The Disease: Influenza is a contagious disease caused by the influenza virus. It spreads from person to person by coughing or sneezing. Anyone can get influenza. For most, symptoms such as fever, cough, sore throat, headache, muscle aches and fatigue will last only a few days. Some will get much sicker. Influenza can lead to pneumonia and can be dangerous for people with breathing conditions. It can cause high fever and seizures in children. Influenza kills about 36,000 people each year in the United States.

The Vaccine: There are two types of influenza vaccine. An inactivated vaccine or “flu shot” has been used in the United States for many years. It is given by injection.

A live, weakened vaccine was licensed for use in 2003. It is sprayed into the nostrils.

Because influenza viruses are always changing, the vaccines are updated each year. Therefore, vaccination is recommended each year.

It takes about 2 weeks for protection to develop after vaccination and protection can last up to a year.

Side effects: The inactivated, “flu shot” can cause mild problems such as fever, aches and soreness, redness or swelling where the shot was given.

The live, weakened, nasal vaccine can cause mild reactions such as runny nose, nasal congestion, cough, fever, headache and occasional vomiting or diarrhea in some children and adolescents. These symptoms should not last long and should go away on their own.

For more information, the Center for Disease Control has handouts available for both types of flu vaccine.

For information on the inactivated vaccine, or "flu shot", click here.

For information on the live, weakened vaccine that is sprayed into the nostrils, click here.