Correlation of Protection Against Varicella in an Exploratory Study

This study consists of two parts. Part 1 is a retrospective cohort study and part 2 is a prospective cohort study. In Part 1 ,the scaled logit model was used to assess the correlation between varicella-zoster virus (VZV) antibody titers using fluorescent-antibody-to-membrane-antigen assay (FAMA) 30 days after varicella vaccine immunization and the risk of subsequent varicella breakout/disease , to determine the protective threshold for achieving FAMA antibodies. Part 2 was to validate the model in part 1.

Study Overview

• Status: Not yet recruiting
• Conditions: Varicella
• Intervention / Treatment: Biological: Varicella vaccine

Detailed Description

Part 1 was based on a previous Phase Ⅲ, randomized, placebo-controlled clinical trial (NCT02981836) conducted from 2016 to 2017. The analysis data of part 1 was from historical serum, historical varicella cases and additional one year case monitoring conducted as an extension of the Phase III study.

Part 2 was conducted based on close contacts of varicella cases. All close contacts without varicella symptoms will be recruited and followed up for 14 days to monitor the occurrence of the varicella cases. Part 2 aimed to compare the differences of FAMA antibody titers in varicella breakthrough cases, non-breakthrough cases, and non-cases at the time of exposure to validate/calibrate the model established in part 1.

• Study Type: Observational
• Enrollment (Estimated): 400

Contacts and Locations

• Study Contact: Name: Xiaoqiang Liu; Phone Number: 15911568282; Email: lxq7611@126.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

There was no inclusion/exclusion criteria in the retrospective cohort study. The inclusion/exclusion criteria were only applicable in the prospective cohort.

Subjects in the retrospective cohort study aged 8-20 years were from a previous phase Ⅲ study. There is no limit to the sample size of the retrospective cohort, which is based on the number of final follow-up.

Description

Inclusion Criteria:

• 1-12 years children who were the siblings or children of the indicator varicella cases, or the deskmates/roommates of the indicator varicella cases;
• Having close contacts with the indicator varicella cases at least 2 days during the period from 5 days before the onset and 2 days after the onset;
• Without varicella vaccination history or having varicella vaccination history (the last dose of varicella was manufacured by Sinovac, with an interval of >30 days before enrollment)
• Subjects/legal guardian can understand and sign the informed consent;
• Being able to provide legal proof of identity.

Exclusion Criteria:

• Without varicella history;
• Body temperature ≥37.0℃ on the day of enrollment, or skin rash on the head, torso, and limbs;
• Having any confirmed or suspected immunodeficiency disorder, including tumor patients undergoing chemotherapy, human immunodeficiency virus (HIV) infection, continuous use of steroid hormones for more than 30 days (prednisone equivalent ≥2mg/kg days in children), or having other immunosuppressive disorder as determined by the clinician;
• The investigators considered that participation in this study was not appropriate for various other reasons.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Vaccination group; The last dose of varicella vaccine given 30 days before enrollment was manufacture by Sinovac (Dalian) Vaccine Technology Co. LTD.,(Sinovac).	Biological: Varicella vaccine; lyophilized powder,subcutaneous injection
Non-vaccination group; Without varicella vaccine history

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Retrospective cohort: Varicella confirmed case	Varicella confirmed case during an additional year follow-up period (pooled with varicella confirmed case from previous phase Ⅲ study)	one year after enrollment
Retrospective cohort: Varicella antibody titer	Varicella antibody titer on Day 30 after vaccination (historical serum)	on Day 30 after vaccination
Prospective cohort: Varicella confirmed case	Varicella confirmed case during the 14-day follow-up period	Within 14 days after enrollment
Prospective cohort: Varicella antibody titer	Varicella antibody titer on exposure	Enrollment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prospective cohort: Varicella antibody titer	Varicella antibody titer in the acute period of varicella confirmed case	Within 3 days after eruption
Prospective cohort: Varicella antibody titer	Varicella antibody titer in the convalescent period of varicella confirmed case	Within 14-21 days after eruption

Collaborators and Investigators

• Sponsor: Sinovac (Dalian) Vaccine Technology Co., Ltd.
• Investigators: Principal Investigator: Xiaoqiang Liu, Yunnan Provincial Center for Disease Control and Prevention; Principal Investigator: Zhiqiang Xie, Henan Provincial Center for Disease Control and Prevention

Study record dates

Study Major Dates

• Study Start (Estimated): October 10, 2025
• Primary Completion (Estimated): May 10, 2027
• Study Completion (Estimated): October 10, 2028

Study Registration Dates

• First Submitted: June 25, 2024
• First Submitted That Met QC Criteria: June 25, 2024
• First Posted (Actual): July 1, 2024

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 23, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Varicella Zoster Virus Infection; Infections; Virus Diseases; DNA Virus Infections; Herpesviridae Infections; Herpes Zoster; Chickenpox
• Other Study ID Numbers: PRO-VZV-4007

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No