The study assessed the economic damage in Moscow and the Russian Federation for 2024, resulting from 243 and 3,821 cases of surgical site infections, 431 and 7,506 cases of lower respiratory tract infections, and 13 and 482 cases of urinary tract infections, respectively. Calculations were made using compulsory medical insurance rates and clinical guidelines. A weighted average of direct treatment costs per case of varying severity was calculated. The highest costs were found to arise in the treatment of severe lower respiratory tract infections. The economic damage from the studied forms of infections associated with the provision of medical care for Moscow amounted to 134.2±1.9 million rubles, and for the entire Russian Federation – 2,679.4±5.4 million rubles. Only for registered cases. Taking into account the identified disparities in the registration of HAI cases of at least 1:100, the minimum direct damage from all HAI cases in 2024 will start from 533 billion rubles, and the indirect damage from lost GDP due to disability will start from 776 billion rubles. The proposed assessment method allows us to identify the costliest nosological entities and prioritize HAI prevention.

   Clostridioides difficile is a leading causative agent of nosocomial antibiotic-associated diarrhea. Spore formation, resistance to alcohol-based antiseptics, and the fecal-oral transmission route complicate infection control in high-risk departments.

   Objective. To study the prevalence, structure, and risk factors of C. difficile infection in a multidisciplinary hospital to optimize epidemiological monitoring and preventive measures.

   Materials and methods. The analysis includes the results of stool samples from 5,209 patients tested for C. difficile toxins; C. difficile infection (CDI) was confirmed in 860 cases. Epidemiological, enzyme immunoassay (EIA), and statistical methods of investigation were applied.

   Results. Clostridioides difficile- infection prevails in intensive care, oncology, transplantation, nephrology, and gastroenterology departments. Antibiotic therapy remains the primary trigger of the disease. The COVID-19 epidemic led to an increase in nosocomial incidence, while an influx of patients admitted to the hospital with pre-existing CDI symptoms has been observed since 2021. Bone marrow transplant recipients are the most vulnerable cohort to recurrent infection. In gastroenterological patients, CDI manifests within the first 48 hours, requiring differential diagnosis with exacerbation of inflammatory bowel diseases. The frequency of CDI in nephrology, cardiology, and oncology patients exceeds that in surgical departments. The mortality rate among patients tested for C. difficile toxins was 15.3 %, and the share of CDI in the structure of hospital mortality reached 31.5 %.

   Conclusion. The biological properties of C. difficile significantly complicate the localization of outbreaks and containment of infection spread in high-risk departments. Along with antibiotic therapy, patient age, comorbidity, and invasive interventions shape a specific epidemic process in each department. During the COVID-19 epidemic, an activation of the CDI epidemic process was noted, particularly among bone marrow recipients. A comprehensive set of measures is required to reduce morbidity, including hand hygiene with soap, strict patient isolation, the use of sporicedal chlorine-containing disinfectants, and continuous training of medical personnel.

   Introduction. Infrastructural and population factors of the COVID-19 pandemic have a significant impact on the functioning of public health systems. Studying the multifactorial impact that the COVID-19 pandemic has had and continues to have on the health and lives of the population, including medical workers and other risk groups, and evaluating the effectiveness of preventive measures is an important task of modern epidemiology.

   Objective. To determine the list of urgent tasks, functions and anti-epidemic measures facing the healthcare system and evaluate the effectiveness of their implementation during the COVID-19 pandemic.

   Materials and methods. Information and analytical methods were used to study the features of the epidemic process of the new coronavirus infection, the functions and tasks facing the healthcare system during the COVID-19 pandemic. The search was performed in five databases of Russian and foreign scientific literature, including Scopus, Jstor, Ebsco, eLibrary.ru, Web of Science, as well as in two search systems for regulatory legal information relevant to Russia (Consultant Plus and Garant), for the period 2020–2024. Based on the study of domestic and international data, an analysis of legislative and regulatory acts, scientific research results was carried out; recommendations of the World Health Organization (WHO) and national health systems on the implementation of a set of anti-epidemic measures to combat COVID-19 were systematized. Overall, 12 domestic and 35 foreign sources were reviewed.

   Results. It has been confirmed that the use of new algorithms for preventive measures and medical care in conditions of an intensive epidemic process is a priority task of the healthcare system. Urgent public health measures in the context of a pandemic are the identification and isolation of patients, as well as the early adoption of physical distancing measures to break the chains of transmission of the infectious agent.

   Conclusion. Studying the genesis and factors contributing to the spread of COVID-19 is extremely important for developing effective strategies to contain the infection and prevent its further spread in epidemic foci.

