Meningococcal Group A and C Conjugate Vaccine (Chengda Bio)

Phase I: To evaluate the safety of group A and group C meningococcal polysaccharide conjugate vaccine in people aged 2 months (60-89 days) and above, and to provide a basis for the conduct of Phase III clinical trials. Phase III: Main objectives: (1) To compare with the control vaccine, to evaluate whether the group A and group C antibody seroconversion rate of the group A and group C meningococcal polysaccharide conjugate vaccine trial group is non-inferior to that of the control group; (2) To evaluate the safety of group A and group C meningococcal conjugate vaccine compared with the control vaccine.