Published: 9 December 2025 A heavily mutated flu strain ā A/H3N2 subclade K, often dubbed the āK-strainā or āsuperfluā ā is now dominating the 2025ā26 flu season and driving record levels of illness in parts of the UK and beyond. On Tuesday, new analysis showed that this K-strain now accounts for around 90% of flu samples in the UK and Japan and has been detected on every …
