Five-year Immune Persistence Study of Inactivated Enterovirus Type 71 (EV71) Vaccine

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the 5-year Immune Persistence of Inactivated Enterovirus Type 71 (EV71) Vaccine manufactured by Sinovac (Beijing) Biotech Co., Ltd.

Detailed Description
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The phase III, efficacy trial of inactivated vaccine (vero cell) against EV71 has completed on March 2013 in China,and a follow up study for phase III clinical trial has completed on March 2014. On the basis of phase III, this study is the Phase IV, open-labelled research, in order to evaluate the 5-year immune persistence of EV71 vaccine.

Official Title
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Phase IV, Open-labelled, Five-year Immune Persistence Study of Inactivated Enterovirus Type 71 (EV71) Vaccine

Conditions
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Hand, Foot and Mouth Disease

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: In the prior phase III clinical trial, 10077 subjects in three counties (Ganyu, Sheyang and Taixing ) were enrolled ( Experimental group: 5044; Control group: 5043 ), with 1293 of them in immunogenicity subgroup (Experimental group: 648; Control group: 645). In Sheyang county, 3351 subjects were enrolled (Experimental group: 1676 ; Control group :1675) , with 435 of them in immunogenicity subgroup (Experimental group: 418 ; Control group :418). The subjects in Sheyang immunogenicity subgroup with the following conditions were included in this study: Guardian(s) of the volunteer should be capable of understanding the written consent form, and such form should be signed before the infant being included into this study Received at least one injection of EV71 vaccine or the placebo in the phase III clinical trial Finished the blood sampling 64 months after the vaccination Exclusion Criteria: Received extra EV71 vaccination after the phase III clinical trial Refused to join the study

Ages Eligible for Study
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Minimum Age: 6 Months
Maximum Age: 35 Months

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| EV71 vaccine group<br>The group which received two doses EV71 vaccine (400U/0.5ml) on day 0,28 in phase III clinical trial. | |
| Placebo group<br>The group which received two doses placebo (0U/0.5ml) on day 0,28 in phase III clinical trial. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The seropositive rate of EV71 neutralizing antibody-1 | Calculated based on the cutoff value of 1:8 | 5 years (64 months) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The seropositive rate of EV71 neutralizing antibody-2 | Calculated based on the cutoff value of 1:16 | 5 years (64 months) | 
| The seropositive rate of EV71 neutralizing antibody-3 | Calculated based on the cutoff value of 1:32 | 5 years (64 months) | 
| The GMT of EV71 neutralizing antibody | The GMT of EV71 neutralizing antibody 64 months after the first dose injection | 5 years (64 months) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Inactivated Enterovirus Type 71 (EV71) Vaccine, 5-year Immune Persistence