AC group meningococcal (combined) Haemophilus influenzae type b (combined) vaccine(Beijing Luzhu Biopharmaceutical Co., Ltd.)

(1) To evaluate the immune persistence of freeze-dried AChib meningococcal conjugate vaccine in infants aged 6-11 months 1-2 years after primary immunization, as well as the immunogenicity and safety after one booster immunization; (2) To evaluate the immunogenicity and safety of this product for sequential vaccination in infants aged 6-11 months 1-2 years after primary immunization with group A and group C meningococcal polysaccharide conjugate vaccine and type b Haemophilus influenzae conjugate vaccine.

(1) To demonstrate that the antibody seroconversion rate of the non-adjuvanted AChib combined meningococcal vaccine is non-inferior to that of the marketed adjuvanted AChib combined meningococcal vaccine 30 days after three doses in 0, 1, and 2 months in infants aged 2 and 3 months; (2) To evaluate the safety of the non-adjuvanted AChib combined meningococcal vaccine compared with the adjuvanted AChib combined meningococcal vaccine.