The intensive development of medical technologies is accompanied by equally rapid changes in the epidemic process of healthcare-associated infections (HAIs). According to experts, in order to increase the sensitivity of the surveillance system, official registration should be supplemented by multicenter targeted studies.
Aim. To determine the prevalence and incidence of HAIs in the intensive care units (ICUs) of the Russian Federation, the dominant pathogens and their antibiotic resistance.
Materials and Methods. A one-day epidemiological interregional multicenter cross-section survey of HAIs in the ICUs of the Russian Federation (EMMI) was carried out. 54 ICUs from 50 medical organizations in 27 subjects of the Russian Federation (25 specialized and 25 general hospitals) of all federal districts voluntarily participated in the study.
Results. The prevalence of HAI in the intensive care unit (Ward-Specific Point Prevalence) was 19.88% [13.94–25.5]. The Incidence Density of HAI was 19.72 [15.5–25.1] cases and 28.52 [23.3–34.8] episodes per 1000 patient-days (in adults – 22.52 [17.1–29.6] cases and 32.88 [26.2–41.2] episodes of HAI per 1000 patient-days; in children – 13.54 [8.3–23.1] cases and 19.51 [12.6–29.8] episodes per 1000 patient-days; in children under 1 year – 11.44 [5.9–21.2] cases and 17.16 [10.2–28.4] episodes per 1000 patient-days). The Device-specific Incidence Density of catheter-associated bloodstream infections (CLABSI) was 7.12 [6.39–7.81] per 1000 catheterization days, catheter-associated urinary tract infections (CAUTI) – 10.99 [9.99-11.99] per 1000 catheterization days, lower respiratory tract infections – 14.56 [11.0–19.3] per 1000 patient-days and 27.33 [25.77–28.89] per 1000 days of mechanical ventilation (VAP). Three microorganisms were in the lead: Klebsiella pneumoniae (33/35.48%), Acinetobacter baumannii (16/17.20%) and Pseudomonas aeruginosa (12/12.90%). In the group of ventilator-associated pneumonia, Klebsiella pneumoniae caused 47.82% of all cases. Multidrug resistance was demonstrated by 75% of Klebsiella pneumoniae strains.
Conclusion. A multicenter One-day point-prevalence survey allowed to clarify the prevalence and incidence density of HAIs in the ICU, and also revealed the dominance of multidrug-resistant Klebsiella pneumoniae in all regions as a causative agent of various forms of HAIs in the ICU. A high level of VAP was revealed, which requires additional research in order to adjust the preventive measures taken into account the characteristics of Klebsiella pneumoniae.

Relevance. In the establishment of a unified epidemiological surveillance system for measles, rubella, and mumps, virological monitoring of the circulation of these pathogens is essential. While standardized methods for monitoring the circulation of measles and rubella viruses and interpreting the obtained data are recommended by the WHO and applied globally, no such practice exists for the mumps virus. This study focuses on examining the genetic diversity of the mumps virus in Russia using molecular epidemiological methods previously validated by the authors.
Aim. To investigate the genetic diversity of the mumps virus in Russia in 2022–2023.
Materials and methods. Biological material samples from 25 patients diagnosed with "Mumps" were obtained from regions with high and low mumps incidence in 2022–2023. Viral RNA extraction, RT-PCR, Sanger sequencing, and bioinformatic data analysis were conducted. The identified nucleotide sequences were deposited in the GenBank database.
Results. The study found that mumps viruses of genotype G circulated in Russia in 2022–2023. Transmission of two genetic groups, G1 and G2, was identified. Genogroup G1 belongs to the genetic lineage MuVi/Sheffield.GBR/1.05, and genogroup G2 to MuVi/Gloucester.GBR/32.96. The circulation area for each genetic group was determined.
Conclusions. Despite both genogroups being predominantly represented by viruses isolated in Russia, the lack of significant correlation between distance matrices does not allow for a conclusion about the endemic transmission of genogroups G1 and G2 in the country based on the available molecular data. Within the framework of the National Program "Elimination of Measles and Rubella, Achieving Sustainable Sporadic Incidence of Mumps," the study of circulating mumps virus genotypes is relevant and will be continued.

