U.S. flu infections still are surging, and health officials say it's a severe season that's likely to get worse.

WASHINGTON (AP) — Flu is rising rapidly across the U.S., driven by a new variant of the virus — and cases are expected to ...

At least 14 states and Washington, DC, are seeing high and very high levels of flu, mainly caused by a surprise new influenza mutation called subclade K.

A new form of the flu, which is highly contagious and aggressive, is sweeping the nation this season. A mutation of influenza ...

As flu cases rise across the U.S., those who end up contracting the virus have treatments available that may help reduce ...

Subclade K has become the dominant form of flu and is slightly different from the virus targeted by this year’s flu vaccine.

Known as subclade K, a new, mutated flu strain that has dominated in Europe and Asia is now rapidly spreading across the US.

This year’s influenza virus has been dubbed the “super flu” for how quickly it’s spreading — and how hard it’s hitting.

U.S. flu infections are still surging, and health officials say it's a severe season that's likely to get worse.