Relevance. Toxocariasis is a geohelminthiasis caused by the larval stage of nematodes of the genus Toxocara, characterized by ubiquitous spread. The disease is socially significant, as it reflects the level of social and hygienic well-being of the population.

Aim. study was to determine the actual epidemiological situation of visceral toxocariasis in Russia based on a comprehensive analysis of official statistics, seroepidemiological, and sanitary-parasitological studies.

Materials and Methods. An analysis of the epidemiological situation of toxocariasis in the Russian Federation for 2024 was conducted using data from the Unified Information and Analytical System «Personalized Accounting of Infectious Diseases» module and 865 epidemiological survey cards from toxocariasis outbreaks received by the Reference Center for Monitoring Larval Helminthiasis. Evaluation of the obtained data from the seroepidemiological survey of conditionally healthy individuals and sanitary-parasitological studies of epidemiologically significant environmental objects conducted in several regions of the Russian Federation in 2024.

Results. Problem areas were identified where significant discrepancies were observed between the registered incidence rate, the seroprevalence of the population for T. canis, and the degree of contamination of epidemiologically significant environmental objects.

Background. Streptococcus agalactiae (Group B Streptococcus, GBS) remains a leading cause of severe perinatal infections. The key features of S. agalactiae population in Russia remain underexplored, necessitating comprehensive molecular surveillance.

Aim. This study aimed to perform a comprehensive analysis of the serotype distribution, clonality, and prevalence of genetic virulence determinants in S. agalactiae isolates recovered in Russia in 2021–2024.

Materials and Methods. We analysed 72 non-invasive S. agalactiae isolates. The isolates were collected in Northwestern Federal District between 2021 and 2024 from patients (30 males and 42 females, aged 18–55 years). We recovered the isolates from vaginal, cervical, and urethral swabs, urine, prostate secretion, and semen. We performed initial species identification by standard bacteriological methods, latex agglutination and PCR. The isolates were whole-genome sequenced. We used bioinformatic analysis to derive serotypes, multi-locus sequence types (ST), clonal complexes (CC) and virulence genes from genome data.

Results and Discussion. Our data revealed that serotypes V (34.7 %), Ia (22.2%), and III (22.2 %) were predominant, collectively accounting for 79.1 % of the isolates. The isolates exhibited high genetic diversity, comprising 22 sequence types (STs) grouped into 7 clonal complexes (CCs). The dominant CCs were CC1 (29.2 %), CC23 (23.6 %), CC19 (19.4 %), and CC17 (12.5 %). The most prevalent pilus genotype was PI-1+PI-2a1 (36%). The genes encoding surface protein Srr1 and Alp-like proteins were detected in 80.6% and 58% of isolates, respectively. The isolated of hypervirulent CC17 complex carried hvgA, srr2, and rib genes.

Conclusion. We found that the S. agalactiae isolates exhibited high genetic diversity, with predominant serotypes V, Ia, and III and clonal complexes CC1, CC23, CC19, and CC17. Our analysis revealed a prevalence (12.5%) of the hypervirulent CC17 clone, confirming the circulation of high-risk strains associated with neonatal invasive disease. Our results indicate that a hexavalent conjugate vaccine would likely cover a majority of the circulating strains. We identified specific virulence gene profiles and their association with certain clonal complexes. Our results suggest that the revealed virulence factors are promising targets for serotype-independent vaccine development.

Relevance. A key feature of the modern pertussis epidemic is the increasing incidence of the disease against the backdrop of years of mass vaccination: since the mid-1950s, with whole-cell pertussis vaccines (WCPV) as part of the DPT vaccine, and since the 1990s, with acellular pertussis vaccines (aPV) as part of the DTaP vaccine in many economically developed countries. The immune response that develops after whooping cough persists for up to 20 years, compared to 4 to 14 years after WCPV vaccination, and up to 6 years after APV vaccination.

Aim. Assessment of the safety of the live recombinant pertussis vaccine «GamLPV» in a multicenter, blind, randomized, placebo-controlled study with double intranasal administration to adult volunteers.

