A Clinical Study to Assess the Safety of a New Influenza Vaccine

This prospective, randomized, double-blind, placebo-controlled release study will enroll approximately 300 healthy adults 18-49 years of age. Eligible subjects will be randomly assigned in a 4:1 fashion to receive a single dose of monovalent vaccine or placebo by intranasal spray. This study will be conducted at multiple sites in the United States. Randomization will be stratified by site. Each subject will receive one dose of investigational product on Study Day 1. The duration of study participation for each subject is the time from receipt of investigational product through 180 days after receipt of investigational product. To summarize the primary safety phase data (Study Days 1-8), the study will be unblinded to the analysis team at MedImmune after all data through at least Study Day 8 are locked.