Children and adults across England are receiving strong protection from this year’s flu vaccine, despite the emergence of a new subclade driving an unusually early flu season.

New data published today as a pre-print by the UK Health Security Agency (UKHSA) shows the 2025/26 vaccine is currently 70 to 75% effective at preventing hospital attendance in children aged 2 to 17 years and 30 to 40% effective in adults.

The early findings confirm the vaccine provides important protection even though a drifted influenza A(H3N2) strain (also now known as subclade K) currently dominates cases in England, so the protection levels observed in children are particularly encouraging this year. Flu vaccine effectiveness varies from season to season but is typically between 30 to 60%, with higher vaccin

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