Southern Bohemia is one of the extensive natural foci of tick-borne encephalitis (TE) in the Czech Republic. Some professionals hold the view that people living in the focus of infection acquire naturally herd immunity and are the protected against the infection and thus it is not necessary to vaccinate them against TE. Several serious cases of the disease in temporal sequence in Římov in the district of České Budějovice led the authors to examine more closely the problem of TE in this locality. Available epidemiological data were analyzed. A group of subjectswith permanent residence in the community was assembled who were interested to participate in the trial. In these serological examinations were made to assess antibodies against TE. Analysis of the assembled data proved that during permanent residence in Římov 6.07% of the investigated group during their life in Římov developed the manifest form of TE, 9.64% developed the inapparent form and 15% subjects had antibodies after previous vaccination. The ratio of manifest and inapparent cases is 6.07:9.64, i.e.roughly 2:3. The total seroprevalence after the disease (manifest and inapparent) is 16%. Persons with a negative result of the examination were offered vaccination. The vaccination rate increased due to the authors’ intervention from 15% to 65% in the given community.

        Key words: epidemiological survey of tick-borne encephalitis – ratio of manifest and inapparent cases – postvaccination antibody response – vaccination rate against tick-borne encephalitis in Římov, southern Bohemia