Early influenza virus characterisation and vaccine effectiveness in England in autumn 2025, a period dominated by influenza A(H3N2) subclade K
Influenza A(H3N2) subclade K (J.2.4.1) has dominated the 2025/26 season start in England. Post-infection ferret antisera raised against northern hemisphere 2025/26 vaccine strains showed reduced reactivity to subclade K viruses in England, aligning with World Health Organization reports. Nevertheless, early post-vaccination, vaccine effectiveness against influenza-related emergency department attendances and hospital admissions remained within typical ranges, at 72-75% in children and adolescents (< 18 years) and 32-39% in adults. Hence, vaccination remains effective against clinical disease caused by influenza A(H3N2) viruses.
Authors
- Heather Whitaker (ORCID: https://orcid.org/0000-0001-5833-1863)
- Tiina Talts (ORCID: https://orcid.org/0009-0008-1534-278X)
- Nicora Gardner
- Alex Allen
- Anika Singanayagam (ORCID: https://orcid.org/0000-0002-2572-0173)
- Katja Höschler (ORCID: https://orcid.org/0000-0003-4837-0433)
- Conall H. Watson (ORCID: https://orcid.org/0000-0002-2469-791X)
- Jamie Lopez Bernal (ORCID: https://orcid.org/0000-0002-1301-5653)
- Nurin Iwani Binti Abdul Aziz (ORCID: https://orcid.org/0000-0002-8098-6935)
- Christopher Rawlinson
- Maria Zambon (ORCID: https://orcid.org/0000-0002-8897-7881)
- Beatrix Kele (ORCID: https://orcid.org/0000-0003-1273-7299)
- Mary Ramsay (ORCID: https://orcid.org/0000-0002-7156-7640)
- Rebecca E Green
- Catherine Quinot (ORCID: https://orcid.org/0009-0002-5634-7073)
- Nick Andrews (ORCID: https://orcid.org/0000-0003-2069-2684)
- E. F. Waller
- Freja Kirsebom (ORCID: https://orcid.org/0000-0003-4585-319X)
- Sarah E. McDonald (ORCID: https://orcid.org/0000-0003-2776-7415)
- Richard Pebody (ORCID: https://orcid.org/0000-0002-9069-2885)
- Catherine Thompson
Institutions
- National Security Agency (US)
- Public Health England (GB)
- London School of Hygiene & Tropical Medicine (GB)
- NIHR Imperial Biomedical Research Centre (GB)
- Public Health Agency (GB)
- Imperial College London (GB)
Publication Details
- Journal
- Eurosurveillance
- Published
- 2025-11-20
- DOI
- https://doi.org/10.2807/1560-7917.es.2025.30.46.2500854
- Citations
- 32
- Primary Topic
- Influenza Virus Research Studies
- Type
- article
- Field-Weighted Citation Impact
- 43.33