This a randomized, blind, controlled clinical trial of live attenuated varicella vaccines manufactured by Sinovac (Dalian) Vaccine Technology Co., Ltd .The purpose of this study is to evaluate the immunogenicity of a two doses vaccination of investigational vaccine with 0,28 day, 0,42 day and 0,56 day immunization schedule in population aged ≥13 years old.

This study is a randomized, blind, controlled phase # clinical trial in population aged ≥13 years old. The experimental vaccine will be manufactured by Sinovac (Dalian) Vaccine Technology Co., Ltd.A total of 2400 subjects aged 13 years and older will be enrolled with1200 subjects in 13 ~ 17 years old group and1200 subjects in 18 years and older group.960 subjects in each age group will be randomly divided into experimental group and control group according to 1:1 ratio,and subjects will receive two doses of vaccine with the immunization course of 0,28 days, 0,42 days or 0,56 days. An additional 240 subjects in each age group will be randomly divided into experimental group and control group according to 2:1 ratio to receive two doses of the experimental vaccine or placebo with the immunization course of 0, 70 days.In addition,400 subjects including 320 people of experimental group in different immunization course according to the difference of age and 80 people of placebo group according to the difference of age will be selected to collect blood about 3ml each time to evaluate immunity persistence of live attenuated varicella vaccines at 3 and 5 years after the whole immunization.

Inclusion Criteria:

• Healthy population aged 13 years and above;
• Proven legal identity;
• The subjects and/or guardians can understand and voluntarily sign the informed consent form (For subjects aged 13-17 years, both subjects and guardians need to sign the informed consent form);

Exclusion Criteria:

• History of chickenpox or shingles;
• Axillary temperature >37.0°C;
• Already pregnant (including a positive urine pregnancy test) or are breastfeeding, planning to get pregnant within 6 months;
• 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;
• Autoimmune disease or immunodeficiency / immunosuppression;
• Severe chronic diseases, severe cardiovascular diseases,hypertension(adult field measurement: SBP ≥140mmHg or diastolic blood pressure ≥90mmHg)and diabetes that cannot be controlled by drugs, liver or kidney diseases;
• Family history of psychosis,severe neurological disease (epilepsy, convulsions or convulsions) or mental illness;
• Thyroid disease or history of thyroidectomy, asplenia, functional asplenia,asplenia or splenectomy resulting from any condition;
• 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) in the past 6 months;
• History of alcohol or drug abuse;
• Receipt of blood products within in the past 3 months;
• Participating in other drug/vaccine clinical trial;
• 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;
• According to the investigator's judgment, the subject has any other factors that are not suitable for participating in the clinical trial.