Relevance. In the modern period, there are more and more publications showing that the COVID-19 pandemic has significantly affected the epidemiological situation with regard to a wide variety of infections, and having a different transmission mechanism. At the same time, ambiguous opinions are expressed about the causes of this phenomenon. Therefore, it is important to understand to what extent the reduction in morbidity is associated with the introduction of quarantine measures, or whether the mechanisms of competition between various infectious agents are important at the population level.
Aims. To assess the dynamics of the epidemic process (EP) of COVID-19, influenza and acute respiratory viral infections in the population of different subjects of the Far Eastern Federal District in the period from 2019 to 2023. substantiating the hypothesis about the causes (factors) that influenced it. Materials and methods. The material for the study was data on morbidity taken from state reports "On the state of sanitary and epidemiological welfare of the population" for the subjects of the Far Eastern Federal District and in the Russian Federation, and Internet sources for 2019 – 2023. The main method was a retrospective epidemiological analysis of morbidity, using an integration approach (Pozdeeva E.S., Yakovlev A.A., 2012), which allows us to identify possible interactions between microorganisms. For ease of perception and the ability to present several curves in one figure at once, in this work, the incidence is calculated in terms of visibility, on the basis of which graphs are constructed reflecting the dynamics of the incidence of the infections in question.
Results. The assessment of the dynamics of the incidence of SARS, influenza and COVID-19 in the Far Eastern Federal District did not reveal cardinal features in the dynamics of these infections in different administrative territories, which indicates the predominant influence of globally acting factors on the epidemic process. This probability reflects the theoretical views of Schmalhausen I.I. (1968), Yakovleva A.A. et al. (2018), that the biogeocenosis (global factor) acts as the controlling device in relation to all its constituent populations of species. Its self-adjustment forms the basis for the adaptability of species to their habitat and their mutual adaptation to each other. Therefore, changes in one parasitic system can also affect the parasitic systems of other infections, which are interconnected by integration and competitive relationships. This is reflected in the various manifestations of the epidemic process in different groups of infections.
Conclusions. Trends in the dynamics of the incidence of COVID-19, influenza and other acute respiratory infections in most administrative territories of the Far Eastern Federal District in the period 2019–2023, as well as in the region of the Far Eastern Federal District and the Russian Federation as a whole, do not have cardinal features. this indicates the predominant influence of a globally active factor on the epidemic processes of these infections. The hypothesis is substantiated, according to which the realization of this factor is a consequence of the processes of self-adjustment of biogeocenosis.

Relevance. The study of population immunity to the tick-borne encephalitis virus in endemic areas helps to identify the circulation of the virus, makes it possible to assess the dynamics of the activity of natural foci and determine the area of distribution of the virus.
The aim of this work was to analyze the level of population immunity to the tick-borne encephalitis virus in the Sverdlovsk region.
Materials & Methods. Blood plasma from the adult working population (blood donors) was examined for the presence of specific IgG antibodies to the tick-borne encephalitis virus by ELISA during 2019-2021 in five municipalities of the Sverdlovsk region, located in different landscape and geographical zones. An antibody titer of 1:800 or higher was considered protective. A statistical analysis of the obtained data was carried out.
Results. The number of individuals with a protective antibody titer in groups from various municipalities varied from 42.0 to 68.1%. Among persons who received revaccination over the past 3 years, IgG titers to TBEV of 1:800 and higher were determined in 79.8% of cases, when the vaccination period was from 3 to 6 years - in 61.3% of cases, and when the period from the last vaccination was more than 6 years – 47.5%. In the spring, specific antibodies in a protective titer were detected in 58.6% of those examined, in the fall they were detected in 55.1%. The data obtained confirm an age-dependent decrease in the level of humoral immunity to TBEV.
Conclusions. The determining factor shaping the immune structure of the population in relation to tick-borne viral encephalitis is vaccination, and a significant role in the formation of population immunity must be given to the natural pro-epidemic of the population in endemic areas, as well as age characteristics. In conditions of mass immunization of the population against tick-borne encephalitis in endemic areas, it is rational to increase the interval between revaccinations using a personalized approach with preliminary determination of the level of specific IgG in the blood serum.

