A Clinical Trial of the ACYW135 Group Meningococcal Polysaccharide-Conjugated Vaccine (CRM197 Vector)

This study included 180 trial participants who had previously taken part in the Phase IIIb clinical trial of the ACYW135 group meningococcal polysaccharide-conjugated vaccine (CRM197 carrier) for children aged 4-6 years (Protocol No.: CTP-MCVF-002) and had completed blood sample collection at 90 and 180 days post-vaccination; there were 90 participants in each of the treatment and control groups. All trial participants were required to provide 3.0-4.0 mL of blood samples for immunopersistence assessment at 3 and 5 years post-vaccination, respectively.

Inclusion Criteria: * Individuals who previously participated in the Phase IIIb clinical trial of the ACYW135 group meningococcal polysaccharide-conjugated vaccine (CRM197 carrier) for children aged 4-6 years (Protocol No.: CTP-MCVF-002) and were included in both the IPS1 and IPS2 analysis sets * Willing to provide identification documents * Willing to provide informed consent, voluntarily sign the informed consent form, and comply with the requirements of the clinical study protocol * The interval since completion of the vaccination series must be at least 3 years Exclusion Criteria: * Received another meningococcal vaccine after completion of the CTP-MCVF-002 trial * Has thrombocytopenia, any coagulation disorder, or is currently receiving anticoagulant therapy * Has a history of meningitis since the end of the CTP-MCVF-002 trial * Other conditions deemed by the investigator to make the subject ineligible for this clinical study