FSME-Immun® is registered for application into the muscle. This study investigates if application under the skin leads to a comparable immune response.

Tick-borne encephalitis (TBE) vaccine (FSME-Immun®) is registered for intra-muscular application. Due to medical reasons (e.g. anticoagulant therapy, adipositas) intra-muscular application is not always possible. The aim of this clinical trial is to investigate whether a comparably good immunogenicity can be achieved via the subcutaneous vaccination route. Thus humoral and cellular immune responses after intramuscular and subcutaneous TBE vaccination in healthy volunteers will be compared.

Inclusion Criteria:

• completed primary TBE immunization + at least one booster immunization
• adults of both sexes between 18 and 60 years of age
• willingness to sign written informed consent form

Exclusion Criteria:

• age < 18 and > 60 years
• prior TBE infection
• pregnancy and breast feeding
• acute infection on day of inclusion (day 0), (body temperature > 37,9°C)
• concomitant medications: systemic cortisone therapy, chemotherapy, immunosuppressive therapy 4 weeks prior to or during study
• administration of other vaccines 4 weeks before/after day 0
• planned surgery within 2 weeks before/after TBE booster vaccination
• specific immunotherapy (Hypo-/Desensibilisation) 14 days before/after vaccination
• any contraindication to administration of FSME-Immun® vaccine according to manufacturer's instructions
• history of malignant disease within the last 5 years
• autoimmune diseases
• drug addictions
• plasma donors
• receipt of blood transfusions or immuno globulins within 3 month before study entry