Inclusion Criteria:  Subjects in PPS immunogenicity subgroup of phase Ⅲ clinical trial of protective effect of varicella vaccine; The subject and/or guardian can understand and voluntarily sign the informed consent form; Proven legal identity.  Exclusion Criteria:  History of chickenpox or shingles; History of varicella vaccination since phase Ⅲ clinical trial; Autoimmune disease or immunodeficiency / immunosuppression; History of immunosuppressive therapy since phase Ⅲ clinical trial; According to the investigator's judgment, the subject has any other factors that are not suitable for participating in the clinical trial.