Flu facts

The flu is a respiratory (i.e., nose, throat, and lung) infection that can be caused by a variety of influenza viruses. Many people use the word flu when they actually have a cold. Although the common cold is also caused by viruses, the flu and common cold differ in several ways.

In North America, flu almost always strikes from October to March. Stronger epidemics come every 2 or 3 years, infecting twice as many people as during an "off" year. Most people who get the flu will recover within 1 or 2 weeks, but some people develop complications such as pneumonia. On average, about 30,000 people die each year in North America from complications of influenza. Most of these people have other medical conditions, are elderly, or are very young children.