Rapid Immunization Study of the Japanese Encephalitis Vaccine IC51

Inclusion Criteria: * At least 18 years of age * Written informed consent obtained prior to study entry Exclusion Criteria: * History of clinical manifestation of any flavivirus infection * History of vaccination against Japanese encephalitis (JE), Yellow fever and Dengue fever (an anti-JEV neutralizing antibody titer \>= 1:10 at baseline is acceptable for inclusion, these subjects will be part of the safety population, but will not be analyzed for immunogenicity in the per-protocol analysis) * Use of any other investigational or non-registered drug or vaccine in addition to the study vaccine during the study period or within 30 days preceding the first dose of study vaccine * Immunodeficiency including post-organ-transplantation or immunosuppressive therapy * A family history of congenital or hereditary immunodeficiency * History of autoimmune disease * Any acute infections within 4 weeks prior to enrollment * Infection with HIV, Hepatitis B or Hepatitis C * Pregnancy, lactation or unreliable contraception in female subjects