Study of Quadrivalent Influenza Vaccine Among Children

The aim of the study is to evaluate a prototype quadrivalent influenza vaccine (QIV), the licensed 2010-2011 trivalent influenza vaccine (TIV) containing the primary B strain (B1), and the investigational TIV containing the alternate B (B2) strain in children. Primary Objective: To demonstrate non-inferiority of antibody responses to QIV compared with licensed 2010-2011 TIV (containing the primary B strain) and investigational TIV (containing the alternate B strain) as assessed by geometric mean titer (GMT) ratios for each of the four virus strains separately among children aged 6 months to less than 9 years of age Secondary Objective: To demonstrate superiority of antibody responses to each B strain in QIV compared with antibody titers following vaccination with the TIV that does not contain the corresponding B strain, as assessed by GMT ratios and seroconversion rates. Observational Objective: To describe the safety profile of QIV among subjects 6 months to less than 9 years of age, as assessed by solicited injection site and systemic adverse events (AEs) collected for 7 days post-vaccination, unsolicited adverse events collected from 21 days post-vaccination, and adverse events of special interest and serious adverse events (SAEs) collected from Visit 1 to Visit 2.