Influenza is surging in the U.S., with doctor's visits for flu symptoms at a 15-year high. Why is this flu season so bad?

Flu cases soar across the US; Sacramento sees highest flu-related medical visits since 2009. Learn prevention tips and why vaccination rates matter.

Influenza levels in the US are the highest they've been in 15 years amid winter weather and a second wave of the virus.

Flu infections are at or near their highest levels in at least 15 years and are still rising, the Centers for Disease Control ...

With data showing a significant rise in flu cases nationwide, medical experts are describing it as the worst flu season since ...