When you are injected with the flu vaccine, your body reacts as
if it has been infected with the actual living virus and makes
antibodies that provide immunity against the real virus. These
antibodies remain at high levels for only six to nine months.
These waning antibody levels are one reason why you need to be
revaccinated each year. The main reason you should be
revaccinated yearly is the flu virus is constantly changing and
evolving into new strains. Each year the CDC attempts to predict
which flu strain will be predominant. The CDC works with vaccine
manufacturers to produce the specific vaccine that will combat
the predicted strain. If you are concerned about the cost of a
flu immunization, check with your local health department for
locations in your area where free flu shots are given. Treating
yourself at home When you are exposed to the flu, the virus
incubates for three to five days before symptoms begin. You
probably have the flu if you come down with a high fever, sore
throat, muscle aches, a ru