Materials and methods. The study involved 260 adult volunteers aged 18 to 65 years: 210 people in the study «GamLPV» group and 50 people in the «Placebo» group. The vaccine «GamLPV» was administered in a dose of 4.5 x 109 CFU intranasally twice with an interval in 60 ± 5 days, as well as the comparison drug (Placebo). Safety and tolerability were assessed based on data on the frequency of registration, nature and severity of adverse events (AEs) with a double intranasal drug administration of the vaccine.

Results and discussion. During the study, no serious and severe AEs were registered. The analysis of the registered AEs did not confirm a reliable dependence on the administration of the GamLPV and, when compared with placebo, did not reveal statistically significant differences. We show that there was no statistically significant difference in safety parameters between the compared groups of volunteers who administered the GamLPV or placebo. The data from laboratory and instrumental examinations did not reveal significant deviations from the norm and the difference between the «GamLPV» and «Placebo» groups.

Conclusions The results of the phase III of clinical trial vaccine in adult volunteers indicate good tolerability and a high safety profile of the GamLPV vaccine. Based on the conducted research, permission was obtained from the Ministry of Health of the Russian Federation for a new clinical trial of the GamLPV with the participation of volunteers aged 6 and 14 years.

Relevance Aims. Development of an algorithm for calculating the epidemiological and economic effectiveness of Mass PCR testing for SARS-CoV-2 infection in the Russian Federation during 2020–2022.

Materials and methods. Rospotrebnadzor Statistical form №1035 «Monitoring the number of cases of coronavirus infection, including community-acquired pneumonia, and deaths» for 2020- 2022. Circulating variants SARS-CoV-2 is obtained from VGARus. PCR-testing results for SARS-CoV-2 infection were obtained from the Russian information system «SOLAR», demographic data - from Rosstat (Federal State Statistics Service). The base reproductive number (R0) used in the study was: Wuhan + Alpha – 2.74, Delta – 5.02, Omicron SARS-CoV-2 – 9.5. The average cost of one completed case of a new coronavirus infection (COVID-19) in hospitalization or outpatient treatment for the Russian Federation: asymptomatic and mild in the outpatient option – 28,000 rubles, moderate illness – 122,000 rubles. Severe, critical and moderate illness – 216,000 rubles. Statistical analysis was performed using standard methods of variation statistics. SciPy, Pandas, Statsmodels were used for statistical processing of the results obtained and data visualization.

Results. During the period 2020–2022, mass PCR testing for SARS-CoV-2 infections in Russian Federation has prevented an estimated between 4.83 million to 1.58 billion COVID-19 cases. The total damage averted from COVID-19 for 2020 to 2022 through mass PCR-testing of the population in the Russian Federation and subsequent isolation, amounted to 3,013 to 10,323 billion rubles.

Conclusion. Mass PCR-testing for SARS-CoV-2 infection is highly cost-effective and has reduced the averted damage from COVID-19 by 1.8–3.8 times in 2020-2022.

Relevance. Rotavirus infection remains of high epidemiological importance in the pediatric population of the Russian Federation, characterized by the predominance of moderate forms and a significant proportion of hospitalizations, which determines the need for a detailed study of its clinical and epidemiological characteristics at the regional level.

Aim. To study the clinical and epidemiological features of the course of rotavirus infection in hospitalized children aged 0–17 in the Altai Krai in the period 2015 - 2023.

Materials and methods. A retrospective analysis of official statistical reporting data (Form No. 2) and medical documentation (Form 003/u) of 3039 hospitalized children was carried out. The data was processed using the calculation of intensive and extensive indicators, the calculation of the arithmetic mean (X) and the standard error of the mean (m). The exact confidence values (95 %) for the proportions in the STATISTICA-10 program were calculated. Correlation analysis with calculation of the Pearson correlation coefficient (r) was used to assess the relationship between the severity of rotavirus infection and the frequency of clinical symptoms. The critical significance level was assumed 0.05 in all statistical analysis procedures.

