influenza virus

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…manufactured for use that fall. Immunity develops one to two weeks after the shots. The vaccine is made from dead viruses so people can't get the flu from a flu shot. However, people allergic to eggs should avoid the vaccine since they are grown in chicken eggs. The vaccine can reduce the rate of occurrence in people over 60 by half. If people do get the flu even though they're vaccinated, they usually experience milder symptoms.