Study of Japanese Encephalitis Chimeric Virus Vaccine Given With Measles-Mumps-Rubella Vaccine in Taiwanese Toddlers

This study is designed to compare the immunogenicity of Japanese encephalitis chimeric virus vaccine (JE-CV) and measles-mumps-rubella (MMR)vaccine when given together or when given at separate visits 6 weeks apart in toddlers aged 12 to 18 months.

Primary objective:

* To demonstrate the non-inferiority of the antibody responses in terms of seroconversion of the concomitant administration of JE-CV and MMR compared to the antibody responses after the single administration of JE-CV and MMR vaccine.

Secondary objectives:

* To describe the immune response to JE CV and MMR before and after one dose of JE CV and MMR vaccine, respectively.
* To describe the safety of a single dose of JE-CV and MMR vaccine (given separately at a 6-week interval and the safety of the concomitant administration of JE-CV and MMR vaccine in all subjects up to 6 months after last vaccination.

All participants will receive Japanese encephalitis chimeric virus vaccine and measles-mumps-rubella vaccine and will be monitored for safety throughout the study.

Eligibility Criteria:
Inclusion Criteria

* Aged 12 to 18 months on the day of inclusion .
* Born at full term of pregnancy (≥ 37 weeks) and with a birth weight ≥ 2.5 kg.
* Subject in good health based on medical history and physical examination.
* Provision of informed consent form signed by at least one parent or other legally acceptable representative, and by an independent witness if the parents or legally acceptable representative cannot read.
* Subject and parent/legally acceptable representative or delegate able to attend all scheduled visits and comply with all trial procedures.

Exclusion Criteria

* Participation in another clinical trial investigating a vaccine, drug, medical device, or a medical procedure in the 4 weeks preceding the first trial vaccination.
* Planned participation in another clinical trial during the present trial period.
* Receipt of any vaccine in the 4 weeks preceding the first trial vaccination except for pandemic influenza vaccination, which may be received at least two weeks before the study vaccines.
* Planned receipt of any vaccine up to the 6 weeks following the last trial vaccination except for pandemic influenza vaccine. In the event of a local or national immunization program with a pandemic influenza vaccine, participants who receive a pandemic influenza vaccine at any time during the trial will not be withdrawn from the trial.
* Previous vaccination against measles, measles-mumps-rubella (MMR), or flavivirus disease, including Japanese encephalitis (JE).
* Receipt of blood in the past 6 months that might interfere with the assessment of the immune response
* Receipt of intravenous injection of plasma, platelet product, or high dose of intravenous immunoglobulin in the past 11 months
* Receipt of intramuscular treatment of immunoglobulin or Hepatitis B immunoglobulin in the past 3 months
* Known or suspected congenital or acquired immunodeficiency, immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 6 months, or long-term systemic corticosteroids therapy.
* Known history of human immunodeficiency virus, hepatitis B surface antigen, or hepatitis C seropositivity.
* History of measles, mumps, rubella, or flavivirus infection confirmed either clinically, serologically, or microbiologically.
* Known systemic hypersensitivity to any of the vaccine components or history of a life-threatening reaction to a vaccine containing any of the same substances .
* Known systemic hypersensitivity to gelatin, eggs, or anaphylactic/anaphylactoid reaction to neomycin.
* Known history of thrombocytopenia.
* Administration of any anti-viral within 2 months preceding first vaccination and up to the 6 weeks following the last trial vaccination.
* History of central nervous system disorder or disease, including seizures and febrile seizures.
* Chronic illness at a stage that could interfere with trial conduct or completion, in the opinion of the Investigator.