This study is a randomized and controlled Phase IV clinical trial.The purpose of this study is to evaluate the immunogenicity and safety of combined immunization with live attenuated varicella vaccine and inactivated hepatitis A vaccine in children aged 12-15 months.

This study is a randomized and controlled phase IV clinical trial in children aged 1 year old (12-15 months).The purpose of this study is to evaluate the immunogenicity and safety of live attenuated varicella vaccine co-administration with inactivated hepatitis A vaccine .The live attenuated varicella vaccine was manufactured by Sinovac (Dalian) Vaccine Technology Co., Ltd,the inactivated hepatitis A vaccine was manufactured by Sinovac Biotech Co., Ltd.A total of 450 subjects aged 1 year old (12-15 months) were be enrolled.Subjects were be randomly divided into 2 groups in a ratio of 1:1.Subjects in the combined immunization group received one dose of live attenuated varicella vaccine and the first dose inactivated hepatitis A vaccine on day 0 and the second dose of inactivated hepatitis A vaccine on day 180.Subjects in the Non-combined immunization group received one dose of live attenuated varicella vaccine on day 0,the first dose of inactivated hepatitis A vaccine on day 42 and the second dose of inactivated hepatitis A vaccine on day 222.

Inclusion Criteria:

• Healthy child aged 1 year old (12-15 months old);
• Proven legal identity;
• The subjects'guardians should be capable of understanding the informed consent form, and such form should be signed prior to enrolment.

Exclusion Criteria:

• History of vaccination of varicella vaccine or hepatitis A vaccine.
• Previous history of varicella infection or hepatitis A infection;
• History of asthma, history of allergy to the vaccine or vaccine components, or serious adverse reactions to the vaccine, such as urticaria, dyspnea, and angioedema;
• Congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc;
• Thyroid disease or history of thyroidectomy, asplenia,functional asplenia,asplenia or splenectomy resulting from any condition;
• Suffering from serious chronic diseases, serious cardiovascular diseases, liver and kidney diseases, malignant tumors, etc;
• Family history of psychosis,severe neurological disease (epilepsy, convulsions or convulsions) or mental illness;
• Diagnosed abnormal blood coagulation function (eg, lack of blood coagulation factors, blood coagulopathy, abnormal platelets) or obvious bruising or blood coagulation;
• Immunosuppressive therapy, cytotoxic therapy, inhaled corticosteroids(excluding allergic rhinitis corticosteroid spray therapy, acute noncomplicated dermatitis superficial corticosteroid therapy) within 6 months before enrollment;
• Receipt of blood products within the past 3 months;
• Receipt of other investigational vaccines or drugs within 28 days prior to receiving the investigational vaccine;
• Receipt of attenuated live vaccines in the past 28 days;
• Receipt of inactivated or subunit vaccines in the past 7 days;
• Onset of various acute or chronic diseases within 7 days prior to the study;
• Armpit temperature in subjects with fever prior to vaccination with the investigational vaccine. 37.4 ℃;
• According to the investigator's judgment, the subject has any other factors that are not suitable for participating in the clinical trial