Clinical and Epidemiological Features of Actual Tick-Borne Infections under Conditions of Mass Vaccination against Tick-Borne Viral Encephalitis (by the Example of a Megapolis)

Relevance. The clinical aspects of tick­borne viral encephalitis (TBE) and Lyme borrelliosis (LB) as monoinfections are well known. At the same time, the issues of interaction of pathogens in tick­borne encephalitis – Lyme borrelliosis mixed infection (TBE – LB mixed infection), the effectiveness of specific prophylaxis, their effect on the incidence rate and clinical forms have not been sufficiently studied.Aims. The aim of this work was to study the clinical course of TBE and TBE ­ LB mixed infection in patients with specific prophylaxis of TBE, as well as in its absence.Materials & Methods. Medical history data from 454 patients patients with a confirmed diagnosis of TBE and TBE – LB mixed infection during 2010–2017 were analyzed.Results. The clinical course of the disease in TBE mono­- and mixed infection, as well as the connection of immunization with the clinical forms of the disease are reflected. The dynamics of the registration of clinical forms of TBE and TBE – LB mixed infection for 8 years was shown using regression models. Synchronization of the incidence of focal and meningeal forms in TBE and TBE – LB mixed infection with a statistically significant decrease in the frequency of their occurrence was noted. The incidence of febrile forms in TBE monoinfection, as well as in mixed infections, remained practically unchanged.Сonclusions. It was found that the incidence of severe focal and meningeal forms of the disease in patients with TBE – LB mixed infection was 1.5 times lower, and the proportion of patients with febrile form TBE was statistically significantly higher than in the group of patients with TBE monoinfection, which may indicate a more favorable during TBE ­ LB mixed infection, and overdiagnosis of febrile form TBE in TBE – LB mixed infection. The increase in the rate of vaccination against TBE of the population contributed to a decrease in the number of TBE и TBE – LB mixed infection cases due to severe clinical forms (focal and meningeal).