNA COVID vaccines protected against severe COVID, including during times when variant strains were surging — although protection was less stable against highly divergent lineages, Payne noted.

The 2025-2026 vaccine focused on the LP.8.1 strain, although both that and XFG are descended from the JN.1 lineage that traces back to Omicron. Early interim results from 2025-2026 show vaccine-associated protection against COVID-associated emergency department visits and hospitalizations among immunocompromised and non-immunocompromised individuals, Payne said.