A Blind, Randomized and Controlled Study of Live Attenuated Varicella Vaccines

Inclusion Criteria: * Healthy volunteer between 1 - 12 years old; * Proven legal identity; * Guardian(s) of the volunteer and/or volunteers themselves should be capable of understanding the written consent form, and such form should be signed before the volunteer being included into this study; Exclusion Criteria: * Prior vaccination with varicella vaccine or with history of varicella zoster virus (VZV) infection; * Axillaty temperature \> 37.0 °C; * 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; * History of epilepsy, seizures or convulsions, or 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 of the following products: 1. Any subunit vaccine or inactivated vaccine within 7 days prior to study entry; 2. Any live attenuated vaccine within 1 month prior to study entry; 3. Any blood product, immunosuppressant, hormone, or other investigational medicine(s) within 30 days prior to study entry; * Any significant abnormity of heart, lung, skin, or pharynx; * Any other factor that suggesting the volunteer is unsuitable for this study based on the opinions of investigators;