Study links mRNA flu vaccine to sustained immune response

SEOUL, South Korea – An investigational mRNA influenza vaccine produced broader and more diverse antibody responses than a conventional flu vaccine in a study led by researchers from Korea University College of Medicine.

The study compared the quadrivalent mRNA-1010 vaccine with the licensed Fluarix vaccine and found that influenza-specific germinal-center responses persisted for up to 26 weeks in some participants who received the mRNA vaccine. Germinal centers are sites where B cells mature and develop into high-affinity antibody producers and long-lived immune memory. It was published in Nature Immunology on June 15, 2026.

Researchers followed 75 healthy adults ages 20 to 50 across two influenza seasons. Thirty-eight participants received mRNA-1010, and 37 received Fluarix. Researchers collected blood samples for 26 weeks, and a subset of participants underwent draining lymph node sampling to assess germinal-center activity.

“We found that the mRNA vaccine elicited a substantially more diverse and broader serum antibody repertoire than Fluarix,” said Jiwon Lee, associate professor in the Department of Convergence Medicine and Vaccine Innovation Center at Korea University College of Medicine.

Researchers detected persistent influenza-specific germinal centers at 26 weeks in five of 13 mRNA-1010 recipients evaluated for the response, whereas they did not detect persistent germinal centers among Fluarix recipients.

Researchers also found that the mRNA vaccine increased the diversity of the serum IgG antibody repertoire and promoted diversification of existing B-cell lineages. These changes were associated with broader antibody binding across different influenza strains and greater increases in neutralizing antibody levels against 11 of 13 A/H1N1 viruses tested.

“The mRNA platform does not simply produce more antibodies, it produces a more diversified antibody response, which leads to greater binding and neutralizing breadth,” said Lee.

The research team used several methods to characterize immune responses, including single-cell RNA sequencing, B-cell receptor sequencing, and Ig-Seq, a mass spectrometry-based technology that identifies individual antibody clonotypes circulating in the blood after vaccination.

The study, conducted with Ali Ellebedy and his research group at Washington University in St. Louis, was published in Nature Immunology in June.

Researchers said additional studies are needed to determine whether broader immune responses translate into longer-lasting or multi-season protection against influenza and whether similar benefits occur among older adults and immunocompromised populations.