The purpose of this study is to evaluate consistency, immunogenicity and safety of live attenuated varicella vaccines manufactured at commercialized scale in aged 1-3 years children.

The study is a single-center, double-blind, randomized, bridging clinical trial. The purpose of this study is to evaluate the consistency between each two lots of live attenuated varicella vaccines, to evaluate the non-inferiority of the immunogenicity of live attenuated varicella vaccines manufactured at commercialized scale compared to trial-scale, and to evaluate the safety of live attenuated varicella vaccines. 1197 healthy Chinese children aged 1 to 3 years old were randomly assigned into four groups in the ratio 2:2:2:1. Children in the first three groups were administered with one dose of live attenuated varicella vaccines manufactured at commercialized scale, and children in the last group were administered with one dose of live attenuated varicella vaccines manufactured at trial-scale .

Inclusion Criteria:

• Healthy volunteer between 1-3 years old;
• legal identity;
• Guardian(s) of the volunteer should be capable of understanding the written - consent form, and such form should be signed before the children being included into this study.

Exclusion Criteria:

• Prior vaccination with varicella vaccine or with history of varicella infection;
• Axillaty temperature > 37.0 °C before vaccination;
• History of allergy to any vaccine or vaccine ingredient, or serious adverse reaction(s) to vaccination, such as urticaria, difficulty in breathing, angioneurotic edema, abdominal pain, etc;
• Epilepsy (except febrile seizures), history of seizures or convulsions, a family history of mental illness, autoimmune disease, or immunodeficiency;
• Severe malnutrition, congenital malformation, developmental disorders, or serious chronic diseases;
• Acute disease or acute stage of chronic disease within 7 days prior to study entry;
• Receipt of any blood product, immunosuppressant, hormone, other investigational medicine(s) within 30 days prior to study entry;
• Receipt of any live attenuated vaccine within 1 month prior to study entry, or receipt of any subunit vaccine or inactivated vaccine within 7 days prior to study entry;
• Any significant abnormity of heart, lung, liver, spleen, lymph nodes, or pharynx;
• Based on the judgment of investigator(s), there was any condition indicating that the subject should be excluded.