Influenza A virus H7N9 vaccine (Novavax)

This is a randomized, observer-blinded, placebo-controlled trial in adults ≥18 years old. Randomization will be stratified by age (18 to 49 years and ≥50 years) and by prior influenza immunization within the past three months. Proportions of subjects in the various strata will not be pre-specified; rather, the goal will be to achieve an approximately equal distribution of subjects with these characteristics across the various treatment groups.
Treatments will comprise two identical IM doses at a 21-day interval (Day 0 and Day 21), in alternate deltoids. For each subject, study follow-up will span approximately 385 days total, or approximately 13 months from the first dose.