An Immunity Persistence Study of Live Attenuated Varicella Vaccine

Launched by SINOVAC (DALIAN) VACCINE TECHNOLOGY CO., LTD. · Oct 14, 2021

Keywords

ClinConnect Summary

This is a Phase 4 study in China to see how long protection lasts after a live, weakened varicella (chickenpox) vaccine made by Sinovac. The study compares an Experimental Group that gets the varicella vaccine with a Control Group that receives a placebo (a harmless injection with no active vaccine). About 703 children and teens who were part of an earlier trial are enrolled, and researchers will measure the immune response by taking blood samples about 5 and 8 years after vaccination. The main goals are to find out what portion of participants still have varicella antibodies and what the average antibody level is at those time points.

Who can participate: children and teens aged 1 to 17 who were in the immunogenicity subgroup of the previous Phase III trial, are healthy, and have not had chickenpox or shingles or received a varicella vaccine since that trial. They must understand and sign informed consent. The study is conducted at two centers in Henan, China, and enrollment is by invitation. Blood samples of about 3.0–3.5 mL are collected at the 5- and 8-year marks (within a six‑month window). The trial is sponsored by Sinovac, and results are not yet available.

Gender

ALL

Eligibility criteria

• 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.