The purpose of this study is to investigate the safety and immunogenicity of three different concentrations of a TBE vaccine in healthy children aged 1 to 6 years.

Inclusion Criteria:

Male and female children will be eligible for participation in this study if:

• they are 1 year (from the 1st birthday) to 6 years (to the last day before the 6th birthday) old;
• they are clinically healthy;
• their legal representative understands the nature of the study, agrees to its provisions and gives written informed consent;
• their legal representative agrees to keep a Volunteer Diary.

Exclusion Criteria:

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

• have a history of any previous TBE vaccination;
• have a history of TBE infection or show evidence of a latent TBE infection (as demonstrated by screening ELISA > 126 VIEU/ml and / or neutralization test > 1:10);
• have a history of allergic reactions, in particular to one of the components of the vaccine;
• have received antipyretics within 4 hours prior to the first TBE vaccination;
• suffer from a disease that cannot be effectively treated or stabilized;
• suffer from a disease (e.g. autoimmune disease) or are undergoing a form of treatment that can be expected to influence immunological functions;
• suffer from chronic, degenerative and / or inflammatory disease of the central nervous system;
• are known to be HIV positive (a special HIV test is not required for the purpose of the study);
• suffer from a febrile illness at study entry;
• have a history of vaccination against yellow fever and / or Japanese B-encephalitis;
• are participating simultaneously in another clinical trial.