Abstract. The comprehensive clinical-immunological characteristic of a tick-borne encephalitis vaccine En-cepur Adult (Germany), which was studied on a group of residents of Far East of Russia was discussed. Reactogenity in 32,4% of vaccinees was characterized by minor clinical manifestations and was due to the reaction to specific vaccine albumin. Expression of immune response (mean geometric titers) was evaluated in a neutralization test. A group with the reactogenity showed higher geometric mean antibody titers (1:182) compared with a group without the reactogenity (1:97).

All of vaccinees with various levels (high, middle, low) of specific immune response had an increased quantity of CD20+ and CD25+ lymphocytes. We showed a difference in immunologic reactivity of people with high and low levels of specific antibody response. As compared with a low level group the group with a high level of specific response showed significantly higher quantity of lymphocytes and their subpopulations (CD3+, CD4+, CD45RA+) as well as higher levels of IgM, IgG.

We conclude that vaccine Encepur Adult (Germany) possesses a high immunologic activity. It is recommended to use this vaccine as a safe and effective specific preventive remedy in TBE endemic areas.