A randomized, blind, positive vaccine control trial was designed.A total of 2550 subjects aged 6-35 months were randomly assigned to the low dose (0.25ml/ dose) group, the high dose (0.5ml/ dose) group and the control group in a ratio of 1:1:1. They were inoculated with 2 doses of quadrivalent influenza virus split vaccine (experimental vaccine or control vaccine) at 0 and 28 days of immunization program to observe the Immunogenicity and safety.~Immunogenicity observation Venous blood (2.5-3.0ml) was collected from all subjects before the first dose and 30 days after the full dose, and serum was separated for detection of Hemagglutination Inhibition antibodies against four influenza virus serotypes (H1N1, H3N2, B (V), B (Y)).~Safety observation All AE within 30 minutes of each dose, solicited adverse events at 0-7 days, non-solicited adverse events at 0-28 days (first dose) /30 days (second dose), and all serious adverse events from the first dose to 6 months after the full dose were collected.
A randomized, blind, positive vaccine control trial was designed.A total of 2550 subjects aged 6-35 months were randomly assigned to the low dose (0.25ml/ dose) group, the high dose (0.5ml/ dose) group and the control group in a ratio of 1:1:1. They were inoculated with 2 doses of quadrivalent influenza virus split vaccine (experimental vaccine or control vaccine) at 0 and 28 days of immunization program to observe the Immunogenicity and safety.