Study of a Booster Dose of IMOJEV® One Year After Primary Immunization in Healthy Children in South Korea

Study Overview
=================
Brief Summary
-----------------
The aim of this study was to document the immunogenicity and safety of a booster dose of IMOJEV administered at least 12 months after the primary dose. Primary objective: To describe the immune response to Japanese Encephalitis (JE) before and 28 days after a booster dose of IMOJEV administered at least 12 months after primary vaccination with IMOJEV. Exploratory objectives: To describe the safety profile of a booster dose of IMOJEV® .

Detailed Description
-----------------
Participants who previously participated in Study JEC12 (NCT01396512) and were primed with IMOJEV received a booster dose of IMOJEV at least 12 months after the primary dose. Participants were assessed for immune response before and on Day 28 after the booster dose and were monitored for safety through Day 28 post-vaccination for non-serious adverse events (AEs) and up to 6 months post-vaccination for serious AEs The duration of each participant's participation in the study was approximately 6 months.

Official Title
-----------------
Immunogenicity and Safety Exploration of a Booster Dose of a Live Attenuated Japanese Encephalitis Chimeric Virus Vaccine (IMOJEV®) Given One Year After Primary Immunization in Healthy Children in South Korea

Conditions
-----------------
Japanese Encephalitis

Intervention / Treatment
-----------------
* Biological: IMOJEV


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Must have participated in study JEC12 and received 1 dose of IMOJEV at least 12 months before booster vaccination Age 2 to 4 years on the day of inclusion In good general health at the time of inclusion Informed Concent Form signed and dated by parent(s) or another legally acceptable representative(s) Subject and parent(s)/legally acceptable representative(s) able to attend all scheduled visits and comply with all study procedures. Exclusion Criteria: Participation at the time of study enrollment (or in the 4 weeks preceding the trial vaccination) or planned participation during the present trial period in another clinical study investigating a vaccine, drug, medical device, or a medical procedure in the 4 weeks preceding the study vaccination Known or suspected congenital or acquired immunodeficiency, or receipt of immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 6 months, or long-term systemic corticosteroids therapy Known systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccine used in the trial or to a vaccine containing any of the same substances Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with trial conduct or completion Receipt of immune globulins, blood or blood-derived products in the past 3 months, that might interfere with the assessment of the immune response Previous vaccination against flavivirus disease, including JE, with another vaccine, except with IMOJEV® while participating in JEC12 Administration of any anti-viral within 2 months preceding Visit 1 and up to the 4 weeks following the study vaccination Receipt of any vaccine in the 4 weeks preceding the trial vaccination or planned receipt of any vaccine in the 4 weeks following the trial vaccination, except for inactivated influenza vaccination, which may be received at least 2 weeks before the study vaccine History of central nervous system disorder or disease, including seizures Planned receipt of any JE vaccine during the course of the study History of flavivirus infection (confirmed either clinically, serologically or virologically) Administration of systemic corticosteroids for more than 2 consecutive weeks within the 4 weeks preceding vaccination Thrombocytopenia, contraindicating vaccination Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating vaccination Febrile illness (temperature ≥38.0°C) or moderate or severe acute illness/infection 3 days before vaccination as well as the day of vaccination, according to Investigator judgment. A prospective subject should not be included in the study until the condition has resolved or the febrile event has subsided In an emergency setting or hospitalized involuntarily Identified as a natural or adopted child of the Investigator or employee with direct involvement in the proposed study.

Ages Eligible for Study
-----------------
Minimum Age: 2 Years
Maximum Age: 4 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: IMOJEV Group<br>Participants who received a single dose of IMOJEV in study JEC12 (NCT01396512) will receive a booster dose in this study. | Biological: IMOJEV<br>* 0.5 mL, Subcutaneous<br>* Other names: Japanese Encephalitis Chimeric Virus Vaccine;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants With JE Seroprotection Before and Following a Booster Dose of IMOJEV Given One Year After Primary Immunization | JE virus neutralizing antibodies were measured using a 50% plaque reduction neutralization test (PRNT50). Seroprotection status for antibody levels against JE virus before and after IMOJEV vaccination was defined as antibody titers ≥ 10 (1/dilution). | Day 0 (pre-booster) and Day 28 post-booster injection | 
| Percentage of Participants With JE Seroconversion Following a Booster Dose of IMOJEV Given One Year After Primary Immunization | JE virus neutralizing antibodies were measured using PRNT50. Seroconversion was defined as a pre-vaccination titer <10 (1/dilution) and post-vaccination titer ≥10 (1/dilution, or pre-vaccination titer ≥10 (1/dilution) and a ≥4-fold increase of titers from pre- to post-vaccination. | Day 28 post-booster injection | 
| Summary of Geometric Mean Titers of JE Virus Antibodies Following a Booster Dose of IMOJEV Given One Year After Primary Immunization | JE virus neutralizing antibodies were measured using PRNT50 test. | Day 0 (pre-booster) and Day 28 post-booster injection | 
| Summary of Geometric Mean Titer Ratios of JE Virus Antibodies Following a Booster Dose of IMOJEV Given One Year After Primary Immunization | JE virus neutralizing antibodies were measured using PRNT50. | Day 0 (pre-booster) and Day 28 post-booster injection | 
| Percentage of Participants With JE Seroprotection Before and After a Booster Dose of IMOJEV Given At Different Intervals After Primary Immunization | JE virus neutralizing antibodies were measured using PRNT50. Seroprotection was defined as neutralizing antibody titer ≥ 10 (1/dilution). | Day 0 (pre-booster) and Day 28 post-booster injection | 
| Percentage of Participants With JE Seroconversion Following a Booster Dose of IMOJEV Given At Different Intervals After Primary Immunization | JE virus neutralizing antibodies were measured using PRNT50. Seroconversion was defined as a pre-vaccination titer <10 (1/dilution) and post-vaccination titer ≥10 (1/dilution, or pre-vaccination titer ≥10 (1/dilution) and a ≥4 fold increase from pre- to post-vaccination. | Day 28 post-booster injection | 
| Summary of Geometric Mean Titers of JE Virus Antibodies Following a Booster Dose of IMOJEV At Different Intervals After Primary Immunization | JE virus neutralizing antibodies were measured using PRNT50. | Day 0 (pre-booster) and Day 28 post-booster injection | 
| Summary of Geometric Mean Titer Ratios of JE Virus Antibodies Following a Booster Dose of IMOJEV Given At Different Intervals After Primary Immunization | JE virus neutralizing antibodies were measured using PRNT50. | Day 0 (pre-booster) and Day 28 post-booster injection | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Japanese encephalitis, Japanese encephalitis chimeric virus vaccine, IMOJEV®