Study to Evaluate Immunogenicity, Safety and Tolerability of Adjuvanted and Non-Adjuvanted H2N3 Influenza Vaccines in Adults

This Phase 1, randomized, observer-blind, dose-ranging clinical study is evaluating 6 different formulations of MF59-adjuvanted and non-adjuvanted H2N3 influenza vaccine. Approximately 600 healthy adult subjects are to be randomized into 1 of 6 possible treatment groups with 100 subjects per group, stratified by age group (born after or before 1968). Each subject will receive an influenza vaccine injection on Day 1 and Day 22. Subjects will be followed up for approximately 12 months after the second vaccine injection. The primary immunogenicity analysis is based on the Day 1, Day 8, Day 22, Day 29, and Day 43 serology data. The primary safety analysis is based on solicited local and systemic adverse events (AEs) reported within 10 days after each vaccination, unsolicited AEs reported within 3 weeks after each vaccination, and serious AEs (SAEs), medically attended AEs (MAAEs), AEs leading to withdrawal from the study, and AEs of special interest (AESIs) reported throughout the study.