Journal article
Extended influenza seasons in Australia and New Zealand in 2025 due to the emergence of influenza A(H3N2) subclade K viruses
C Dapat, H Peck, L Jelley, T Diefenbach-Elstob, T Slater, S Hussain, P Britton, AC Cheng, T Wood, A Howard-Jones, YM Deng, JE Miller, QS Huang, IG Barr
Eurosurveillance | Published : 2025
Abstract
In Australia and New Zealand, late outbreaks of an A(H3N2) variant virus termed subclade K extended the 2025 influenza season. Subclade K viruses were genetically and antigenically distinct from the 2025 vaccine A(H3N2) strain A/Croatia/10136RV/2023 (H3N2)-like virus and previously circulating subclade J viruses. Subclade K viruses have since been detected in over 34 countries and appear to have spread glob-ally, except in South America. It is thus likely that they will further expand during the northern hemisphere winter 2025/26 season.