An Immunity Persistence Study of Booster Dose of Live Attenuated Varicella Vaccine

Launched by SINOVAC (DALIAN) VACCINE TECHNOLOGY CO., LTD. · Jun 26, 2024

Keywords

ClinConnect Summary

This study is checking how long protection from a live varicella (chickenpox) vaccine booster lasts. It’s an open‑label, single‑group trial (no comparison group) and is focused on immunity that remains 6 years and 10 years after the booster. Researchers will measure two things: the seropositive rate, which is the percentage of participants who still have detectable antibodies to varicella zoster virus, and the GMT, which is the average level of those antibodies. The vaccine studied is a live attenuated varicella vaccine made by Sinovac, and the study is being done in Zhengzhou, China. About 3 mL of blood will be collected at the 6‑ and 10‑year marks to test the antibodies.

Who can join? The study is for children and teens who previously took part in the phase 3 trial of the varicella vaccine and are now roughly 8 to 16 years old, healthy, and able for consent by a parent or guardian. Exclusion criteria include a history of chickenpox or shingles, or a varicella vaccine since the phase 3 trial, as well as other standard eligibility checks set by the investigators. Participants will have blood draws at the 6‑ and 10‑year follow‑ups to assess their immune durability. The trial is being conducted under Sinovac’s oversight in China, with no data sharing of individual participant information.

Gender

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Eligibility criteria

• Inclusion Criteria:
• • Subjects in PPS of previous phase Ⅲ clinical trial of varicella vaccine;
• • The subjects and/or guardian can understand and voluntarily sign the informed consent form;
• • Proven legal identity.
• Exclusion Criteria:
• • Beyond the blood collection window period;
• • History of varicella or shingles;
• • History of varicella vaccination 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.