Risk-oriented approach in analyzing epidemiologic situation with incidence with tick-borne encephalitis on endemic territories

Sverdlovsk region is a zone with a strenuous natural-anthropogenic focus of virus tick-borne encephalitis (TBE). Incidence with the disease has decreased by 5 times over the last 20 years due to mass vaccination among population. Since 2015 incidence with TBE has remained steady at fewer than 3 cases per 100,000 people. However, over the last 10 years incidence with TBE has been decreasing at a significantly slower rate due to a considerable growth in number of immune people (from 68 % in 2007 to 84.99 % in 2018). Analysis revealed that probability of the disease after a person had been bitten by a tick was quite different on different territories in the region. Our research goal was to develop a procedure for ranking administrative territories as per risks of clinical TBE occurrence among people bitten by ticks. We took a number of people bitten by ticks per one TBE case as our risk parameter. Our analysis revealed that average regional risk reached its maximum values (1:40-1:50) in years prior to implementation of mass vaccination against TBE...