Try to get it no later than November, if possible. Eggs are used in the production of flu vaccine. If you are allergic to eggs, you may have a severe allergic reaction to the flu shot. The flu shot should not be taken by anyone who has a history of severe egg allergy. Some manufacturers also recommend not getting a flu shot if you have an allergy to thimerosal.
Thimerosal is a preservative used in contact lens solutions and the flu vaccine.
For people who do not have egg or thimerosal allergies, the flu vaccine has infrequent, minor side effects. The most common reaction is some soreness at the site of the shot. A few people develop fever or muscle aches within a few hours of the injection. These symptoms may last 1 to 2 days. There have been no reports of flu shot complications affecting the nervous system since the 1976-1977 swine flu epidemic.