What is the flu shot?
The flu shot is an inactivated vaccine (containing killed virus) that is given with a needle, usually in the arm. It contains three seasonal influenza viruses. The three seasonal vaccine viruses – one A (H3N2) virus, one regular seasonal influenza A (H1N1) virus (not the 2009 H1N1 virus), and one B virus – are representative of the seasonal influenza vaccine strains recommended for that year. Viruses for the flu shot are grown in eggs. A seasonal flu shot will not protect against 2009 H1N1 flu.
