Introduction: The study describes existing approaches to defining public health. The state of public health affects the ability of the country to achieve strategic landmarks and national security goals. Strengthening of public health requires the development of approaches to monitoring its condition, as well as the use of practical tools aimed at the growth of this resource of the country.

Objective: To formulate the problem of studying, conceptualizing, and measuring public health.

Materials and methods: We have analyzed foreign and Russian literary sources in order to conceptualize the notion of public health and its determinants. For this, a search was made in five databases of domestic and foreign scientific literature, including Scopus, Jstor, Ebsco, eLibrary.ru, Web of Science, as well as in two search systems for Russian legal information (“Consultant Plus” and “Garant”) for the years 1972–2021. To clarify the concept of “public health”, we examined the main sociological works revealing the concepts of “society” and “health”. Special emphasis was placed on the search for public health determinants, including medical, behavioral, environmental, and economic factors. Overall, we considered 31 domestic and six foreign publications.

Results: Based on our findings, we believe that public health is a medical and social resource and the potential of the society that ensures national security and sustainable development of the country. The potential of the society should be considered as a part of public health, available to counter existing threats and challenges to the national security. We describe current approaches to developing a system of public health indicators, establishing their indicative and critical values. A decrease in the public health resource below the potential determines a violation of national security requirements.

Conclusion: Improvement of public health requires proper understanding of its determinants and key risk factors. Creation of a monitoring system will enable the use of public health supporting tools before the crisis associated with deterioration of public health due to a biological hazard erupts.

Introduction: A multifactorial analysis of the causes of morbidity and preventive measures provides an opportunity to build a risk prediction model for sickness absence in the working population, thereby reducing production and healthcare costs.

Objective: A retrospective analysis of sickness absence in workers of the Kursk Nuclear Power Plant exposed to a combination of occupational risk factors in the year 2020.

Materials and methods: We analyzed sickness absence rates in the workers in terms of the ICD-10 nomenclature based on data of the Russian Statistical Observation Form No. 16-VN and established the number of episodes of sickness absence per employee as a relative indicator independent of the size of the groups under study.

Results: The highest sickness absence rates per 100 employees were estimated for workers of the Training Center and Design and Technology Department (73.1 episodes each), the Hydroshop (68.6) and Transportation Department (65.5). In the Radioactive Waste Treatment Shop and the first and second Reactor Shops, these rates were 53, 43.9, and 33.9 per 100 employees, respectively. The mean duration of an episode of sickness absence in all divisions of the nuclear power plant was 13–15.4 days and its most frequent causes were, similar to the Kursk Region and the Russian Federation as a whole, diseases of the respiratory and musculoskeletal systems, injuries and poisonings.

Study limitations: Due to the specifics of the data collection form used, we had no information about the whole aggregate of episodes and days of sickness absence.

Conclusions: It is important to develop a risk-based approach in occupational medicine. To establish a cause-and-effect relationship for loss of health among nuclear industry workers, we propose to create a digital platform (a digital twin of an employee) enabling prediction of the time, cause, risk of a disease and/or disability, and prerequisites for its mitigation.

Introduction: The modern educational environment involves the use of various electronic devices generating physical hazards.

In addition to the widespread use of these devices, other physical factors of the school environment also affect schoolchildren’s health. However, the impact of the combined exposure to physical factors of various nature on the regulatory systems of the body has been studied insufficiently so far. However, the influence of a complex of physical factors of various nature on the regulatory systems of the body has not been sufficiently studied.

Objective: To evaluate the features of the immune and neuroendocrine status of schoolchildren exposed to heterogeneous physical factors of a non-ionizing nature at school and to analyze the relationship between the studied physical factors and changes in the parameters of regulatory systems.

Materials and methods: The exposed group included 144 students of a gymnasium from the city of Perm and the unexposed (reference) group consisted of 114 schoolchildren from the town of Kungur, Perm Region. We measured physical factors of the school environment, including noise, artificial illumination, electromagnetic radiation, and air ion concentrations affecting elementary, secondary, and high school students from both groups and compared the results with respective permissible levels. The indicators of immune (CD-phenotyping, phagocytic activity of leukocytes, concentrations of immunoglobulins and cytokines) and neuroendocrine (TSH, free T4, and cortisol) systems were established and compared. Mathematical models were calculated and analyzed in order to find the links between the exposure to physical factors under study and the parameters of the immune and neuroendocrine systems.

Results: The indoor air study showed differences in the number and charge of air ions between the gymnasium with its numerous e-learning tools and the school of comparison. The study of the immune and neuroendocrine systems in the exposed group revealed age-related changes in the expression of lymphocyte subpopulations, moderate changes in humoral and phagocytic parameters, an imbalance in the expression of pro- and anti-inflammatory cytokines and hormones. The construction of logistic regression models allowed us to establish the link between the parameters of electromagnetic radiation in the school environment and changes in the immune status of students (CD19+ and CD3+CD8+ lymphocytes).

