Long-term Follow-up of Immunogenicity of a Single Dose of Japanese Encephalitis Chimeric Virus Vaccine (JE-CV) in Toddlers

Study Overview
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Brief Summary
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This is a long-term follow-up of the persistence of immune response in participants who previously received a single dose of JE-CV at age 12 to 18 months in Study JEC02 (NCT00735644) . No vaccination was administered during the present long-term follow-up study. Primary Objective: To describe the yearly persistence of humoral immune response to Japanese encephalitis after a single dose of JE-CV

Detailed Description
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Persistence of immune response will be determined in participants who previously received a single dose of JE-CV at age 12 to 18 months in Study JEC02 (NCT00735644). No vaccination will be given in this study.

Official Title
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Long-term Follow-up of Immunogenicity of a Single Dose of JE-CV in Toddlers in Thailand and the Philippines

Conditions
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Encephalitis, Japanese Encephalitis

Intervention / Treatment
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* Other: Blood sample
* Biological: JE-CV administered in Study JEC02


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria : Provision of Informed Consent Form signed by at least one parent or other legally acceptable representative, and by at least one independent witness if required by local regulations. Participant who was vaccinated with JE-CV in JEC02 trial and had a pre-vaccination blood sample at baseline in JEC02 trial. Participant and parent/legally acceptable representative able to attend all scheduled visits and comply with all trial procedures. Exclusion Criteria : Receipt of any JE vaccine other than JE-CV during JEC02 trial and during the period up to inclusion in JEC05 trial. Planned participation in another clinical trial up to the first year of the follow-up in the present trial.

Ages Eligible for Study
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Minimum Age: 2 Years
Maximum Age: 3 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
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Study group<br>Participants received a single dose of JE-CV administered in Study JEC02. In Study JEC05 there were yearly visits with blood samples taken for immunogenicity assessment. | Other: Blood sample<br>* Blood sample for immunogenicity assessment<br>Biological: JE-CV administered in Study JEC02<br>* Participants received a single dose of JE-CV at 12 to 18 months of age in Study JEC02. No vaccination was administered in Study JEC05<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants With Japanese Encephalitis Seroprotection Following a Single Dose of JE-CV | Seroprotection was defined as the proportion of participants with Japanese encephalitis virus neutralizing antibody titers ≥10 1/dil as measured by a JE 50% plaque reduction neutralization test (PRNT50). | Day 0 (pre-vaccination) from study JEC02, Day 28 post-vaccination from study JEC02, and at Years 1, 2, 3, 4, and 5 post-vaccination | 
| Summary of Geometric Mean Titers of Japanese Encephalitis Virus Antibodies Following a Single Dose of a JE-CV | Geometric mean titers of Japanese encephalitis virus antibodies were assessed using the PRNT50 test. | Day 0 (pre-vaccination) from JEC02, Day 28 post-vaccination from JEC02, and at Years 1, 2, 3, 4, and 5 post-vaccination | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Encephalitis, Japanese Encephalitis, Japanese Encephalitis Chimeric Virus Vaccine, Toddlers