Immune Response in IXIARO Batch JEV09L37 Recipients Before and After Revaccination

Inclusion Criteria: * Subjects 18 years or older having received IXIARO batch JEV09L37 during primary immunization * In female subjects, either childbearing potential terminated by surgery or 1 year post-menopausal, or a negative urine pregnancy test during screening and the willingness not to become pregnant during the entire study period by practicing reliable methods of contraception * Written informed consent obtained from the subject prior to any study-related procedures Exclusion Criteria: * Vaccination against Yellow fever, Dengue Fever, West Nile Fever or TBE or vaccination with any JE vaccine since primary immunization with IXIARO JEC09L37 * Clinical manifestation of any flavivirus infection since primary immunization with IXIARO JEC09L37 * Acute febrile infections or exacerbation of chronic infection on the day of IXIARO vaccination * Pregnancy, lactation or unreliable contraception in female subjects with child-bearing potential and unreliable contraception in male subjects. * Use of any other investigational or non-registered drug within 30 days prior to the first vaccination with IXIARO Visit 1 and during the study period * Any condition which might interfere with study objectives or would limit the subject's ability to complete the study in the opinion of the investigator * Persons who are committed to an institution * At Day 0, upcoming scheduled travel to a JE endemic region