   Background. The reproductive health is one of the determining factors of social well-being and public health. Sexually transmitted infections (STIs) are a common cause of various urogenital diseases. Preventive medicine, including early diagnosis of diseases, plays a significant role in maintaining reproductive health at the state level.

   Objective. Assessment of the frequency of STI detection in women of reproductive age in order to form scientifically sound proposals for improving screening measures.

   Materials and methods. The study includes the results of analyzes from 333482 women of reproductive age who applied to various medical organizations in the Moscow region in 2014–2023 to detect STI DNA by real-time PCR. The assessment of the age groups most susceptible to STIs was carried out using a logistic regression model.

   Results. Chlamydia trachomatis DNA was detected in 1.8 % of samples, Neisseria gonorrhoeae – 0.2 %, Mycoplasma genitalium – 0.7 %, Trichomonas vaginalis – 0.4 %. A statistically significant increase in the chance of developing C. trachomatis was shown in women aged 18–29 years, N. gonorrhoeae and M. genitalium aged 18–25 years, T. vaginalis at 38–45 years (p < 0,005).

   Conclusion. STIs are important factors influencing the development of diseases of the genitourinary system. In the Moscow region, DNA of STI pathogens was found in 2.9 % of women 18–45 years old. The age risk groups for C. trachomatis are 18–29 years old, N. gonorrhoeae and M. genitalium are 18–25 years old, and T. vaginalis is 38–45 years old. A systematic approach to the diagnosis and treatment of STIs will reduce the incidence of STIs, complications of the genitourinary system and improve reproductive health.

   Introduction. Infections affecting reproductive health remain a global social problem that has a negative impact on women's health, especially when left untreated.

   Objective. To assess the frequency of detection of genital pathogens DNA and socio-behavioral characteristics in women living in the Republic of Sakha (Yakutia).

   Materials and methods. Vaginal mucosal secretion samples from 334 women aged 18–65 who visited an obstetrician-gynecologist at State Autonomous Institution of the Republic of Sakha (Yakutia) «RCH № 3» in 2024–2025 were analyzed. DNA extraction and amplification were performed using reagent kits manufactured by the Central Research Institute of Epidemiology.

   Results. DNA of sexually transmitted infection (STI) pathogens was detected: Neisseria gonorrhoeae – in 0.2 % of samples, Chlamydia trachomatis – 3 %, Mycoplasma genitalium – 4.5 %, Simplexvirus humanalpha 1–0.6 %, and Simplexvirus humanalpha 2–4.5 %. Among vaginal microbiota disorders, the most frequently detected were: bacterial vaginosis – 23.1 % of women; Candida fungi –9.8 %; bacterial vaginosis combined with Candida fungi – 7.9 %. Statistically significantly more DNA of STI pathogens was detected in women without a regular sexual partner compared to women with a regular sexual partner (p=0.03) and in women with a history of casual sex compared to women without (p=0.02). There were no statistically significant differences in the frequency of detection of STIs depending on the level of education, the presence of complaints and previously identified cases of diseases.

   Conclusion. In the study group, 11 % of women tested positive for STI pathogens, and 49 % tested positive for microorganisms associated with vaginal microflora disorders. Early detection of urogenital diseases can help prevent serious complications of the female reproductive system, which is especially important in remote areas of the Russian Federation.

   Introduction. The COVID-19 epidemic has had a significant impact on all spheres of life of the population, which affected the incidence of chronic non-communicable diseases.

   The purpose of the study: to study the features of the incidence of chronic non-communicable diseases of the adult population of the metropolis in the pre-epidemic period and in the context of the spread of COVID-19.

   Materials and methods. A retrospective epidemiological analysis of the incidence was carried out according to the data of forms No. 12 and No. 30 on the territory of the municipal polyclinic of St. Petersburg serving the adult population. The epidemiological study includes three periods: a pre-epidemic (2017–2019), an epidemic period (2020–2022) and a decrease in the incidence of COVID-19 (2023–2025). The analysis includes data on diseases with a first-time diagnosis according to disease classes by ICD-10.

   Results and discussion. During the COVID-19 epidemic, there was a statistically insignificant increase in the incidence of chronic non-communicable diseases among the adult population. During the period of a decrease in the intensity of the COVID-19 epidemic process, an increase in the incidence was established compared to the period preceding the epidemic, blood diseases by 8 times, the circulatory system by 5 times, the endocrine system by 4.7 times, the digestive system by 3.9 times, the nervous system by 2.7 times, neoplasms by 2.4 times, the genitourinary system by 2 times, the differences are statistically significant (p < 0.05). Among diseases of the circulatory system, an increase in the number of newly diagnosed diseases associated with an increase in blood pressure was revealed, among respiratory diseases – the incidence of asthma, among diseases of the endocrine system – type 2 diabetes mellitus. An increase in the incidence is observed among the working-age population and especially among people over working age.

