All children will have baseline blood samples drawn and will then be vaccinated with licensed and approved influenza vaccines. Following the recommendation from the Advisory Committee on Immunization Practices, children 5-8 years old will preferentially receive live attenuated influenza vaccine (LAIV). Children aged 9-17 will be randomized to receive either LAIV or inactivated influenza vaccine (IIV). Children with a medical contraindication to any licensed influenza vaccine will be excluded from the study.