Tick-borne encephalitis (TBE) is a disease of the central nervous system caused by a tick-borne viral infection. TBE can lead to severe neurological syndromes, which can result in death. Many species of wild and domestic animals act as hosts of ticks; transmission to humans occurs often in woodland areas, especially during the summer, which is the time of greatest human outdoor activity. TBE is particularly prevalent in Central and Eastern Europe.
Although personal protective measures to avoid tick bites (such as insect repellents, avoidance of tick-infested areas, and use of protective clothing) are recommended, there is no effective treatment for TBE, and vaccination is the only preventive measure currently available.
This review evaluates the effectiveness and adverse events induced by current vaccines for preventing TBE. The authors identified 11 trials involving 8184 participants, which assessed different versions of three types of tick-borne encephalitis vaccines. No trials reported on cases of clinical TBE, but all tested vaccines were highly immunogenic. Adverse effects were commonly reported, none were serious or life threatening.
The authors recommend further trials or well-conducted observational studies with clinical outcomes (ie TBE cases) to better estimate vaccine effectiveness and the duration of vaccine protection, as well as long-term adverse events.