Results. In the group of children aged 0-17, there was a 2.5-fold decrease in the incidence of rotavirus infection (from 337.4 to 137.4 per 100,000 child population, p = 0.0233). The proportion of hospitalized children was 10.0 % in 2017 and 75.3 % in 2023 (an average of 41.8 %). On average, children 1–2 years old were more often admitted to the hospital – 39.0 %; 3–6 years old – 29.5 %; children under 1 year old – 17.0 %; 7–14 years old – 13.0 %; 15–17 years old – 1.5 % The majority of hospitalized children were disorganized (53.3 %). The majority of children, 236 (62.9 %), were infected in the family. The analysis of the severity of rotavirus infection revealed a predominance of moderate severity – 94.7%. A strong positive correlation was established between the severity of rotavirus and the main clinical manifestations of the disease: the intensity of vomiting (r = 0.96), diarrhea (r = 0.87) and fever (r = 0.98). On average, patients with mild severity spent 4 days in the hospital, those with moderate severity spent 5 days, and those with severe severity spent 6 days. Concomitant pathology was detected in 12.4 % of hospitalized children, and life–threatening complications (convulsive syndrome, systemic inflammatory response syndrome (SIRS) with organ failure) – in 0.16 %. Complete clinical recovery upon discharge was recorded in only 58.4 % of children.

Conclusion: Thus, a significant burden of rotavirus infection remains in the Altai Krai, requiring hospitalization, especially among young children. There are clear correlations between the severity of infection and the main clinical manifestations. The high frequency of incomplete treatment justifies the need to optimize therapeutic and preventive measures, among which vaccination can play a key role.

Relevance. The problem of resistance to antibacterial drugs is one of the main ones for the healthcare systems of the Russian Federation and other countries. Currently, there is an increase in the number of antibiotic-resistant strains both among pathogens of infections associated with the provision of medical care and among representatives of the normal microbiocenosis of non-sterile loci of the human body.

The purpose of the study is to analyze changes in the structure of genetic determinants of antibiotic resistance of ESBL-producing representatives of the order Enterobacterales isolated from patients of the perinatal center during six years monitoring.

Materials and methods. The genetic profile of antibiotic resistance was determined in ESBL-producing strains of Enterobacteria isolated from samples of biological material obtained from 221 women and 241 newborn children hospitalized in the departments of the Federal State Budgetary Institution "Research Institute of OMM" of the Ministry of Health of Russia in the period from 2019 to 2024. inclusive. DNA of bacterial cells was isolated from a daily culture of microorganisms using the PROBANK kit, detection of the tem, ctx-M-1, shv genes; oxa-40-like, oxa-48- like, oxa-23- like, oxa-51- like, imp, kps, ges, ndm, vim were carried out using the diagnostic kit «BakResist GLA» on the detecting amplifier DT-48 (DNA -technology, Russia ). To assess the statistical significance of differences in gene frequency of occurrence of genes, Pearson's x2 test with Yates' correction was used.

Results and discussion. The number of genovariants of antibiotic resistance of Enterobacteriaceae isolated from patients in obstetrics and gynecology departments from 2019 to 2024, as well as in children, increased from 3 to 7. However, the dynamics of increasing diversity of genetic determinants of antibiotic resistance differed. Thus, in 2019, 3 genovariants were detected, in 2020, 4 variants were recorded, and in the next year, 2021, 6 genovariants were registered. In the next three years (2022 – 2024), the spectrum of determinants of antibiotic resistance was represented by 7 genetic variants, their structure underwent changes. In 2019, the blaCTX-M and blaSHV genes predominated with the same frequency (30 %). In 2020, the blaCTX-M + blaTEM genovariant was isolated more often (37.5 %). In 2021, 2022 and 2024 strains with the blaCTX-M gene dominated, registered in 59.5 %, 37.7 %, 36.9 % of cases, respectively. In 2023, the frequency of isolation of the blaCTX-M gene (27.1 %) was comparable to the frequency of occurrence of the blaCTX-M + blaTEM genovariant (30 %) (p = 0.852). The genetic profile of antibiotic resistance of Enterobacteriaceae strains isolated from patients in obstetrics, gynecology and pediatric departments is represented by 12 genovariants, in which the dominant gene providing resistance to beta-lactam antibiotics among Enterobacteriaceae during the entire observation period is blaCTX-M. The absence of significant differences in the frequency of occurrence of the studied antibiotic resistance genes and their combinations in Escherichia coli and Klebsiella pneumoniae strains isolated from both children and women indicates the same genetic determinants that ensure the synthesis of enzymes that inactivate beta-lactam antibacterial drugs of the cephalosporin group. The dynamics of changes in the structure of antibiotic resistance genovariants and the predominance of one or another type of bacteria may differ in departments of different profiles, which requires continuous monitoring of the spectrum of species diversity of bacteria and their antibiotic sensitivity for timely recording of the deterioration of the epidemiological situation and the adoption of adequate anti-epidemic measures.