   Conclusion. During the spread of COVID-19, there is an increase in the incidence of chronic non-communicable diseases, which may be associated with the improvement of the system of preventive measures and the negative impact of infection caused by SARS-CoV-2.

   The aim of this study was to epidemiologically characterize medical emergencies and analyze the detection of hepatitis B markers in blood and blood component donors at the regional level.

   Materials and methods. Descriptive epidemiological study with data processing in Excel, 2016. The frequency, structure, and causes of emergency situations among healthcare workers, as well as information on the frequency of detection of HBsAg and/or anti-HBc totals in donors of blood and its components for 2015–2024 in the Republic of Tatarstan, were analyzed.

   Results. From 2015 to 2022, a downward trend in the incidence of chronic HBV infection was observed (9.2 and 4.1 per 100,000 population, respectively), while in 2023–2024, an upward trend was observed (7.1 and 10.8, respectively). Positive HBsAg is detected in the serum of 2–12 blood
and blood component donors annually, representing 0.1–0.4 cases per 1,000 donors; anti-HBc total is detected in 64–606 donors, representing 2.3–26.2 cases per 1,000 donors. Of all registered emergency situations, 75–90 % were medical, with nursing staff accounting for the majority of casualties (57.1 %), and needlestick injuries (74.4 %) being the primary cause.

   Conclusion. The persistent prevalence of HBV infection markers in blood and blood component donors and ongoing workplace emergencies in healthcare organizations highlight the importance of further research into the diagnosis, treatment, and prevention of hepatitis B.

   The objective. To increase and assess the awareness of Sechenov University students about hepatitis C using an educational video and a specially prepared questionnaire.

   Materials and methods. An educational video and a questionnaire consisting of nine questions were prepared. A survey was conducted before and after viewing, the results were analyzed. Sample population: 155 students in their first to sixth years at the Institute of Sechenov University.

   Results. All respondents were divided into levels of awareness about hepatitis C. The survey was conducted before and after viewing the educational video. Before viewing, a high level of awareness was determined in 45.8 % of respondents; an average level in 36.8 %; and a low level in 17.4 %. After viewing: a high level of awareness was determined in 61.9 % of respondents; an average level in 31.6 %; and 6.5 % had a low level of awareness.

   Conclusions. The results of the survey showed that the awareness of Sechenov University students about hepatitis C increased after watching the educational video, but there was still a need for further education on this issue.

   Acute intestinal infections (AII) are among the most common infections and are caused by a wide range of pathogens. In recent years, polymicrobial AIIs have been increasingly diagnosed; however, their epidemiological characteristics remain poorly understood.

   Objective. To identify the epidemiological characteristics of polymicrobial AIIs diagnosed in pediatric and adult infectious disease hospitals.

   Materials and methods. A retrospective analysis of AII cases from January 1, 2023, to December 31, 2025, identified in patients at pediatric and adult infectious disease hospitals in St. Petersburg.

   Results. The proportion of polymicrobial AIIs (including only associations of bacterial and/or viral intestinal pathogens) among cases with an established etiology was 8.58 %, 6.32 %, and 12.69 % (p < 0.01) in the adult and pediatric infectious disease hospitals, respectively. Viral and bacterial acute intestinal infections were the most frequently detected (67.65 %, 57.45 %, and 80.21 %, respectively, p<0.05). Among the associations, the most frequently recorded were Norovirus with Rotavirus (29.18 %) and Norovirus with Campylobacter sp. (17.5 %) in the adult infectious diseases hospital, Rotavirus with Campylobacter sp. (25.9 %), and Rotavirus with Salmonella sp. (20.1 %) in the pediatric infectious diseases hospital. The highest number of adult hospitalizations with polymicrobial acute intestinal infections is observed in January and August, while the highest number of children hospitalized with polymicrobial acute intestinal infections is observed in August-December.

   Conclusion. Polymicrobial acute intestinal infections are detected in children twice as often as in adults. The epidemiological features of the incidence of polymicrobial acute intestinal infections include the predominance of Norovirus in associations in adults and Rotavirus in associations in children. Significant differences were revealed in the intra-annual dynamics of acute intestinal infections of viral-viral, viral-bacterial and bacterial-bacterial etiology both among themselves and among children and adults.

