Influenza (the flu) is a contagious respiratory illness caused by influenza viruses. It spreads from person-to-person and can cause mild to severe illness; and in some cases, can lead to death.

• In the United States, yearly outbreaks of seasonal flu usually happen during the fall through early spring.
• The best way to prevent the flu is by getting a flu vaccination each year.
• Flu viruses can cause illness in people of any age group. Children are most likely to get sick because their immune systems aren’t strong enough to fight off the infection.
• Some groups are more likely to have complications from the seasonal flu. These include:
  • those age 65 and older
  • children younger than 2 years old
  • people of any age who have chronic medical conditions (e.g. diabetes, asthma, congestive heart failure, lung disease)
• Complications from the flu can include:
  • bacterial pneumonia
  • ear or sinus infections
  • dehydration
  • worsening of chronic medical conditions

• CDC recommends a yearly flu vaccine as the first and most important step in protecting against flu viruses.
• While there are many different flu viruses, the flu vaccine protects against the three viruses that research suggests will be most common.
• The 2011-2012 vaccine will protect against an influenza A H3N2 virus, an influenza B virus and the H1N1 virus that emerged in 2009 to cause a pandemic.
• Everyone 6 months of age and older should get a flu vaccine as soon as the 2011-2012 vaccines are available.
• Vaccination of high risk persons is especially important to decrease their risk of severe flu illness.
• People at high risk of serious flu complications include young children, pregnant women, people with chronic health conditions like asthma, diabetes or heart and lung disease and people 65 years and older.
• Vaccination also is important for health care workers, and other people who live with or care for high risk people to keep from spreading flu to high risk people.
• Children younger than 6 months are at high risk of serious flu illness, but are too young to be vaccinated. People who care for them should be vaccinated instead.

The nasal-spray flu vaccine—a vaccine made with live, weakened flu viruses that do not cause the flu (sometimes called LAIV for “live attenuated influenza vaccine” or FluMist®)—is approved for use in healthy* people 2 to 49 years old who are not pregnant. (*“Healthy” indicates persons who do not have an underlying medical condition that predisposes them to influenza complications.)

The “flu shot” is an inactivated vaccine (containing killed virus) that is given with a needle, usually in the arm. The flu shot is approved for use in people older than 6 months. Healthy people and people with chronic medical conditions like asthma can get the shot.