Influenza A(H3N2) subclade K (J.2.4.1) viruses associated with a surge at a university health clinic, Arizona, the United States, November to early December 2025

Eurosurveillance 2026 Open access

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Authors: Matthew Scotch, Temitope O. C. Faleye, Angelica Urquidez-Negrete, Bradley Bobbett, Veronica Boyle, Kelly Conard, Lucy Sublasky-Rodriguez, Vel Murugan
DOI: 10.2807/1560-7917.es.2026.31.7.2600111
Cited by: 4
References: 7

Abstract

Genomic surveillance during an influenza surge between November and early December 2025 at a university health clinic in the United States identified A(H3N2) subclade K (J.2.4.1) viruses with shared haemagglutinin amino acid substitutions in antigenic sites and the receptor-binding domain. An epitope-based model indicated reduced vaccine protection (mean predicted protection 0.13). Phylodynamic analyses suggested multiple introductions with onward campus-to-community spread, highlighting that universities and other semi-closed settings can amplify transmission and aid early characterisation of emerging lineages.

Fields of Study & Subjects

Influenza Virus Research Studies Respiratory viral infections research SARS-CoV-2 and COVID-19 Research

Publication details

Journal / source
Eurosurveillance
Publisher
European Centre for Disease Control and Prevention (ECDC)
Volume
31
Issue
7
Publication date
19 February 2026
Language
EN