An Immunity Persistence Study of Live Attenuated Varicella Vaccine

Study Overview
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Brief Summary
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This an open phase Ⅳ clinical trial of live attenuated varicella vaccines manufactured by Sinovac (Dalian) Vaccine Technology Co., Ltd .The purpose of this study is to evaluate the immunity persistence of live attenuated varicella vaccine at 5 and 8 years after primary immunization with live attenuated varicella vaccine.

Detailed Description
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This study is an open phase Ⅳ clinical trial in subjects who enrolled in the clinical trial and included in the immunogenicity subgroup PPS set from August to September 2016 .The experimental vaccine and placebo (Freeze Dired Dilution) were manufactured by Sinovac (Dalian) Vaccine Technology Co., Ltd.A total of 703 subjects will be enrolled including 349 subjects in experimental group and 354 subjects in control group .And 3.0-3.5ml of venous blood was collected from all subjects at 5 and 8 years after primary immunization, and the serum was separated for varicella antibody detection. The window period of blood collection was six months.

Official Title
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An Open Clinical Trial to Evaluate the Immunity Persistence of Live Attenuated Varicella Vaccine at 5 and 8 Years After Primary Immunization With Live Attenuated Varicella Vaccine

Conditions
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Varicella

Intervention / Treatment
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* Biological: Investigational Live Attenuated Varicella Vaccine
* Biological: Placebo (Freeze Dired Dilution)


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 1 Year
Maximum Age: 17 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Experimental Group<br>349 subjects who enrolled in the experimental group of clinical trial and included in the immunogenicity subgroup PPS set from August to September 2016 will be collected venous blood 3.0 3.5ml at 5 and 8 years after primary immunization. | Biological: Investigational Live Attenuated Varicella Vaccine<br>* The live attenuated varicella vaccine was manufactured by Sinovac (Dalian) Vaccine Technology Co., Ltd. Live attenuated varicella-virus in 0·5 mL injection water with sucrose,sodium glutamate,sodium chloride,potassium chloride, sodium dihydrogen phosphate, potassium dihydrogen phosphate per injection.<br>|
| Placebo Comparator: Control Group<br>354 subjects who enrolled in the control group of clinical trial and included in the immunogenicity subgroup PPS set from August to September 2016 will be collected venous blood 3.0 3.5ml at 5 and 8 years after primary immunization. | Biological: Placebo (Freeze Dired Dilution)<br>* The placebo (freeze dired dilution) was manufactured by Sinovac (Dalian) Vaccine Technology Co., Ltd. and contained no active ingredient.It was 0·5 mL injection water with sucrose,sodium glutamate,sodium chloride,potassium chloride and phosphate.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Immunogenicity index-seropositive rates of varicella antibody | The seropositive rates of varicella antibody in 5 years after primary immunization with varicella vaccine | 5 years after primary immunization | 
| Immunogenicity index-GMT of varicella antibody | GMT of varicella antibody in 5 years after primary immunization with varicella vaccine | 5 years after primary immunization | 
| Immunogenicity index-the seropositive rates of varicella antibody | The seropositive rates of varicella antibody in 8 years after primary immunization with varicella vaccine | 8 years after primary immunization | 
| Immunogenicity index-the GMT of varicella antibody | GMT of varicella antibody in 8 years after primary immunization with varicella | 8 years after primary immunization |