FDA Approves XFG-Adapted COVID-19 Vaccine, mRNA for the 2026-2027 Season

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The FDA has approved the supplemental Biologics License Application for Pfizer and BioNTech's 2026-2027 formula of COVID-19 vaccine, mRNA (Comirnaty XFG), clearing the updated shot for adults 65 years and older and for individuals ages 5 through 64 years with at least 1 underlying condition that increases their risk for severe COVID-19 outcomes. The approval marks the companies' latest strain update to the mRNA vaccine platform and follows a now-familiar seasonal cadence of realigning vaccine composition with circulating SARS-CoV-2 lineages. Shipping began immediately following authorization, with doses expected in pharmacies, hospitals, and clinics within days.¹

What Is the COVID-19 Vaccine, mRNA (Comirnaty XFG)?

Comirnaty XFG is a nucleoside-modified mRNA vaccine built on BioNTech's proprietary mRNA platform. It works by delivering lipid nanoparticle-encapsulated mRNA that instructs cells to transiently produce the SARS-CoV-2 spike glycoprotein, prompting an adaptive immune response without exposure to live virus. This iteration swaps the prior LP.8.1 spike sequence for one derived from the JN. 1-lineage XFG subvariant, the strain the FDA identified as the preferred vaccine target for the coming respiratory season.^1,2

Evidence Supporting the Approval

The FDA based this approval on the cumulative body of clinical, nonclinical, and real-world evidence Pfizer and BioNTech have generated across prior Comirnaty formulas, combined with manufacturing and quality data specific to the XFG update. Nonclinical immunogenicity data showed that the XFG-adapted vaccine elicited robust immune responses against XFG and several other currently circulating lineages, including XFG.1.1, NB.1.8.1, and PQ.17. That evidence built on the FDA's Vaccines and Related Biological Products Advisory Committee's May 2026 review of viral surveillance, antigenic characterization, and human immunogenicity data, which concluded that a monovalent JN. The 1-lineage XFG vaccine represented the best match to anticipated fall 2026 circulation. More than 5 billion Comirnaty doses have now been distributed globally, a real-world safety base the agency also weighed in reaching its decision.^1,2

REFERENCES

1. Pfizer and BioNTech receive U.S. FDA approval for XFG-adapted COVID-19 vaccine. News release. Pfizer Inc. August 27, 2026. Accessed August 27, 2026. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-receive-us-fda-approval-xfg-adapted

2. COVID-19 vaccines (2026-2027 formula) for use in the United States beginning in fall 2026. FDA. Updated May 29, 2026. Accessed August 27, 2026. https://www.fda.gov/vaccines-blood-biologics/industry-biologics/covid-19-vaccines-2026-2027-formula-use-united-states-beginning-fall-2026