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

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.