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The best way to protect yourself from influenza is to receive an annual influenza vaccine. This will immunize you against one or more strains of the virus. A flu vaccine uses an inactivated virus that cannot cause infection but instead, causes the body to produce antibodies (proteins that fight the virus). The vaccine is based on the strains of the flu viruses that are common at the time. Flu viruses change over time. That is why you must get a new shot every fall. Even then, some people may still catch a different type of flu that scientists were not expecting.

Flu shots are usually given at doctors’ offices and in health departments in the fall and winter. Now they are also offered at places in your neighborhood like drugstores. You should get vaccinated 6 to 8 weeks before flu season begins to give your body time to acquire immunity. This should prevent you from getting infected or at least reduce the severity of flu if you do catch it. However, if you are exposed to the virus soon after you are vaccinated you may still catch it. That is why you should get the shot early in the flu season.

The vaccine itself cannot cause the flu, but as with almost any medical procedure, there may be side effects of the vaccine. The most common side effect is mild soreness where the shot was given. Soreness can last up to two days and rarely affects daily activities. A small number of people, most often children, might also develop a slight fever within 24 hours. They may have chills or a headache, or feel a little sick. People who already have a cold or breathing problem may find their symptoms worsen. Usually none of these reactions lasts for more than a few days. Because the vaccine virus is grown in chicken eggs, a few people who are allergic to eggs are in danger of allergic reaction, but this is rare. If you are concerned, ask your doctor. You can be treated for the allergy.