Relevance. People with tuberculosis (TB) are at an increased risk of spreading parenteral viral hepatitis, including hepatitis C virus (HCV). Hepatitis C in tuberculosis patients can often be detected only as a result of laboratory tests. Some of the anti-tuberculosis drugs have a pronounced hepatotoxic effect, which can lead to severe liver damage, especially in cases of combined TB and HCV infection.
Aim. Determination of genotypic diversity and molecular genetic characteristics of HCV isolates isolated from patients infected with tuberculosis in the Tomsk region.
Materials and methods. The study was conducted on 117 blood serum/plasma samples obtained from patients infected with tuberculosis. The identified HCV isolates were genotyped by amplifying a fragment of the core gene in two-round PCR followed by determination of the nucleotide sequences of the resulting amplicons. Viral load was determined by quantitative RT-PCR.
Results and discussion. The following distribution of subtypes in the studied sample was revealed: 1b (47.0%; 95% CI: 38.2–56.0), 3a (32.5%; 95% CI: 24.7–41.3), 1a (18.0%; 95% CI: 12.1–25.8) and recombinant 2k/1b (2.5%; 95% CI: 0.9–7.2). Among the variants of subtype 1b, polymorphisms in the core gene were identified, associated with resistance to interferon treatment: among 35 isolates, the L91M mutation was detected (63.6%; 95% CI: 31.4–56.7), substitutions at position R70Q were detected in 19 isolates /H (34.6%; 95% CI: 7.6–26.1). Both substitutions were found in 11 isolates (20.0%; 95% CI: 11.5–32.3). No differences were found in the distribution of subtypes between the four age groups (under 36, 36–40, 41–45, over 45). Significant differences were revealed (Pearson's χ² = 9.38; p = 0.025) in the distribution of subtypes between the examined men and women. In men, subtype 1b predominated, in women, subtype 3a predominated and there were practically no people infected with subtype 1a, unlike male patients.
Conclusion. HCV research among tuberculosis-infected people is important for choosing the most appropriate treatment tactics for patients, preventing complications of co-infection, as well as for planning and implementing preventive measures.

Relevance. Tundra natural foci of tularemia are epizootically active. They are supported mainly by populations of endemics – ungulate and Siberian lemmings. However, studies of natural foci of tularemia in the Arctic zone were and are irregular. Recently, in connection with the intensification of economic development of the Far North, the study of the spread and circulation of natural focal infections, including tularemia, has become particularly important.
Goal Target. Assessment of epizootic activity of natural foci of tundra-type tularemia in three territories of the Arctic zone: island Shokalsky, coast of Knipovich Bay, island Wrangel.
Materials and methods. A comprehensive study of 379 raptor prey bird pellet samples in the summers of 2015 and 2019 was carried out on island Wrangel, in 2019 – on the island Shokalsky and on the coast of Knipovich Bay (Taimyr).
Results. A study of field material revealed the presence of tularemia antigen and DNA of the causative agent of tularemia in the pellets of prey birds collected throughout the surveyed territory of the Arctic. Epizootically active tundra natural foci of tularemia exist in the three surveyed territories of the Arctic zone, which are supported by populations of lemmings, the main carriers. This indicates a high risk of human infection in contact with natural foci. Confirmation of actively functioning natural foci of tularemia on the island Wrangel, as well as newly discovered outbreaks on the island Shokalsky and the coastal areas of Knipovich Bay necessitate vaccination of people permanently living and staying in these territories.
Conclusion. Natural foci of tundra-type tularemia were identified on the surveyed territories of Shokalsky Island and Knipovich Bay. Studies of pellets of prey birds and tubular bones from pellets collected on Wrangel Island confirmed previously identified active natural foci of tundra-type tularemia and the continuity of the epizootic process in this territory. Epizootics of tularemia in tundra-type foci may occur continuously due to the high ecological plasticity of the pathogen to various environmental factors and are stable. The presence and epizootic activity of natural foci of tularemia in the Far North indicate a high epidemiological risk for people visiting these territories.

Relevance. Hospital-acquired acute respiratory viral infections (ARVI) are a significant cause of high morbidity in pediatric hospitals, especially in departments for small children. To control HCAI, there is still a need for evidence-based anti-epidemic and preventive measures. Mathematical modeling is known to be an attractive approach for objectively assessing infection control measures. In this study, we demonstrate effectiveness of timely isolation of the source of respiratory infection (i.e. an infected individuals) which might be revealed in a large pediatric hospital.
Materials & Methods. We developed an agent-based model of the spread of nosocomial respiratory infection to assess the effectiveness of timely isolation of patients with ARVI. Primary data on the incidence of ARVI, the number of beds, and the frequency of infection in a multidisciplinary non-infectious children's hospital at the regional level were used. The model also implements the ability of the agent to change the department. To simulate the anti-epidemic measure, we included in the developed simulation model the execution of a local algorithm of actions by a doctor in the event of detection of a patient with ARVI (50% probability of non-compliance with isolation; almost all sources of infection are isolated; 100% decision-making, the ideal option).
Results. The maximum absolute daily increase in ARVI cases were observed in scenarios where the rules for isolating the source of infection were violated; here the median equaled 32.9 (IQR 32.4-33.4) cases, ranging from 4.0 to 34.8 cases. With an increase in the probability of isolating a patient with ARVI, the indicator decreased: with a 50% probability of isolating the source, the median was 5.7 (5-6.5); 90% probability – 3.1 (2.8-3.6); 100% probability – 2.9 (2.6-3.4) cases. According to model estimates, when comparing the departments over time, we noted their unequal involvement in the epidemic process and wave-like spread of infection. Statistically significant differences in the predicted number of ARVI cases with different probabilities of isolation were revealed.
Conclusion. We used a simulation agent-based approach to modeling nosocomial ARVI. This allowed us to correctly describe the spread of infection among patients in a children's hospital, as well as to assess the effectiveness of timely isolation of the source of infection. In our model, we took into account various options for the interaction of agents with each other. In addition, we fit importations of the infection and studied how they could facilitate the spread of the infection. The solid evidence was obtained of the effectiveness of timely isolation of the source of infection identified in healthcare settings, which can be used to justify control measures.

