Study of ChimeriVax™-Japanese Encephalitis Vaccine in Toddlers in Thailand and the Philippines

Inclusion Criteria : * Aged 12 to 18 months on the day of inclusion. * In good general health, without significant medical history. * 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. * Subject and parent/legally acceptable representative able to attend all scheduled visits and comply with all trial procedures. * Completion of vaccinations according to the national immunization schedule. Exclusion Criteria : * Participation in another clinical trial investigating a vaccine, drug, medical device, or a medical procedure in the 4 weeks preceding the trial vaccination. * Planned participation in another clinical trial during the present trial period. * 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 systemic hypersensitivity to any of the vaccine components or history of a life-threatening reaction to a vaccine containing any of the same substances. * Chronic illness at a stage that could interfere with trial conduct or completion, in the opinion of the Investigator. * Receipt of blood or blood-derived products in the past 3 months, that might interfere with the assessment of the immune response. * Administration of any anti-viral within 2 months preceding V01. * History of central nervous system disorder or disease, including seizures. * Personal or family history of thymic pathology (thymoma), thymectomy, or myasthenia. * Receipt of any vaccine in the 4 weeks preceding the first trial vaccination. * Planned receipt of any vaccine in the 4 weeks following any trial vaccination. * Personal human immunodeficiency virus seropositivity in the blood sample taken at screening. * Receipt of any JE vaccine or hepatitis A vaccine. * Previous vaccination against flavivirus disease. * History of flavivirus infection (confirmed either clinically, serologically or microbiologically) * Thrombocytopenia, bleeding disorder or anticoagulants in the 3 weeks preceding inclusion contraindicating intramuscular vaccination. * Febrile illness (temperature ≥38°C) or moderate or severe acute illness/infection on the day of vaccination, according to Investigator judgment.