Sample size and test grouping:~In this study, a total of 360 subjects were enrolled in a self-controlled trial design.~In this study, 360 subjects aged 3 to 8 years old were enrolled. According to their previous influenza vaccine vaccination status, they were assigned to experimental group 1 (no previous influenza vaccine), experimental group 2 (one dose of influenza vaccine previously) and experimental group 3 (two or more doses of influenza vaccine previously), with 120 cases in each experimental group.~All subjects received one dose of tetravalent influenza virus lysis vaccine on day 0,28 for immunogenicity and safety observation.~The enrollment sequence of this study is divided into two stages:~First stage: group 1, group 2 and group 3 into the group of 20 people, each agent 1 test vaccine respectively, collecting agent 1 test vaccine adverse event, within 7 days after 8 days after 1 dose diary collection card security assessment, confirm safe (not to suspend/terminate the test standard), can be on to the next stage into the group; The second dose of the trial vaccine was administered, adverse events were collected within 7 days after the second dose of the trial vaccine, diary cards were collected for safety assessment 8 days after the second dose, and the next phase of the second dose of vaccine could be administered after the safety was confirmed (criteria for suspension/termination of the trial were not met);~The second stage: The remaining 100 subjects in experimental groups 1, 2 and 3 were inoculated with the first and second doses of experimental vaccine.~Blood collection procedure:~About 4.0ml of venous blood was collected from all subjects before each dose and 30 days after the second dose.
To explore the immunogenicity and safety of quadrivalent split influenza virus vaccine in children aged 3-8 years with two doses and one dose. This clinical trial was designed as a self-controlled trial to observe the immunogenicity and safety. This study was an exploratory study.~Sample size and test grouping:~In this study, a total of 360 subjects were enrolled in a self-controlled trial design.~In this study, 360 subjects aged 3 to 8 years old were enrolled. According to their previous influenza vaccine vaccination status, they were assigned to experimental group 1 (no previous influenza vaccine), experimental group 2 (one dose of influenza vaccine previously) and experimental group 3 (two or more doses of influenza vaccine previously), with 120 cases in each experimental group.~All subjects received one dose of tetravalent influenza virus lysis vaccine on day 0,28 for immunogenicity and safety observation.