Flu

Influenza (The Flu)

What is the flu? Influenza (the flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to death. The best way to prevent the flu is by getting a flu vaccination each year. Every year in the United States, an average of 5 percent to 20 percent of the population gets the flu; more than 200,000 people are hospitalized from flu complications, and about 36,000 people die from it. Some people, such as the elderly, young children, and people with certain health conditions are at high risk for serious flu complications.

Complications of flu. Complications resulting from the flu may include pneumonia, ear infections, sinus infections, dehydration, and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes.

How flu spreads. Flu viruses spread mainly from person to person through coughing or sneezing on people with influenza. Sometimes people may become infected by touching something with flu viruses on it and then touching their mouth or nose. Most healthy adults may be able to infect others beginning one day before symptoms develop, and up to five days after becoming sick. That means you may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick.