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

Flu season is starting to ramp up as the U.S. settles into the colder weather months and indoor gatherings potentially fuel the spread of viruses.

A new version of the common flu is spreading globally, and health officials are monitoring this evolving strain of influenza ...

The latest data on respiratory illness in the United States shows that shoppers and merry-makers are spreading more than just holiday cheer: They’re also passing around germs. In many cases, it’s a ...

Seasonal flu activity is up across the United States, according to data from the Centers for Disease Control and ...