   Objective. To characterize the epidemiological and microbiological features of fungal colonization and infections in neonates.

   Materials and methods. An observational epidemiological study was conducted. It comprised a retrospective, single-center analysis of microbiological surveillance data from 2001 to 2025, a prospective, single-center study of fungal colonization and infections from 2021 to 2025, and a multicenter analysis of clinically significant fungal infections in neonates across three hospitals in Saint Petersburg.

   Results. During 2021–2025, 376 cases of fungal infections in neonates were identified in three hospitals. Outbreak-associated cases predominated and accounted for 82.2 % of all infections. Вloodstream infections and catheter-associated bloodstream infections accounted for 85 %. The leading pathogen was Candida parapsilosis, responsible for 40 % of infections. Compared with C. albicans, C. parapsilosis was more frequently associated with invasive infections, bloodstream infections, and catheter-associated bloodstream infections. Positive correlation between the rate of episodes detected on admission and hospital-acquired episodes was revealed, with C. albicans predominating in both groups (r = 0.76). In the prospective, single-center study, colonization accounted for 89.0 % of cases, while 60.3 % were hospital-acquired. Malassezia furfur was detected in 6.1 % of cases and was associated with late hospital-acquired detection.

   Conclusions. Fungal colonization and infections in neonates demonstrate species-specific epidemiological patterns. Hospital spread of C. albicans was mainly associated with strains introduced by colonized patients on admission. In contrast, C. parapsilosis showed hospital transmission and accounted for a substantial proportion of invasive infections and outbreak-associated cases. Detection of M. furfur and other rare yeasts highlights the need for expanded etiological diagnostics in high-risk neonatal units.

   Objective. To find out reasons of nosocomial measles transmission in the multidisciplinary pediatric hospital.

   Materials and methods. He study included 180 patients, 158 caregivers of hospitalized children, and 73 healthcare workers of a pediatric hospital. Measles case identification was performed using a standard case definition. Laboratory confirmation was carried out using enzyme-linked immunosorbent assay to detect measles-specific IgM and IgG antibodies in blood serum, and polymerase chain reaction were used for differential diagnosis of respiratory viruses (nasopharyngeal swab).

   Results. A 9-month-old female patient presented with a typical clinical picture of measles; nevertheless, the diagnosis was established 5 hours after hospitalisation. Contact persons (patients, parents/guardians) were identified using the «Ariadna» medical information system, healthcare workers were identified according on departmental staffing records. Contacts were identified among other hospitalized persons from March 25, 2024, to March 30, 2024, in the same wards or adjacent rooms sharing a common ventilation system with the infected patient. Due to delayed diagnosis, 411 contacts were identified, and 4 patients were re-hospitalised with a diagnosis of measles.

   Conclusion. Viral exanthems require heightened diagnostic vigilance, particularly during epidemic rises in incidence of highly contagious infections such as measles. Improvement of patient routing algorithms with exanthematous diseases in multidisciplinary hospitals is warranted.

   Enterovirus infection is widespread both in Russia and in neighboring and non-neighboring countries.

   The relevance of its study is due to its global spread, the risk of introducing new pathogen isolates into the Russian Federation due to high migration and tourism activity, as well as the pathogen's high contagiousness and resistance in the environment, the diversity of transmission mechanisms and routes, the lack of specific prevention, outbreaks with varying degrees of severity, and the impact on all segments of the population, especially children and newborns (the mortality rate in this group reaches 30–50 %).

   The aim of the study was to analyze the factors contributing to the emergence and spread of enterovirus infection outbreaks and to identify the clinical forms of the disease most susceptible to outbreak development.

   Materials and methods. Using information from statistical forms available on the official websites of US and European health organizations and the WHO, we examined the pathogenetic aspects of enterovirus infection, epidemiological risks, and age-related characteristics.

   Results and discussion. Diagnosis is challenging due to the diversity of clinical forms: the rate of misdiagnosis reaches 67 %. The study highlights the need to improve early recognition of the disease and illuminates the complex interaction of epidemiological and clinical factors contributing to outbreaks.

   Conclusions. The high genetic variability of enteroviruses causes a wide range of clinical manifestations, from asymptomatic carriage to severe forms such as serous meningitis. PCR is the preferred method for genotype identification and genome sequencing. Molecular epidemiological monitoring is carried out by Rospotrebnadzor. Improving health literacy among tourists visiting regions with warm climates is important. Optimizing epidemiological surveillance includes creating a unified disease monitoring system, identifying risk zones, and analyzing dominant serotypes.