Influenza Vaccine (Split Virion), Inactivated, Quadrivalent (Toyouvax)

Primary objective: To evaluate the immunogenicity of the trial vaccine in people aged 3 years and above. Secondary objective: To evaluate the safety of the trial vaccine in people aged 3 years and above.

The primary objective is to preliminarily evaluate the safety and tolerability of the quadrivalent influenza virus split vaccine. The secondary objective is to explore the immunogenicity and safety of the two-dose immunization program of the quadrivalent influenza virus split vaccine in people aged 3-8 years. All subjects were observed for immediate reactions within 30 minutes after vaccination, systemic and local adverse events within 0-7 days, and adverse events within 0-28/30 days, and serious adverse events were reported 6 months after vaccination. HI antibodies were detected in the peripheral venous serum of the subjects before immunization and 30 days after the last immunization to evaluate the immunogenicity of the trial vaccine.