Conclusion: The study demonstrated a number of changes in the regulatory systems of schoolchildren associated with the impact of physical factors of the school environment.

Background: Modern children are noted for increasing mobile Internet usage, during which the electromagnetic field exposure is aggravated by the exposure to the phone screen light, both affecting children’s well-being. The relevance and purpose of this study have been determined by insufficient knowledge of effects of this combined exposure and the lack of data on the patterns of mobile Internet usage detrimental to younger schoolchildren’s health.

Objective: To assess the impact of mobile Internet usage on the well-being of elementary students and to establish its parameters posing risks of children’s ill-being.

Materials and methods: In 2017–2019, a cross-sectional study of 140 Moscow first to fourth graders was conducted using questionnaires to establish the parameters of smartphone use for voice calls and access to mobile Internet as well as the frequency of health complaints and neurological history. In addition, the energy flux of electromagnetic fields generated by the children’s cell phones was measured. In 112 students with a normal neurological history, of which 77 used and 35 did not use mobile Internet, the applied statistical methods revealed the parameters of mobile Internet usage posing risks of ill-being, i.e. having certain health complaints several times a week.

Results: Mobile Internet usage was associated with sleep dissatisfaction in the children (OR = 6.81; 95 % CI: 1.91–24.22), which occurred when the monthly Internet usage exceeded 8.62 hours and a session length was more than 10 minutes. Daily Internet usage increased the risk of forgetfulness (OR = 5.23; 95 % CI: 1.43–19.19) while higher levels of smartphone radiation correlated with both sleep dissatisfaction and forgetfulness. A low intensity of mobile Internet usage (less than 17.74 hours a month) was associated with low mood in the study population.

Conclusion: To prevent ill-being, younger students shall be advised to exclude mobile Internet usage or to limit it to 8.62 hours per month.

Background: Organization of healthy and balanced nutrition for children undergoing orthodontic treatment should have a compensatory and preventive focus.

Materials and methods: A 24-hour dietary recall was used to assess actual nutrition of 57 adolescents aged 13–14 years divided into two groups: cases wearing orthodontic bracket systems and controls having no dentoalveolar anomalies. A comparative analysis of qualitative and quantitative parameters of the diet was carried out based on current regulatory documents.

Results: We observed an imbalance in the intake of macro- and micronutrients in the diets of all adolescents caused by an imbalanced food set and being more pronounced in those undergoing orthodontic treatment. The diet of the controls was noted for an adequate daily calorie intake (94.0 % of the recommended value) as opposed to the case group (78.1 %). The diets in the control group were deficient in total protein (94.6 %) and carbohydrates (89.4 %) but excessive in fats (104.6 %). In the case group, the dietary intake of macronutrients was, on the average, 78.3 % of the norm. Restrictions on consumption of certain foods in the diet of adolescents with braces led to a significant deficiency in meat consumption (66.3 % of the recommended value), fish and seafood (37.6 %), eggs (55.0 %), bakery products (45.6 %), potatoes (80.1 %), fruits (51.6 %), and vegetables (51.0 %).

Conclusion: Braces used for orthodontic treatment of dentoalveolar anomalies in some patients become a risk factor for both malnutrition and demineralization of tooth enamel in adolescents. It is therefore necessary to develop recommendations for healthy nutrition of pediatric patients undergoing orthodontic treatment.

Background: At present, one of the critical hygienic tasks is to study the potentials of using recycled polymer materials in the manufacturing of modern children’s products and ensuring their chemical safety. Secondary polymer materials are various polymer wastes that have lost their consumer properties but have retained their technological characteristics enabling their reuse as raw materials. A number of significant initiatives on the use of recycled polymers in the production of goods for children and adolescents are already being implemented worldwide.

Objective: To assess safety of recycled polymer materials used for the manufacturing of children’s products, including toys.

Materials and methods: We studied 96 samples of primary and recycled polymer materials based on polyethylene terephthalate and high-density polyethylene by performing 4,186 tests using 31 chemical, physical, organoleptic, and toxicology methods.

Results: We obtained the results of a comparative study of primary and recycled polymer materials that included determination of migration of 48 volatile and semivolatile organic compounds to the air of environmental (climate) chambers and an aqueous model environment; migration of cadmium, lead, chromium, arsenic, selenium, barium, antimony, and mercury into distilled water; toxicity indices in the air of climate chambers and in aqueous extracts; organoleptic parameters (odor of the sample, odor and taste of the aqueous extract); changes in pH and permanganate index of aqueous extracts, and color fastness to saliva and sweat. Under standard conditions of sample preparation and under all aggravated conditions (e.g., high temperature, long-term exposure, etc.), nonconforming products were not found; in some samples, the levels of chemicals tested were below the limits of detection. We observed no differences between the results of testing primary and recycled polymer materials.

