THE FLU | What you should know

Influenza is caused by a virus that spreads from infected people to the nose or throat of others. It can cause fever, cough, sore throat, headache, chills and muscle aches, and it kills an average of 36,000 people each year in the United States, mainly among the elderly.
Inactivated (dead) influenza vaccine cannot cause flu. Protection develops about two weeks after getting the shot. People who get the vaccine may still get the flu, but it is usually a milder case.
People at high risk for getting a serious case of the flu include those over age 49; residents of long-term care facilities housing people with chronic medical problems; and people who have long-term health problems such as heart, lung and kidney disease, metabolic diseases such as diabetes, asthma, and anemia and other blood disorders.
CDC recommends that people at high risk for getting a serious case of the flu, and people in close contact with them, get the shot.
CDC encourages shots for healthy children 6 to 23 months of age, and those living with them, and out-of-home caretakers of infants from 0 to 23 months of age; people who provide essential community services; people at high risk for flu complications who travel to the Southern hemisphere between April and September, or who travel to the tropics or in organized tour groups at any time; people living in dormitories or under other crowded conditions and anyone else who wants to reduce their chance of catching influenza.
The best time to get a flu shot is in October or November, but people at risk should get their shots as early as possible. The flu seasons usually peaks between January and March.
People who have had a serious allergic reaction to eggs or to a previous dose of flu vaccine, or have a history of Guillain-Barre Syndrome (GBS), should talk to their doctor before getting the flu shot.
Reactions to the flu shot are possible. If there is a moderate or severe reaction, such as high fever, behavior changes, difficulty breathing, hoarseness or wheezing, hives, paleness, weakness, a fast heart beat or dizziness, call a doctor.