Long-Term Immunogenicity Study of Inactivated EV71 Vaccine in Children

Study Overview
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Brief Summary
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This study is designed to evaluate the long-term antibody titers of EV71 vaccine 4 and 5 years after first dose vaccination for subjects at the age of 2 to < 6 years , and 3 to 5 years after first dose vaccination for subjects at the age of 2 months to < 2 years

Detailed Description
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This is an extension study of protocol CT-EV-21, to evaluate the long-term immunogenicity of EV71vaccine. The first study visit will be approximately 3 or 4 years after the administration of first vaccination of EV71 vaccine or placebo in CT-EV-21 study; 4 years after the first vaccination for subjects 2 to < 6 years of age (2b), and 3 years after first dose for subjects 2 months to < 2 years of age (2c and 2d). Subjects of 2b will remain in the study for approximately 12 months and will have 2 clinic visits; subjects of 2c and 2d will remain in the study for approximately 24 months and will have 3 clinic visits. Immunogenicity response against EV71 virus antigen at each visit will be assessed.

Official Title
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Long-Term Immunogenicity Study of Inactivated EV71 Vaccine Produced in Vero Cells With Adjuvant AlPO4 in Children: Extension Study of Protocol CT-EV-21

Conditions
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Enterovirus 71 Human

Intervention / Treatment
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* Biological: EV71 vaccine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects who have completed participation in study CT-EV-21 part 2b, 2c, and 2d, and have received protocol specified doses of EV71 vaccine or Placebo (total of 2 doses in part 2b, and 3 doses for part 2c and 2d). The subjects' guardians are able to understand and sign the informed consent form. Exclusion Criteria: Subjects and/or guardians who refuse to comply with the study procedures

Ages Eligible for Study
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Minimum Age: 2 Years
Maximum Age: 9 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| EV71 Vaccine with Adjuvant AlPO4<br>EV71 Vaccine Produced in Vero Cells with Adjuvant AlPO4 | Biological: EV71 vaccine<br>* EV71 vaccine with Adjuvant AlPO4 and the placebo (Adjuvant AlPO4 only) were randomly administrated to subject in CT-EV-21 study<br>|
| Adjuvant AlPO4<br>Placebo (Adjuvant AlPO4 only) | Biological: EV71 vaccine<br>* EV71 vaccine with Adjuvant AlPO4 and the placebo (Adjuvant AlPO4 only) were randomly administrated to subject in CT-EV-21 study<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum neutralizing antibody titer | Geometric mean titer (GMT) of EV71 neutralizing antibody titers at 4 and 5 years after first dose of EV71 vaccination for subjects of 2b; and 3 to 5 years after first dose of EV71 vaccination for subjects of 2c and 2d. | Up to 5 years after first dose of EV71 vaccination | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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EV71 Vaccine