The purpose of this study is to evaluate immunogenicity and safety of S.flexneriza-S.sonnei Bivalent Conjugate Vaccine in healthy volunteers aged from 3 months to 5 years old.

Inclusion Criteria:

• Health infants and children aged from 3 months to 5 years old.
• Subject or legal representative who consent and has signed written informed consent.
• Subject and parent/guardian who is able to comply with all study procedures.
• Subject who did't receive blood products within 30 days ,immune with any live vaccine within 14 days and inactivated vaccine within 7 days before vaccination.
• Subject who haven't immuned with diarrhea vaccination,3-11 months health infants who haven't immuned with Haemophilus b Conjugate vaccination,or had a history of Hib vaccination before the age of 1 but no history of vaccination after 1 year of age,and the interval between the day of the enrollment and the previous dose is more than one month.
• Axillary temperature ≤37.0 ℃.

Exclusion Criteria:

• Febrile illness (temperature ≥ 38°C) in the 3 days or in the acute phase of the disease / active period.
• Subject who have symptoms such as diarrhea, abdominal pain, and pus and bloody stools in the past 3 days.
• Subject who are allergic to tetanus toxoid.
• Allergic history after vaccination.
• Immunodeficiency diseases patients (such as perianal abscess suggests that there may be immunodeficiency in infants and young children) who administered with immunosuppressive agents (≥14 days).
• Subject who are suffering from serious chronic diseases, cardiovascular disease,liver or kidney disease.
• Subject with congenital malformations, drug allergies, convulsions, epilepsy, history of craniocerebral trauma, encephalopathy and psychosis, or family history.
• Subject who diagnosis of thrombocytopenia or other history of coagulopathy may cause intramuscular contraindication.
• Children with abnormal labor（pregnancy week<37w,>42w）,birth weight (<2500g,>4000g), asphyxia rescue history(Only applicable to 3-5 months old group).
• Subject who plan to participate in or is in any other drug clinical trial.
• Any condition that, in the judgment of investigator, may affect trial assessment.