Conclusions: We established that the tested samples of recycled polymers based on polyethylene terephthalate and high-density polyethylene are chemically stable and can therefore be recommended for use in the manufacturing of products for children and adolescents on equal terms with primary polymer materials.

Introduction: An urgent hygienic problem in the regions with intensive industrial development is the persistence of ambient air pollutants and their adverse health outcomes in the population leading to higher incidence rates of non-communicable diseases and their chronicity.

Objective: To substantiate the relationships between high blood levels of copper, nickel, and chromium and biomarkers of their adverse effects on blood, respiratory and immune systems for the tasks of early detection and prevention of poor health outcomes of the combined inhalation exposure to copper, nickel and chromium oxides on the example of the adult population at risk.

Materials and methods: We carried out a hygienic assessment of ambient air quality in residential areas and analyzed general population incidence and prevalence for 2016–2020. We also examined the health status of women of reproductive age environmentally exposed to nickel, chromium and copper oxides in the area of residence and of relatively unexposed controls. About 5,000 chemical, clinical, immunological, and biochemical tests were done in 2022.

Results: We established associations between higher blood levels of copper, nickel, and chromium and changes in the indicators of adverse health effects. Biomarkers of nonspecific and specific sensitization, chronic inflammation accompanied by an imbalance in the humoral and cellular immunity were hyperproduction of eosinophils in the nasal mucus, blood lymphocytes, specific IgG to copper, a decrease in the phagocytic index and number; lower ferritin marked disorders of iron homeostasis, higher malondialdehyde indicated induction of oxidative processes, and a decrease in antioxidant activity gave evidence of depletion of the total antioxidant activity.

Conclusions: It is expedient to use our findings for early detection and subsequent substantiation of targeted measures aimed at preventing disorders of the respiratory and immune systems, blood, and certain disorders involving the immune mechanism, etiopathogenetically related to the combined exposure to the metal oxides tested.

Introduction: The COVID-19 pandemic has shown the importance of non-specific measures of infectious disease prevention, including the use of respiratory protective equipment. Despite the improvement in the epidemiological situation and gradual lifting of public health restrictions, some people keep wearing face masks.

Objective: To analyze the use of respiratory protective equipment in accordance with COVID-19 face mask requirements and after the end of the mask mandate among medical students in Moscow.

Materials and methods: The questionnaire-based survey was conducted in two stages in March 2021 and in March–April 2022 among 988 and 830 third year students of the Institute of Clinical Medicine, Sechenov University, respectively, to collect data on socio-demographic characteristics, the practice of wearing face masks in public places, and the incentives to use them. The observational study was carried out in March 2022 among 816 Russian and 96 foreign students by counting those wearing face masks in the classrooms.

Results: We established that 97.5 % of the respondents used respiratory protective equipment during the period of restrictive public health measures. The main reasons for doing that were a mask mandate due to coronavirus and the necessity of personal contacts with other people. The survey showed that masks were most often used in health facilities, supermarkets, pharmacies, subway, and at the university. During the first two weeks after abolishing mandatory wearing of face masks, 18.3 % of all the respondents continued their use, mainly out of concern for other people’s health, of whom 9.9 % and 89.6 % were Russian and foreign medical students, respectively. The second survey demonstrated that 7.2 % of the Russian medical students kept wearing masks in some settings later on. In case of yet another increase in the COVID-19 incidence, 97.6 % of the respondents intend to use respiratory protective equipment and 74.7 % of them plan to recommend this preventive measure to their relatives.

Study limitations: Due to the fact that only medical university students aged 20 to 23 took part in the research and in view of the short time period that had elapsed since lifting of masking requirements, it is of interest to survey various age and social population groups in a longer-term perspective.

Conclusions: Medical students continue using respiratory protective equipment after the restrictions are lifted, mainly to protect others.

Introduction: Congenital heart defects are one of the most common malformations. Almost 50 % of patients with congenital heart defects require cardiac surgery. Nosocomial infections strongly influencing the effectiveness of postoperative rehabilitation remain among the major problems of modern health care.

Objective: To establish risk factors for infectious complications in children with congenital heart defects after cardiac surgery.

Materials and methods: In 2014 to 2021, we conducted a case–control study of 603 patients under the age of 18 with congenital heart defects who underwent 643 cardiac surgeries at the perinatal center. The case cohort included 134 children of both sexes having infectious complications while the control cohort included 469 children of both sexes showing no signs of nosocomial infections after cardiac surgeries. We assessed the role of endogenous and exogenous risk factors for postoperative infectious complications and the relationship between the exposure and the outcome based on the odds ratio. Testing for significance of differences was performed by hypothesis assessment with the calculation of the p-value and estimation of confidence intervals.

