Epidemiology of tick-borne encephalitis (TBE) in Europe and its prevention by available vaccines

Tick-borne Encephalitis (TBE), which is caused by a Flavivirus, is the most common tick-transmitted disease in Central and Eastern Europe and Russia. Today, TBE is endemic in 27 European countries, and has become an international public health problem. The epidemiology of TBE is changing owing to various factors, such as improvements in diagnosis and case reporting, increased recreational activities in areas populated by ticks, and changes in climatic conditions affecting tick habitats. Vaccination remains the most effective protective measure against TBE for people living in risk zones, occupationally exposed subjects and travelers to endemic areas. The vaccines currently in use are FSME-Immun(®), Encepur(®), EnceVir(®) and TBE vaccine Moscow(®). The numerous studies performed on the efficacy and safety of these vaccines have shown a high level of immunogenicity and an excellent safety profile. Several studies have also shown a high level of cross-protection among strains belonging to different subtypes.   In the present paper we attempted to describe the continuously changing epidemiology of TBE in European States and to overview clinical development of available vaccines paying particular attention on cross-protection elicited by the vaccines.