Side-effects of the anti-influenza drug Tamiflu may have been underreported, a new analysis suggests.

Influenza rates have been increasing despite the unseasonally warm weather across large parts of Canada, data shows, though it hasn't been a bad year for flu overall.

After a lull of several months, an influenza virus that is sporadically jumping from pigs to people in the United States has made another appearance.

The U.S. Centers for Disease Control and Prevention has reported the lowest influenza infection rate in 30 years of tracking flu activity, as well as the slowest recorded start to the flu season.