Phase Ⅲ Trial of Group ACYW135 Meningococcal Conjugate Vaccine in Children Aged 12-23 Months

The goal of this clinical trial is to evaluate the immunogenicity and safety of an investigational group ACYW135 Meningococcal conjugate vaccine in healthy children aged 12 to 23 months. The main questions it aims to answer are: Is the immune response induced by the investigational vaccine non-inferior to that of the licensed control vaccine? What safety profile does the investigational vaccine have in this pediatric population? Researchers will compare the investigational vaccine group with the active comparator group (licensed ACYW135 meningococcal conjugate vaccine (CRM197 carrier), CanSinoBIO; hereinafter referred to as CanSinoBIO MCV-ACYW) to determine if the new vaccine provides comparable immune protection with an acceptable safety profile. Participants will: Receive two doses of either the investigational vaccine or the control vaccine according to a 0,1-month schedule; Be observed for 30 minutes after each dose for immediate adverse reactions; Have solicited local and systemic adverse events recorded for 7 days after each dose using diary cards; Have unsolicited adverse events recorded for 30 days after each dose using diary cards; Be monitored for serious adverse events for at least 6 months after completion of the primary immunization series; A total of 1040 participants will be enrolled and randomly assigned in a 1:1 ratio to either the investigational group or the control group.