Investigation of the Seropersistence of TBE Antibodies and the Booster Response to FSME-IMMUN 0.5 ml in Adults Aged 18 - 67 Years

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

- received any TBE vaccination since their third vaccination with FSME-IMMUN 0.5ml;

- received a vaccination against yellow fever and / or Japanese B-encephalitis since
their third 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 third 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);

- have received a blood transfusion or immunoglobulins within one month to the first and
second blood draw;

- have participated in another Baxter vaccine study within the last six months (with the
exception of follow-up studies).

Subjects will not be eligible for booster vaccination if:

- they do not meet the inclusion/exclusion criteria;

- 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);

- they 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;

- they have donated blood or plasma within one month to the booster vaccination;

- female of childbearing potential are pregnant or breastfeeding before the booster
vaccination (positive pregnancy test result at the medical examination before the
booster vaccination);

- they have shown an allergic reaction to one of the components of the vaccine since
their third vaccination in Baxter Study 213;

- they 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.

Subjects who meet the inclusion/exclusion 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 received any vaccination within two 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 intended TBE
vaccination, the vaccination should be performed at a later time.