The winter flu season features two types of influenza. Here's what you need to know about them and how they differ.

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 ...

The U.S. winter virus season is in full force, and by one measure is the most intense in 15 years.

The flu season has reached high levels, with 3,600 children testing positive in the past week across the Norton Children's ...

Ten states and New York City are experiencing the highest levels of flu activity, according to the CDC. Flu cases are surging ...

An infectious disease MD explains for how long you're likely to transmit the flu to others, with her advice for preventing viral infection.