Inclusion Criteria:

• Male and female subjects who:
• received 2 vaccinations with FSME-IMMUN 0.5 ml during Study 225
• understand the nature of the study, agree to its provisions and provide written informed consent
• are clinically healthy (i.e. the physician would have no reservation vaccinating with FSME-IMMUN 0.5 ml outside the scope of the 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 who:

• have already been administered a third TBE vaccination elsewhere since receiving two vaccinations in Study 225
• have a history of infection with, or vaccination against, other flaviviruses since participation in Study 225 (e.g. yellow fever, dengue fever, japanese B encephalitis)
• have had an allergic reaction to one of the components of the vaccine since participation in Study 225
• suffer from a disease (e.g. autoimmune disease, immunodeficiency) 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 doses 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 this study)
• are simultaneously participating in another clinical trial including administration of an investigational product
• have participated in any other clinical study within 6 weeks prior to study start
• have participated in another Baxter vaccine study in the past 6 months (with the exception of follow-up studies)
• For female subjects: pregnancy or lactation