Inclusion Criteria:

• Male and female children who participated in Study 146A if:
• they and/or their parents/legal guardians understand the nature of the study and agree to its provisions
• written informed consent is available from the child (according to age and capacity of understanding) and the parents/legal guardians
• they received the complete 3-immunization primary vaccination series with either 0.5 ml or 0.25 ml TicoVac in Study 146A
• they received FSME-IMMUN 0.25 ml Junior for their first booster vaccination approximately 3 to 4 years after their third vaccination in Study IMAG-146A

Exclusion Criteria:

• Subjects who received any further TBE vaccination since their first TBE booster vaccination
• Subjects with a history of infection with, or vaccination against, other flaviviruses (e.g. dengue fever, yellow fever and/or japanese B encephalitis virus) since their third vaccination in Study 146A
• Subjects who have suffered from a disease (e.g. autoimmune disease) or have undergone a form of treatment (e.g. systemic corticosteroids) that can be expected to influence immunological functions within 30 days before and after their first TBE booster vaccination
• Subjects who have been known to be HIV positive (a special HIV test is not required for the purpose of the study) since their third vaccination in Study 146A
• Subjects who have received a blood transfusion or immunoglobulins within 30 days of study entry