Infectious pathology continues to occupy one of the leading places in the structure of causes of death worldwide and in developing countries prevails over somatic. The most cost-effective way to prevent infectious diseases is vaccination. However, the use of vaccines cannot be implemented to combat all known infectious diseases, given their massive nature and often occurring polyetiology. In this regard, non-specific prevention is of particular relevance. In order to systematize and generalize the data of the scientific literature on methods and means of non-specific prevention, as well as to assess their effectiveness, a search for literary sources using electronic bibliographic resources was carried out https://pubmed.ncbi.nlm.nih.gov/ and https://elibrary.ru/ according to the keywords «non-specific prevention», «prevention of infections». The analysis of scientific works made it possible to evaluate non-specific prevention from the standpoint of classical epidemiology and the population approach to the organization of epidemiological studies and planning of preventive measures. The measures aimed at the source of infection, the mechanism of transmission and the susceptible organism in relation to different groups of infection are considered. Priority preventive and anti-epidemic measures were identified in relation to infections with aerosol, fecal-oral, contact and transmissible transmission mechanisms, and their effectiveness was evaluated. Special attention is paid to measures for the prevention of zoonotic and natural focal infections, as well as measures for the sanitary protection of the territory of the state from the import and spread of infectious diseases. The applicability of non-specific prevention of infectious morbidity in the conditions of the emergence of new biological threats is considered on the example of a new coronavirus infection COVID-19. It is established that the scientifically based tactics and methodology of non-specific prevention of infectious diseases are the property of domestic and world epidemiology, and its effectiveness has been tested by time and does not lose relevance today. The risk of new threats indicates that the improvement of this approach is a promising direction for the prevention of infectious diseases.

Hepatitis B is an infectious disease that leads to severe health problems, with the risk of chronicity and death. The World Health Organization (WHO) has shown that about 4.5 million premature deaths from the infection could be prevented by 2030 in low- and middle-income countries through vaccination, diagnostic tests, drugs, and education campaigns. The main goal of the WHO global hepatitis strategy is to reduce new infections by 90 % and deaths by 65 % between 2016 and

2030. The successes of hepatitis B vaccine prophylaxis are the basis for setting the ambitious goal of eliminating the disease in the future. However, to date, many questions about the organization and planning of regional vaccination programs remain unresolved and provoke discussions among specialists around the world, including in Russia. In order to systematize and summarize the scientific literature on prevention, as well as to evaluate its effectiveness, we performed a literature search using the electronic bibliographic resources https://pubmed.ncbi.nlm.nih.gov/ and https://elibrary.ru/ using the key words «hepatitis B» and «vaccine prophylaxis». Analysis of scientific papers allowed us to characterize some manifestations of hepatitis B epidemic process and reveal its modern features in the territory of Russia, including risk groups. Aspects of genetic heterogeneity of HBsAg pathogen circulating in Russian territory as well as in adjoining states are given in details. The organization of vaccine prophylaxis is considered; the used immunobiological preparations are characterized. The results of the work define the role of serological studies in the system of epidemic surveillance for hepatitis B, as well as their significance for formation of adequate tactics of vaccination of the population, including in risk groups.

The most important aspect of the problem of the quality of medical care is the epidemiological safety of the therapeutic and diagnostic process. The intensive development of high-tech, invasive methods of diagnosis and treatment, combined with the widespread spread of multidrug-resistant microorganisms, determine the need for continuous improvement of the system of supervision and control of infections associated with medical care (ISMP). The aim of the study was to identify cases of ventilator-associated lower respiratory tract infections in intensive care units (ICU) when infected with ESСAPE group bacteria; to study their prevalence, etiological structure and epidemiological significance in intensive care patients with COVID-19 undergoing invasive artificial ventilation (ventilator). The results of the study showed that in COVID-19 patients who received respiratory support in the ventilator mode, representatives of the ESСAPE group of bacteria (with genetic determinants of multiantibiotic resistance) were found more than 2 times more often than in surgical patients, which indicates the important epidemiological significance of aerobic gram-negative bacteria and non-fermenting gram-negative bacteria of the ESСAPE spectrum in patients COVID-19 in the formation of colonization and ventilator-associated infection of the respiratory tract. At the same time, both in COVID-19 patients and in patients with a surgical ICU, gram-negative bacteria of the genus Klebsiella spp., producing beta-lactamase, as well as non-fermenting gram-negative microorganisms Acinetobacter spp, were prioritized in the etiological structure and P. aegidiposa, characterized by pronounced acquired resistance to antibiotics of the carbapenem group and are the prerogative of intensive care units. To ensure the epidemiological safety of medical care during ventilation, it is necessary to implement a strategy of empirical and targeted antibiotic therapy; monitoring of antibiotic resistance; conduct continuous epidemiological surveillance in the ICU with full collection of information on etiological agents, cases of respiratory tract infection and tighten epidemiological control over the preparation and conduct of ventilation.