The purpose of this study is to evaluate how young children's bodies learn to fight against flu infection and to see how vaccines may help to fight against the flu. This is a Phase 4, single-center, randomized study of the immune responses of 40 children, ages 5-9, given one of two licensed influenza vaccines (either inactivated vaccine given in an arm muscle or live, attenuated vaccine inhaled through the nose). Study procedures will include up to 3 blood samples. Participants will complete a diary to document any side effects experienced following the vaccination. Participants will return to the clinic for a visit on Day 7-9 and again 4-6 weeks following vaccination. Participants that have not been previously vaccinated will receive a 2nd dose of vaccine. A follow up telephone call will occur 8-10 weeks following vaccination. Total study participation will be up to 75 days.