To evaluate Immunogenicity and Safety of Adjuvant and Adjuvant-Free Meningococcal Groups A and C and Haemophilus b Conjugate Vaccine in Infants 2 to 5 Months of Age.

Primary objective:

• To demonstrate the non-inferiority of the antibody responses to meningococcal serogroups A, C and Haemophilus influenzae type b following the administration of adjuvant-free MenAC-Hib conjugate vaccine compared to those observed following the administration of adjuvant MenAC-Hib conjugate vaccine.
• To describe the safety profile of adjuvant-free MenAC-Hib conjugate vaccine compared to that of adjuvant MenAC-Hib conjugate vaccine.

Secondary objective:

•To compare the antibody level of meningococcal serogroups A, C and Haemophilus influenzae type b following the administration of adjuvant-free MenAC-Hib conjugate vaccine to those observed following the administration of adjuvant MenAC-Hib conjugate vaccine.

Inclusion Criteria:

• Health infants aged 2 to 5 months.
• Legal guardian has signed written informed consent.
• Guardian may finish the whole visit in the judgment of investigator.
• 2-5 months health infants who haven't immuned with any Meningococcal A and C Conjugate Vaccine or Haemophilus b Conjugate Vaccine.
• Subject who did't vaccinated with any live vaccine within 14 days or inactivated vaccine within 10 days before vaccination.

Exclusion Criteria:

• Fever, body temperature ≥37.1℃.
• History of severe allergic reaction that needs medical intervention including throat swelling, dyspnea, hypotension or shock; History of allergic reaction to vaccine or to any of the vaccine components especially to tetanus toxoid or history of other severe adverse reaction to vaccine.
• Clear diagnosis of thrombocytopenia or history of other coagulation disorders that may cause contraindications of intramuscular injection.
• Subject with history of abnormal labor, asphyxia rescue history,congenital malformations,eccyliosis or severe chronic disease.
• Severe cardiovascular or liver and kidney disease, active tuberculosis and HIV infection.
• Subject with encephalopathy, uncontrolled epilepsy and other progressive nervous system disease.
• Subject suffer from acute disease, severe chronic disease, acute episode of chronic disease and febrile illness (temperature ≥ 38°C) within 3 days.
• Any condition that, in the judgment of investigator, subject is not suitable for participation in this clinical trial.