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2025-2026 Influenza Vaccine Effectiveness

The effectiveness of the 2025-2026 influenza vaccine against the dominant H3N2 subclade K

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Jan 10, 2026

How effective are the 2025–2026 flu vaccines against the new H3N2 J.2.4.1 (K) subclade?

Early, multi-country data indicate the 2025–2026 seasonal vaccines provide meaningful but imperfect protection against the emergent H3N2 J.2.4.1 (subclade K): strong protection in children (roughly 72...

Jan 10, 2026

How effective is the 2025-2026 influenza vaccine against current circulating strains?

The 2025–2026 influenza vaccine provides meaningful protection overall but is an imperfect match against the currently dominant H3N2 subclade K; early estimates show strong protection against severe o...