The objective of this study is to investigate the immunogenicity and safety of FSME-IMMUN 0.5 ml in two age strata (stratum A: 16 to 49 years, stratum B: > 50 years), with the first and second vaccinations being administered according to a rapid immunization schedule (12 ± 2 days apart). The third vaccination will be administered approximately 6 months after the first dose.

Inclusion Criteria:

Male and female subjects will be eligible for participation in this study if they:

• Understand the nature of the study, agree to its provisions and provide written informed consent (assent if the subjects is under 18 years of age);
• Provide the written informed consent of their parents / legal guardian (if the subject is under 18 years of age);
• Are aged >= 16 years (from the 16th birthday) at screening;
• Are clinically healthy, (i.e. the physician would have no reservations vaccinating with FSME-IMMUN 0.5 ml outside the scope of a clinical trial);
• Have a negative pregnancy test result at the first medical examination (if female and capable of bearing children);
• Agree to employ adequate birth control measures for the duration of the study (if female and capable of bearing children);
• Agree to keep a Subject Diary.

Exclusion Criteria:

Subjects will be excluded from participation in this study if they:

• Have a history of any previous tick-borne encephalitis (TBE) vaccination;
• Have a history of TBE infection;
• Have a history of infection with or vaccination against other flaviviruses (e.g. dengue fever, yellow fever, Japanese B-encephalitis);
• Have a history of allergic reactions, in particular to one of the components of the vaccine;
• Suffer from a disease (e.g. autoimmune disease) or are undergoing a form of treatment (e.g. systemic corticosteroids) that can be expected to influence immunological functions;
• Have a known or suspected problem with drug or alcohol abuse (> 4 liters wine / week or equivalent level of other alcoholic beverages);
• Have donated blood or plasma within 30 days of study entry;
• Have received a blood transfusion or immunoglobulins within 30 days of study entry;
• Are known to be HIV positive (an HIV test is not required specifically for the purpose of this study);
• Are simultaneously participating in another clinical trial including administration of an investigational product;
• Have participated in any other clinical study within six weeks prior to study entry;
• Are pregnant or breastfeeding (if female);
• Are a member of the team conducting this study or are in a dependent relationship with the study investigator. Dependent relationships include close relatives (i.e., children, partner/spouse, siblings, parents) as well as employees of the investigator.
• Have received any other vaccination within two weeks prior to study entry.