Protective Effect, Safety and Immunogenicity of Live Attenuated Varicella Vaccine in Anhui Province

Study 1: Inclusion criteria for a protective effect study of varicella vaccine: * Healthy children aged 1-12 years without a history of varicella; * The subjects and/or guardians can understand and voluntarily sign the informed consent form (For subjects aged 8 years and above, both subjects and guardians need to sign the informed consent form); Study 2: Inclusion criteria for immunogenicity and safety evaluation of varicella vaccine: * Healthy children aged 1-12 years without a history of varicella; * The subjects and/or guardians can understand and voluntarily sign the informed consent form (For subjects aged 8 years and above, both subjects and guardians need to sign the informed consent form); * The subjects and their guardians voluntarily participate in the study and are able to follow all study procedures; * Proven legal identity. Study 3: Inclusion criteria for safety evaluation of mass vaccination of varicella vaccine : * Healthy children aged 1-12 years without a history of varicella; * The subjects and/or guardians can understand and voluntarily sign the informed consent form (For subjects aged 8 years and above, both subjects and guardians need to sign the informed consent form); * The subjects and their guardians voluntarily participate in the study and are able to follow all study procedures; * Proven legal identity; * Subjects'guardians can fill in adverse events using mobile apps; Study 4: Inclusion criteria for etiological study on the pathogenic strains of varicella cases: * Varicella cases among study 1 enrolled subjects who signed informed consent for biological samples collection. Exclusion Criteria: * Received two doses of varicella vaccine from other manufacturers(applied to study 1 exclusion criteria); * Received two doses of varicella vaccine; * History of severe allergic reactions to vaccines (e.g.acute anaphylaxis, angioneurotic edema, dyspnea, etc.); * Any confirmed or suspected immunodeficiency disease, including human immunodeficiency virus (HIV) infection; * Axillary temperature \>37.0°C; * Receipt of other investigational drugs in the past 30 days; * Receipt of attenuated live vaccines in the past 28 days; * Receipt of inactivated or subunit vaccines in the past 7 days; * According to the investigator's judgment, the subject has any other factors that are not suitable for participating in the clinical trial.