Response to tick-borne encephalitis (TBE) booster vaccination after prolonged time intervals to primary immunization with the rapid schedule.

Tick-borne encephalitis can be prevented by active immunization, for which different schedules and booster recommendations exist. However, recommended booster intervals are often exceeded. In the present study, 178 adults aged 18-81 years received the first booster dose 2-11 years after primary immunization (instead of 12-18 months as recommended) according to the rapid schedule (vaccination on days 0, 7, and 21). The booster dose was well tolerated. All subjects showed a typical anamnestic response with an 11-fold increase in the geometric mean titre as measured both by neutralization test and ELISA.