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

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

Seasonal influenza has continued to increase across the country, reaching unprecedented intensity and marking the most severe flu season in at least 15 years, according to the CDC, which reported ...

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

Levels of influenza nationwide are now at the highest they have been since the peak of the 2009 swine flu pandemic, according ...

Outpatient health care visits for flu-like illnesses are at their highest levels in 15 years, according to data updated ...