Relevance. The Republic of Uzbekistan is implementing a national programme to prevent the spread of HIV and expand treatment coverage for HIV-infected residents, HIV resistance testing is being introduced into clinical practice for the first time at the Republican AIDS Centre.

The aim of the study is to investigate the prevalence of HIV-1 mutations associated with viral resistance to antiretroviral drugs among residents who have failed therapy.

Materials and methods. HIV-1 resistance development was performed for 194 patients with registered virological treatment failure. The nucleotide sequences of the pol gene encoding HIV-1 protease and reverse transcriptase were obtained by sequencing amplified fragments of the virus. Mutational analysis was performed using specialized software.

Results and discussion. In 42.3% of cases HIV-1 did not have any resistance mutations, which indicates low patient adherence to treatment or covert rejection of therapy. HIV-1 resistance mutations were detected in 112 of the 194 samples (57.7%); mutations to two classes of drugs were found in 59.8% of cases, in 3.6% to three classes. Of the 112 patients 66 had HIV RNA concentrations in their blood exceeding 50,000 copies/ml, and the viruses isolated from them had medium and high levels of resistance to ART drugs, which creates the conditions for the transmission of resistant viruses.

Conclusion. The introduction of HIV resistance testing into clinical practice is a key measure in the comprehensive program to combat the epidemic, aimed at resolving the problem of the emergence and spread of drug-resistant strains of HIV-1 in the country.

The relevance of the problem is due to the complex epidemiological situation with brucellosis in the Russian Federation. Since 2023, foci of animal brucellosis with cases of human disease have been registered in the previously brucellosis-free territory of the Republic of Tatarstan (RT). Objective. Analysis of brucellosis outbreaks that occurred in the RT in 2023–2024.

Materials and methods. The article presents the results of the epizootic and epidemiological investigation of brucellosis foci. The data from form 2 of the federal statistical observation “Information on infectious and parasitic diseases” in the Republic of Tatarstan for 2023 and 2024 and the data from the epizootological and epidemiological survey cards of the zoonotic disease outbreak were used.

Results. Since August 2023, a number of peasant farms (PF) and private households have begun to register repeated cases of abortions and stillbirths in cows; Brucella abortus was isolated from the biological material of the animals. During 2023–2024, 32 cases of occupational infection with brucellosis of people were recorded, which occurred as a result of direct contact of people with sick animals or contact with objects of the complex, tools, veterinary instruments contaminated with brucellae. The infection was facilitated by gross violations in terms of labor protection of workers, including failure to comply with working conditions and personal protective measures. The share of animals affected by brucellosis in large farms amounted to 19.6–21.2 % of the number of those examined in the foci, people – 12–36 % of the established number of contacts. Supervisory measures were initiated, including strengthening veterinary and sanitary control, conducting preventive visits of specialists to peasant farms that fall into the category of extremely high and high risk, conducting preventive examinations with serological testing for brucellosis of workers of all peasant farms in the republic, development and approval by the Government of the Republic of the Comprehensive Action Plan for the Prevention of Brucellosis for 2024–2028.

Conclusion. During 2023–2024, a deterioration in the epidemiological situation for brucellosis was noted in the Republic of Tatarstan. Infection of animals and people was facilitated by violations of sanitary and veterinary standards, sanitary and hygienic rules and safety precautions in the workplace. For the timely detection of occupational diseases, it is important to conduct regular medical examinations with serological testing of persons whose professional activities involve working with animals. Three-fold examination of contacts in foci significantly increases the effectiveness of diagnostic measures.

Relevance. The study of virus inactivation mechanisms remains a priority in the development of inactivated whole-virion vaccines. Criteria for selecting a suitable inactivator include complete elimination of viral infectivity and preservation of a high level of immunogenicity in the final product.

