influenza (flu) is an acute viral illness that can kill even healthy people. unfortunately the influenza virus changes a little each year and scientists have to make educated guesses about which forms of the virus will be infecting people and circulating each year. based on the best available evidence they create a vaccine each year containing three of the likely influenza virus types. there are two types of vaccine: a live attenuated vaccine (nasal spray) and an inactivated vaccine (shot). you cannot get the flu from getting the flu shot because it has inactivated virus (killed virus with heat or chemicals). the immunity from the vaccines is limited and vaccinations must be repeated yearly. in august 2008 the advisory committee on immunization practices changed the recommendation on adolescents. it is now recommended that all people between 6 months and 18 years of age receive an annual vaccination. although the cdc encourages that any adult who wants to decrease the chance of getting the flu to get the influenza vaccine certain high-risk groups are recommended to always get the annual flu vaccine. adults over 50 years of age are considered to be at high risk and should receive the yearly influenza vaccination
what is the influenza vaccine and who should receive it?