Seasonal vaccine-induced immunity shows preserved cross-reactivity to H3N2 subclade K in adults
Influenza A subclade K viruses caused high infection rates in the 2025/2026 Northern Hemisphere season, raising concerns about antigenic drift and reduced vaccine effectiveness. We measured antibody responses in matched human pre- and post-vaccination sera against a vaccine-like as well as subclade K isolates. Pre-existing immunity to subclade K variants was noted with seasonal influenza vaccination boosting titers two-fold against subclade K and three-fold against the vaccine-like strain, indicating little antigenic drift. These data contrast ferret-based predictions of marked antigenic drift.
Authors
- Charles Gleason
- Enikő Hermann (ORCID: https://orcid.org/0000-0003-3055-0428)
- Brian R Lerman
- Adria R. Wilson
- Jessica Nardulli (ORCID: https://orcid.org/0009-0002-5309-5413)
- Reima Ramsamooj
- Zain Khalil
- Anass Abbad
- Jordan Ehrenhaus
- Ana Gonzalez-Reiche
- Harm van Bakel
- Komal Srivastava_
- Emilia M Sordillo
- Ashley Aracena
- Viviana Simon
- Jacob Mischka
- Yusuf Figueroa
- Florian Krammer
Institutions
- Office of Infectious Diseases (US)
- ID Genomics (United States) (US)
- Mental Illness Research, Education and Clinical Centers (US)
- Global Policy Institute (US)
- Artificial Intelligence in Medicine (Canada) (CA)
- Medical University of Vienna (AT)
- Icahn School of Medicine at Mount Sinai (US)
Publication Details
- Journal
- medRxiv
- Published
- 2026-02-18
- DOI
- https://doi.org/10.64898/2026.02.18.26346502
- Primary Topic
- Influenza Virus Research Studies
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Universität Wien
- Medizinische Universität Wien
- National Institute of Allergy and Infectious Diseases