Safety of vaccination will be assessed using symptoms collected by parents for 7 days after each dose of vaccine. Serum will be obtained prior to and on day 28 following each dose of vaccine and assessed for antibody by HAI, ELISA, B-cell ELISPOT and neutralization techniques. Nasal secretions will be obtained by nasal aspiration prior to and on day 28 after each dose and assessed for HA-specific IgA antibody by ELISA. Nasal swabs will be obtained on days 2, 4, and 7 after each dose of live vaccine and assessed for the presence and magnitude of vaccine virus shedding of the live attenuated vaccine by rtRT-PCR and TCID50 on MDCK cells.