The Analysis of the Factors Determining Efficiency of Vaccination against Tick-Borne Encephalitis

Long-term persistence of immunity was assessed in 1756 healthy adults (4 - 74 years of age) with documented immunization against tick-borne encephalitis. Serologic studies indicate that the protective immunity is associated with age, number of vaccine doses and time since the last vaccine dose. 411 persons were vaccinated against tick-borne encephalitis over 10 years ago. Most of them (67,5%) had protective antibodies. In some cases, the immunity lasts up to 34 years after last vaccination.