Relevance.Тhe Ural Federal district (Ural Federal district) is a highly endemic tick-borne viral encephalitis (TBEV) territories in the Russian Federation. The epidemiological situation on the TBEV is studied in Sverdlovsk and Chelyabinsk regions and slightly shown in the Kurgan region. There is no information about the evolution TBEV, the structure of immunity population, vaccine prevention in the Kurgan region. The article presents the dynamics epidemiological situation on TBEV in the Kurgan region over a 30-year period.Materials and methods: Used expedition reports, viral encephalitis named after the Academy of medical Sciences of the USSR for 1983–2007, as well as materials of medical institutions of the Kurgan region 2007–2017. For population immunity used: hemagglutination test (HAI-test), neutralization test (NT). To identify specific antibodies – IgG, IgM, antigen of TBEV, sets of reagents of ELISA from «Vector-Best» were used. To immunotypicalli and genotypically Strains and isolates RNA of TBEV isolated in 1983–2007, used precipitation in agar (RDPA) and by RT-PCR technique in real time with genotypespecific probes.Results and discussions: Kurgan region is a highly TBEV endemic area. the morbidity rate – 18,3 per 100 thousand people 1983. Maximum elevation – 44.1 in 1996 to and decrease to 13.5 in 2000–2012. The immune part of the population according hemagglutination tests, on epidemiologically significant territories is 15–20%, (66% NT), in the regions with sporadic incidence is 8%, (21–50% NT), in non-endemic territories – 3%. At the present stage, the region marked the expansion of nosoareal TBEV due to the previously less significant Eastern regions. In Kurgan region vaccination coverage against TBE 39.3%. The clinical efficacy of vaccination was manifested in an increase in fever forms of TBE disease and a decrease in meningeal and focal forms of the disease. In the period 2004–2012 the number of vaccinated patients was 20.3% of the total number of patients.Сonclusions. Evolution of tick-borne encephalitis manifested the expansion of nosoareal TBEV, increase seasonal activity of ticks, the TBEV Siberian subtype is absolutely dominating.

Relevance.Modern inactivated culture vaccines against tick-borne encephalitis (TBE) with at least 70% of the population living in the  natural foci of the FE give a high epidemiological effect. Unresolved  issues are the simplification of the cumbersome vaccination scheme,  the optimal number of revaccinations, the protective titer of  antibodies against the Siberian subtype of the TBE virus dominant in Russia.Goalof this work is to study the state of postvaccinal immunity in the population of the highly endemic area of the Trans-Urals.Materials and methods. 1381 blood serum of the population vaccinated from 3 to 13 times with vaccines was studied: unconcentrated culture inactivated from strain No. 205 of the TBE  virus produced by «Virion», Tomsk, «EnceVir» produced by  «Microgen», Tomsk, produced by Chumakov Federal Scientific Center for Research and Development of Immuneand-Biological Products of  Russian.To identify specific antibodies – IgG, IgM, antigen of TBE  virus, sets of reagents of ELISA from «Vector-Best» were used.  Neutralizing activity of sera was determined by the index of  neutralization index with 4 strains of the Siberian subtype of TBE  virus.Results.The immune layer among the vaccinated population in 10 districts of the Kurgan region, which differ in epidemiological tension, ranges from 69.9% to 94.6%. The intensity of humoral immunity  varied according to IgG titers in ELISA from 1: 100 – 1: 200 to 1:  3200 (rarely 1: 6400). The duration and intensity of immunity  depends on the number of vaccinations and the number of missed  remote revaccinations. Preservation and intensity of immunity with  reliability P = 95%, higher in persons vaccinated 6–10 times  compared with the group of vaccinated 3 times. In persons who had 4–8 booster dose of vaccine, the immunity persisted for 15–19–36 years with an IgG titer of not more than 1: 100. The neutralizing  activity of the sera of vaccinated individuals with antibody titers from 1:100 to 1: 6400 was studied for the Siberian subtype of BCE. The  degree of protection of the vaccinated population against the doses  of the virus found in individual mites is determined. From the doses  of the virus, 57% of the vaccinated population are most often found  in mites, and from the dose of 105– 8%. Recommendations are  proposed on the tactics of revaccination of the population, depending on the level of immunity.