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

[tetano]

• Matthew Scotch[SUP]1[/SUP] , Temitope OC Faleye[SUP]1[/SUP] , Angelica Urquidez-Negrete[SUP]1[/SUP] , Bradley Bobbett[SUP]1[/SUP] , Veronica Boyle[SUP]1[/SUP] , Kelly Conard[SUP]1[/SUP] , Lucy Sublasky-Rodriguez[SUP]1[/SUP] , Vel Murugan[SUP]1[/SUP]

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.

​https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2026.31.7.2600111


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