Results: The incidence density of healthcare-associated infections was 15.6 (13.26–18.32) per 1,000 patient-days. The most significant endogenous and exogenous risk factors were identified.

Conclusions: The established predictors of infectious complications indicate the need for a risk-based approach to prevention of nosocomial infections in pediatric cardiac surgery.

Background: The hepatitis C virus is known for its high spontaneous mutation rate and genetic heterogeneity. Genotype distribution varies greatly between different regions of Russia. This phenomenon reflects autonomous nature of the epidemic process of the hepatitis C infection.

Objective: To investigate and analyze the diversity of genetic variants of the hepatitis C virus currently circulating in the city of Nizhny Novgorod.

Material and methods: Official hepatitis C incidence data for the Nizhny Novgorod Region were analyzed retrospectively. From the blood serum bank, we obtained 142,254 serum samples from examined outpatients and patients admitted to hospitals for noninfectious diseases. Laboratory testing included detection of the following markers for hepatitis C virus infection: serum anti-HCV IgM and IgG, antibodies to structural and non-structural viral proteins. A part of seropositive samples was tested for HCV RNA and genotyped by real-time PCR.

Results: We observed stabilization of the trend in the incidence of acute hepatitis C in Nizhny Novgorod and a steady decrease in the incidence of newly diagnosed chronic hepatitis C. The antibody serology tests showed that the prevalence of anti-HCV was 3.1 ± 0.1 per 100 examined persons. HCV RNA was detected in 1.9 ± 0.1 % of adults, the most affected being those aged 40–49 years. Subtypes 1b and 3a prevailed while subtype 1a, genotype 2, and mixed variants were rare.

Conclusion: Introduction of advances in genetic diagnosis into the system of epidemiologic hepatitis C surveillance is determined by the relevance of conducting a comprehensive examination of people infected with HCV in order to monitor circulation of hepatitis C virus genotypes/subtypes and to understand the evolution and epidemiological features of the disease in different areas.

Introduction: It is obvious that effective investigation of norovirus outbreaks is impossible without the use of methods enabling differentiation of pathogen genotypes, the principal of which is the determination of the type of capsid and polymerase based on sequencing data. Yet, unstable operation of international services for assessment of norovirus genomes from a number of IP addresses located in the Russian Federation has been noted recently, which may affect the efficiency and promptness of investigation of norovirus outbreaks in our country.

Objective: To develop domestic software for genotyping of noroviruses and further assessment of genetic diversity of noroviruses identified in the year 2022 in the Rostov Region.

Materials and methods: The materials for the study were stool samples from 210 patients with symptoms of gastrointestinal infections from temporary accommodation centers for refugees and children’s centers. The study population included patients aged 1 month to 74 years with symptoms of acute bowel infections. Detection of the pathogen RNA was carried out using a reagent kit AmpliSens® OKI screen-FL (Moscow, Russia). Fragment sequencing was performed using a genomic analyzer SeqStudio (Thermo Fisher, USA). The authors’ software was developed in the Java and Python programming languages.

Results: We developed a domestic NoroNetRus software allowing determination of the type of capsid and polymerase of noroviruses based on sequencing data. The software is free of charge and available online at http://antiplague.ru/noronetrus. The fragment analysis of VP1 gene sequences for 25 norovirus samples showed that they belonged to three different genotypes (GII.4 Sydney, GII.10, and GII.17), and the genotype GII.10, in its turn, was distributed between two different clusters. Our findings indicate the existence of at least four different sources of infection.

Conclusion. The data obtained indicate the circulation of at least four different genovariants of the causative agent of norovirus infection in the Rostov Region in 2022.

Background: For small rivers, the monitoring carried out by the Center for Hygiene and Epidemiology in the Voronezh Region is insufficient due to the limited number of water sampling points and the assessment of its quality only by a number of priority chemical and microbiological indicators.

Objective: To assess the state and structure of macrozoobenthos communities of the Usman River affected by local anthropogenic contamination.

Materials and methods: The analysis of the river water quality included testing of safety and chemical indicators by laboratory research methods. Surveys of the macrozoobenthos of the river were conducted as part of the research expedition in September–October 2021. The dominant information structure of bottom communities from the upper reaches to the mouth of the river was analyzed, after low water and pollution of the upper reaches of the river by industrial and household effluents in the 2020/2021 winter period. We established the main types of communities, identified dominant species, and analyzed indicators of the information structure.

Results: Our findings confirm a strong destructive effect of organic discharges of “Ovoschi Chernozemya” LLC [Vegetables of the Black Earth Region] and “Vodokanal” wastewater service of the town of Usman on the bottom communities of the river, where, in comparison with the background, near the village of Krasnoe, we observed a change of community types and a multiple decrease in species diversity, abundance, biomass, stability, suppression of information diversity, and “jump” in entropy, indicating either degradation or a period of community restructuring.