Relevance. During 2021 and early 2022, the prevalence of COVID-19 in the child population was 9.5%, the frequency of hospitalizations of children and adolescents increased, and fatal outcomes began to be recorded. And in 2022–2023, the proportion of children infected with COVID-19 increased to 18%. At the same time, vaccination remains the most effective way to protect against infection. Studying the safety of vaccines for the prevention of coronavirus infection is an urgent task.
Objective of the study. To study the safety of a vaccine for the prevention of a new coronavirus infection in immature animals.
Materials and methods. The study was conducted on Wistar rats (60 males and 52 females). During the study, the vaccine or placebo was administered four times with an interval of 2 weeks, in doses of 0.125; 0.25 or 0.5 ml / animal. The dynamics of body weight, animal behavior in the open field test, mass coefficients of internal organs, spermogram were assessed, and histological assessment of the reproductive system organs and the injection site was performed.
Results and discussion. No toxic effect of the KoviVak vaccine on animal behavior was revealed, positive dynamics of body weight of experimental animals were recorded. When assessing toxicity in relation to the reproductive system, no effect of placebo or vaccine on spermogram parameters and histological structure of organs was revealed. No effect of placebo and KoviVak vaccine on mass coefficients of internal organs was revealed. Histological changes at the injection site recorded in animals receiving placebo and KoviVak vaccine are explained by the mechanism of action of aluminum hydroxide, which is part of the placebo and vaccine.
Conclusion. The preclinical study on juvenile animals showed the safety of the KoviVak vaccine.

Relevance. Currently, the incidence of vaccine-controlled infections tends to increase. Despite the fact that some of them are not registered at all, the situation remains unstable and tense. Vaccination is the most effective preventive measure. The effectiveness of immunization mainly depends on achieving the necessary vaccination coverage and meeting the deadlines for their implementation. Aim. Assess the coverage of vaccination and revaccination against diphtheria, pertussis, measles, rubella and mumps in the period from 2019 to 2022. on the territory of the Russian Federation, as well as to analyze these indicators for 2022, including the timeliness of immunization within the framework of the National Calendar of Preventive Vaccinations.
Materials and methods. A retrospective epidemiological analysis of the state of vaccination coverage, revaccination and the timeliness of their implementation was carried out. Data from the Federal statistical observation form No. 6 «Information on the populations of children and adults vaccinated against infectious diseases» for 2019–2022 were used.
Results. Vaccination coverage against diphtheria and pertussis at the age of 0–1 years in the Russian Federation from 2020 is only 47.31% and 45.97% respectively. Of these, 89.31% were vaccinated against diphtheria at the age of 6 months - 11 months, 29 days, and 88,65% against whooping cough. The timeliness of vaccination against these infections is achieved only by 12 months: about 97% have been vaccinated by this age. The average levels of vaccination coverage against measles, rubella and mumps in 1 years – 1 years, 11 months, 29 days were 96,47%, 96,42% and 96,46%, respectively. The rate of timely immunization reaches 97% only by 24 months. RV1 coverage in the age group of 1 years – 1 years, 11 months, 29 days is 50.87% against diphtheria and 50.67% against pertussis, in the group of 2 years – 2 years, 11 months, 29 days – 96,38% and 96,17%, respectively. 96% were vaccinated in a timely manner by 24 months. Coverage of the second revaccination against diphtheria at the age of 6 years – 6 years, 11 months, 29 days, is on average 54.37%, in the age group of 7 years – 7 years, 11 months, 29 days – 95.88%. Coverage of RV3 at the age of 14 years – 14 years, 11 months, 29 days – 95.53%, and RV4 in the age groups of 18 years – 35 years, 11 months, 29 days, 36 years – 59 years, 11 months, 29 days, and 60 years and older in 2022, amounted to 71.2%, 78.3% and 73.9%, respectively. The coverage of revaccination against measles, rubella and mumps in 6 years – 6 years,11 months, 29 days, amounted to 96,06%, 96,02% and 96,04% respectively.
Conclusion. The analysis showed that vaccination is carried out much later than the deadlines set by the National Calendar of Preventive Vaccinations. Vaccination and revaccination coverage against diphtheria and pertussis, measles, rubella and mumps does not reach the required level of 95% in all regions, which poses a threat to the epidemiological well-being of the population. It should be noted that measles vaccination coverage does not reach 98%, thus conditions for its elimination are not created. In 2020, diphtheria, whooping cough, measles, rubella and mumps saw a decrease in vaccination and revaccination coverage due to the epidemic of COVID-19, but by 2022 coverage still did not reach the values of 2019.

