Evaluation of the Safety and Immunogenicity of Hepatitis A Vaccine

Subjects will be recruited and divided into 3 groups:

1. Hepatitis A（Live）Vaccine，Freeze-dried produced by Changchun Institute of Biological Products Co., Ltd
2. Hepatitis A（Live）Vaccine，Freeze-dried produced by Zhejiang Pukang Biotechnology Co., Ltd., and
3. Hepatitis A（Live）Vaccine，Freeze-dried produced by Institute of Medical Biology, Chinese Academy of Medical Sciences.

After immunization, the immunogenicity and safety of three different manufacturers will be compared and the data will be analyzed.

To evaluate the safety and immunogenicity of Hepatitis A (Live) Vaccine, Freeze-dried produced by Changchhun Institute of Biological Products Co., Ltd, we design this randomized, parallel controlled study. 450 subjects are divided into 3 groups, including 1 experimental group and 2 control groups (Research Group 1, 2, and 3), each group assigned 150 subjects respectively.

All subjects are aged 18-24 months old.

150 subjects from Research Group 1 will be administrated with one dose of Hepatitis A (Live) Vaccine, Freeze-dried produced by Changchhun Institute of Biological Products Co., Ltd. Blood samples are collected before vaccination and one month (30 days) later.

150 subjects from Research Group 2 will be administrated with one dose of Hepatitis A（Live）Vaccine，Freeze-dried produced by Zhejiang Pukang Biotechnology Co., Ltd. Blood samples are collected before vaccination and one month (30 days) later.

150 subjects from Research Group 3 will be administrated with one dose of Hepatitis A (Live) Vaccine, Freeze-dried produced by Institute of Medical Biology, Chinese Academy of Medical Sciences. Blood samples are collected before vaccination and one month (30 days) later.

To evaluate the immunogenicity, we will detect and compare the seroconversion rates, and antibody geometric mean concentrations. The safety of all groups will be monitored as well.

Eligibility Criteria:
Inclusion Criteria:

1. subjects aged from 18 to 24 months old at the date of recruitment;
2. with informed consent signed by parent(s) or guardians;
3. parent(s) or guardians are able to attend all planned clinical appointments and obey and follow all study instructions;
4. subjects have not been vaccinated with any type of Hepatitis A vaccines;
5. subjects have no Hepatitis A disease and contraindication of vaccination;
6. subjects did not receive any vaccines within 14 days;
7. before joining this trial, subjects must be qualified and passed their medical history and clinical examinations, and axillary's temperature must be ≤37℃.

Exclusion Criteria:

1. Subjects with history of allergy, convulsion, epilepsy, encephalopathy and psychosis or family history;
2. Allergic to any ingredient of vaccine or with allergy history to any vaccine;
3. Patients with immunodeficiency, in process of cancer treatment, immunosuppressive therapy (oral steroids) or HIV induced hypoimmunity, or in close contact with any family members who has congenital immune diseases;
4. Receive non-specific immunoglobulin within 1 month before recruitment;
5. Subjects with acute febrile diseases with body temperature \> 37.0 ℃ or infectious diseases;
6. Subjects with a history of thrombocytopenia or other coagulation disorders that may be contraindicated for hypodermic injection;
7. With known or suspected concurrent diseases include respiratory disease, acute infection or active chronic disease;
8. With severe cardiovascular diseases (Pulmonary heart disease, Pulmonary edema, hypertension cannot be controlled to normal range by drugs), liver and kidney diseases and diabetic complications;
9. Various infectious, suppurative or allergic dermatitis;
10. Other circumstances judged by investigators that are not suitable for this clinical trial.