(Wired) – The “super flu” behind outbreaks in the US and UK is a new variant of influenza A H3N2, subclade K. Here’s what you need to know.

The spread of influenza became more severe this fall, particularly in the United States and the United Kingdom. The US Centers for Disease Control and Prevention has designated the 2024-25 flu season as the most severe season since 2017-18. In the UK, the spread has begun earlier than at any time since 2003-04.

Against this backdrop, some media outlets have begun using the term “super flu.” However, this term is not an official medical term. The actual name is “subclade K,” a new variant of influenza A H3N2. (Read More)