Overview
- Mexico’s health ministry confirmed its first detected case of the H3N2 K subclade via INER, reported the patient recovered after antivirals, and said surveillance is being reinforced, including monitoring at Mexico City’s airport.
- WHO and regional data show the seasonal peak has arrived 3–6 weeks early in the Northern Hemisphere with high hospital demand, and the UK health agency has projected up to 8,000 influenza hospitalizations in a peak week in England.
- CDC labels the K subclade antigenically distinct from the 2025–2026 vaccine strain, noting reduced protection against infection while emphasizing continued efficacy in preventing severe outcomes and hospitalizations.
- ECDC reports the K subclade is predominant in Europe and accounted for roughly one‑third of global A(H3N2) sequences from May to November, as countries reintroduce masking in healthcare settings and activate surge protocols.
- Co-circulation of RSV and SARS‑CoV‑2 is complicating diagnosis and straining services, prompting recommendations for combined testing, timely antivirals for high‑risk patients, and renewed vaccination campaigns.