Seasonal Influenza: The Disease

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. Some people, such as older people, young children, and people with certain health conditions, are at high risk for serious flu complications. The best way to prevent the flu is by getting vaccinated each year.

In 2009-2010, a new and very different flu virus (called 2009 H1N1) spread worldwide causing the first flu pandemic in more than 40 years. CDC expects the 2009 H1N1 virus to cause illness again this upcoming season along with other seasonal flu viruses. The 2010-2011 flu vaccine will protect against 2009 H1N1 and two other influenza viruses.

Flu Information

Key Facts About Seasonal Flu
A summary of key seasonal flu facts and who should get vaccinated…

Symptoms & Severity
Flu symptoms and how some people are at greater risk from severe complications…

People at High Risk from Flu
Some people are more likely to get flu complications that result in being hospitalized and occasionally in death…

How Flu Spreads
How the virus spreads and how long people may be contagious…

Regular Flu Season
General information on regular flu seasons in the United States…

Content source: Centers for Disease Control and Prevention