Relevance. It is known that malignant neoplasms develop over a long period, under the constant influence of risk factors. Among them some biological agents, smoking and alcohol consumption are known to science. At the present stage the possibility of influence of such risk factors as sleep disorders, eating habits, obesity and overweight is being studied.
Aim. To estimate, according to the literature data, the degree of influence of some controllable risk factors on the development of malignant neoplasms of the digestive organs.
Materials and methods. The results of 130 articles conducted by Russian and foreign researchers were studied, from which 31 studies were selected that met the requirements of the selection criteria and corresponded to the objectives of the study. Based on the data presented in the studies, we analyzed relative risks, odds ratios and risk ratios of some controllable risk factors for the development of malignant neoplasms of the digestive organs.
Results and Discussion. H. pylori, which contributes to the development of gastric cancer (OR 2.39 [95% CI 1.53–3.74]), stands out among the best-known cancer risk factors. Alcohol, a group 1 carcinogen (WHO), increases the risk (OR) of esophageal cancer by a factor of 2 [95% CI 1.66–2.40], liver cancer by a factor of 1.83 [95% CI 1.39–2.40] and gastric cancer by a factor of 1.54 [95% CI 1.10–2.15]. Smoking has been shown to cause more gastric cardia cancer (Hazard ratio/КШ 4.10 [95% CI: 1.76–9.57]) than distal gastric cancer (КШ 1.94 [95% CI: 1.05–3.60]). Most of the trials also focused on the effect of dietary habits on the development of cancer. For example, consumption of 100 g/day of red and processed meat was associated with the development of colorectal cancer (OR – 1.25, [95% CI: 1.10–1.43] and OR – 1.31, [95% CI: 1.13–1.52], respectively). Meanwhile, the researchers found an association between increased BMI and the risk of esophageal adenocarcinoma (OR, 1.10 [95% CI 1.04–1.17]). Sweet tea and fresh food consumption have also been shown to play a protective role against the development of gastrointestinal cancer (OR 0.26 [95% CI 0.14–0.47] and OR 0.57 [95% CI 0.37–0.88], respectively). In addition, the literature suggests a positive effect of sleep disorders and depression on the development of cancer.
Conclusions. The presence of lifestyle risk factors such as the presence of H.pylori, consumption of fried and stale foods, daily consumption of red and processed meat of 100g or more has a significant impact on the development of digestive organ cancer. In addition, known WHO eradicable factors such as tobacco smoking and alcohol consumption have evidence of their influence on the development of digestive cancers. However, these risk factors require further in-depth study to develop systematic prevention measures. However, all the risk factors studied are manageable. If their influence is reduced or eliminated from human activity, the risk of developing digestive organ cancer is significantly reduced.

Relevance. Although the incidence of Hib infection has decreased in the last three decades, it is still significant. Even with appropriate treatment, the case-fatality rate can be as high as 5%. Up to 40% of children with infection may suffer lifelong complications. Although Hib infection is classified as vaccine-preventable, WHO and CDC do not post annual incidence information on their resources, unlike other vaccine-preventable infections. Therefore, an assessment of the global epidemic situation can only be based on the results of studies conducted in different countries.
Objective. To assess the incidence of Haemophilus influenzae type b infection in selected countries of the world and the Russian Federation against the background of the introduction of specific vaccine prophylaxis.
Conclusion. The incidence of invasive Hib infection in countries where vaccination against this infection is unavailable or has only recently been included in national vaccination programmes depends on maintaining high vaccination coverage and well-functioning surveillance systems. The persistently low incidence in all countries that have introduced Hib vaccine illustrates the success of routine vaccination programmes in providing effective protection to vaccinees and promoting collective immunity. However, the continued detection of cases of invasive forms of Haemophilus influenzae infection raises concerns that other serotypes may be displaced if mass immunisation with serotype b vaccine is carried out globally.