The study includes open-labelled phase I and randomized, double-blind, controlled phase III clinical trial. In the phase I, 20 healthy Chinese children aged 6-35 months were administered with two doses of QIV (7.5μg/0.25ml). In the phase Ⅲ clinical trial, 2320 children were assigned to QIV group, TIV (B/Victoria) group and TIV (B/Yamagata) group in a 2:1:1 ratio. All vaccines were manufactured by Sinovac Biotech Co., Ltd.
The purpose of this study is to evaluate the safety and immunogenicity of quadrivalent influenza vaccine in healthy children aged 6-35 months.