This means that last year's immunization may not be effective against this year's viruses. Annual immunization is required for effectiveness. The annual outbreaks of influenza usually begin in December. The vaccine requires about two weeks to become effective. The best time for immunization is in October or November.
Protection provided by the vaccine lasts about four to six months.
The influenza season in the U.S. ends in March, so one properly timed immunization is usually effective. It requires only a single dose of vaccine. For more information, see the Center for Disease Control . Most people are familiar with diabetes as a sugar disorder. The body lacks enough of the hormone insulin to fully use sugar in the diet.