TBE Antibody Persistence and Booster Vaccination Study in Adults (Follow-up to Study 223)

The purpose of this study is to assess:

* TBE antibody persistence 24, 34, 46 and 58 months (as applicable) after the first booster TBE vaccination with FSME-IMMUN 0.5ml given in Study 223, by means of ELISA (IMMUNOZYM FSME IgG) and Neutralization test (NT),
* TBE antibody response to a second booster vaccination with FSME-IMMUN 0.5ml in the present study, by means of ELISA and NT,
* Safety of FSME-IMMUN 0.5ml after the second booster vaccination.


Eligibility Criteria:
Inclusion Criteria:

* Subjects who participated in Study 223 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
* they received the first booster vaccination with FSME-IMMUN 0.5ml during the course of study 223
* blood was drawn after their first booster vaccination in Study 223.

Exclusion Criteria:

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

* received any TBE vaccination since their first booster vaccination with FSME-IMMUN 0.5ml
* have a history of infection with or vaccination against other flaviviruses (e.g. dengue fever, yellow fever, Japanese B-encephalitis) since their first booster vaccination with FSME-IMMUN 0.5ml
* are known to be HIV positive (a special HIV test is not required for the purpose of the study) since their first booster vaccination with FSME-IMMUN 0.5ml
* have a known or suspected problem with drug or alcohol abuse (\> 4 liters wine / week or equivalent level of other alcoholic beverages).

Subjects will not be eligible for booster vaccination if they:

* are not clinically healthy, (i. e. the physician would have reservations vaccinating with FSME-IMMUN 0.5ml outside the scope of a clinical trial)
* 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
* are females of childbearing potential and are pregnant or breastfeeding before the booster vaccination (positive pregnancy test result at the medical examination before the booster vaccination)
* have shown an allergic reaction to one of the components of the vaccine since their first booster vaccination in Study 223
* are simultaneously participating in another clinical trial including administration of an investigational product within six weeks prior to the booster vaccination until the end of the study
* do not agree to keep a Subject Diary.
* Subjects who meet the eligibility criteria, but have a febrile illness (body temperature \>= 38.0°C, measured orally) at the scheduled time of vaccination, will not be vaccinated until their body temperature returns to normal.
* Subjects who have been administered any vaccination within 2 weeks prior to the booster vaccination will not be vaccinated until an interval of two weeks has passed.
* If subjects have received antipyretics within 4 hours prior to the scheduled time of vaccination, the vaccination should be performed at a later time.
* If a subject had a tick-bite within 4 weeks of the scheduled booster vaccination, the vaccination shall be delayed such that an interval of 4 weeks has passed since the tick-bite in order to avoid any interference with diagnostic assays in the event of a TBE infection.
* If a subject has donated blood or plasma or has received a blood transfusion or immunoglobulins within 4 weeks of the scheduled booster vaccination, the vaccination shall be delayed until an interval of 4 weeks has passed.