Effect of a Booster Dose of the Japanese Encephalitis Vaccine IC51

Main Inclusion Criteria: * Healthy adults who completed the primary immunization in study IC51 309 * Male and female healthy subjects aged at least 18 years with written informed consent and either no childbearing potential or negative pregnancy test Main Exclusion Criteria: • History of immunodeficiency or immunosuppressive therapy, known Human Immunodeficiency Virus (HIV), or drug addiction including alcohol dependence