Vaccine side effects vary from none to transient pain or discomfort at the inoculation site. Some children may develop a mild fever, headache , and feel tired. In most individuals who get these side effects, Tylenol can reduce the discomfort. These effects rarely last more than 24 hours. Infrequently, some children may develop more severe allergic reactions (swelling, short of breath, Guillain-Barré syndrome); these individuals should not be given vaccine. Consultation with a pediatric specialist ( allergy and/or infectious disease) is recommended.