Aim. This work examines the action mechanisms of both classical inactivators (formalin, betapropiolactone) and UV irradiation. Besides, the article describes the latest promising inactivation approaches by hydrogen peroxide, gamma irradiation and psoralen.

Conclusion. The inactivator optimal choice depends on many factors: the nature of the virus, the required level of safety, manufacturing technology, and the final vaccine properties. The formalin and beta-propiolactone continue to dominate in the licensed vaccines production. Experimental vaccine preparations inactivated with hydrogen peroxide or by physical methods have shown a high level of immunogenic activity in various laboratory animal models. Despite the positive results, a new inactivating agent introduction requires significant effort and long-term testing to confirm its effectiveness and safety.

Relevance. Viral pandemics pose a global threat to public health and economics, placing an enormous burden on health systems in many countries. Historical examples such as the Antonine plague, the Spanish flu, and the SARS-CoV-2 pandemic, demonstrate their devastating impact on demographics and social stability. Modern factors, including urbanization, intensive population migration, close contacts with animals, and a high rate of RNA virus variability, increase the likelihood of new pandemics. Analyzing the history, causes, and consequences of pandemics, as well as developing control strategies, remain priorities for epidemiology, virology, and vaccine prevention.

Aim. To analyze accumulated data in the field of epidemiological and virological research on geography, phylogenetics, and geoepidemiology of RNA viruses that have caused the largest outbreaks of diseases over the past century; and to evaluate modern strategies for preventing and managing pandemics with a focus on epidemiological surveillance.

Material and methods. The authors have reviewed scientific literature, including historical sources, epidemiological data, and findings of molecular genetic research. The analysis of pandemics caused by influenza A (H1N1, H2N2, H3N2) viruses, coronaviruses (SARSCoV-1, MERS-CoV, SARS-CoV-2) and filoviruses (Ebola, Marburg) has been undertaken. The mechanisms of reassortment and mutation of RNA viruses, as well as the influence of anthropogenic and biotic factors on their spread have been studied. WHO data, Russian and international studies, including the domestic VGARus platform for aggregating data on the genomes of circulating SARS-CoV-2 viruses, have been explored.

Results and discussion. Influenza A viruses and coronaviruses have a high pandemic potential due to their variability, zoonotic origin, and ability to airborne transmission. Pandemics of the XX–XXI centuries, including the “Spanish flu” (1918-1919) and SARS-CoV2 (2019-2025), have demonstrated a significant impact on demographics, economics and medicine development. Filoviruses cause local outbreaks with high mortality, yet their epidemic potential is limited due to the lack of an airborne transmission mechanism and an endemic nature of their existence. Modern genomic surveillance technologies such as GISRS and VGARus, make it possible to monitor the development of viruses, allowing for regular updating of vaccine strains. The COVID-19 pandemic has highlighted the importance of digitalization, telemedicine, and operational regulatory measures with the use of available resources. However, the asymptomatic course and rapid evolution of viruses make it difficult to control the situation with outbreaks.

Conclusion. Viral pandemics remain an unavoidable threat, requiring a comprehensive approach to their prevention and control. Advances in vaccine prevention, genomic surveillance, and health digitalization demonstrate a potential to minimize the effects of future pandemics. International cooperation, timely regulatory measures, and further development of the national biosafety systems for rapid response to new pathogens are critically important.

Relevance. Rubella remains a significant public health concern despite substantial progress in its elimination in many countries worldwide. Disruptions to routine immunization programs during the COVID-19 pandemic, uneven vaccination coverage in certain regions, and the presence of population groups create conditions for the continued risk of importation, localized outbreaks, and the occurrence of congenital rubella syndrome.

Aim. To analyze the current epidemiological situation of rubella worldwide and in the Russian Federation, assess trends in incidence and vaccination coverage, and review key approaches to vaccination strategies and maintenance of elimination status.

Conclusion. The analysis demonstrates persistent heterogeneity in the epidemiological situation of rubella across different regions of the world despite an overall decline in incidence. Even in countries that have achieved elimination, the risk of renewed transmission persists in the presence of unvaccinated cohorts and population groups at increased risk. Maintaining elimination status requires high vaccination coverage, effective epidemiological surveillance, and the implementation of catch-up immunization campaigns, with particular emphasis on the prevention of congenital rubella syndrome.