Relevance. Hemorrhagic fever with renal syndrome (HFRS) and tick-borne encephalitis (TBE) are the most common natural focal diseases of viral etiology In Russia. The medical and social significance of these two infections is determined by the extensive fociof their spread, high annual morbidity rates in the population, and the possibility of developing severe forms of the disease leading to permanent disability and death. The causative agents of HFRS In Russia are 6 types of hantaviruses Hantaan, Amur, Seoul, Puumala, Kurkino and Sochi, which, immunologically and genetically significantly different from each other, support their existence in nature through six different species of small mammals, which are sources of infection in humans. TBE virus strains that cause disease in humans belong to five phylogenetically distinct subtypes, including: Far Eastern, European, Siberian, “178-79” and Baikal. Aim. Analysis of the role of small mammals and ticks in the ecology of HFRS and TBE pathogens. Conclusions. Small mammals retain and transmit hantaviruses to uninfected animals and ticks. At the same time, ticks retain and transmit to ticks and mammals not only the TBE virus, but also hantaviruses. Despite the taxonomic difference between the viruses that cause HFRS and TBE, some of their ecological properties are similar.

Relevance. The high infectivity and mutagenicity of SARS-CoV-2, combined with the relative short duration of the immune response, means that the problem of controlling the incidence of COVID-19 will continue to be relevant. Aims. To plan anti-epidemic measures, you need to know the quantitative value of the basic reproductive number (R0), however, the available methods for estimating the R0 made it possible to estimate it only for the initial version of SARS-CoV-2. In this regard, the task was set to develop a method for estimating R0 for current pathogen variants based on the rate of change from one variant to another, including both viruses and bacteria. Materials and methods. A modification of the SIR model for two variants of SARS-CoV-2 and actual data on the incidence of COVID-19 and the results of sequencing the virus SARS-CoV-2 isolated in Moscow are used. Results. It was found that for the SARS-CoV-2 Delta variant R0 was about 10, and for the current Omicron variants it exceeds 30. Discussion. In contrast to existing methods, the proposed method allows one to estimate R0 in the context of anti-epidemic measures, as well as by the dynamics of morbidity in a population with a collective immune status, taking into account the typical structure of the circulating SARS-CoV-2. Conclusion. The proposed method makes it possible to estimate the change in the basic reproductive number of the SARS-CoV-2 based on the rate of displacement of one variant by another

Relevance. To control COVID-19, a net of special infection hospitals and departments was created, a system of medicaments and protective means’ supply was set up, necessary normative and regulatory documentation was developed and overall vaccination of population was performed in Moscow. Within frames of work for prophylaxis of COVID-19 spread in patients with tuberculosis at in-patient units of the State Budgetary Healthcare Institution of Moscow city «The Moscow Research and Clinical Center for Tuberculosis Control of the Moscow Government Department of Health” (hereinafter referred as the Center), observational departments for treatment of patients with tuberculosis from COVID-19 contact and convalescents after COVID-19. Aims. To evaluate specialized observational departments’ work as part of general anti-epidemic control measure system for COVID- 19 at tuberculosis hospitals. Materials and methods. The observational departments’ work within the period of 2020–2022 with 1075 patients treated including 400 patients from COVID-19 contact areas (37.2%) and 675 convalescent patients after COVID-19 (62.8%), was analyzed. The results obtained during the study were statistically treated by means of application program package Microsoft Office 2007. The quantitative parameters with presumably normal distribution were described with mean arithmetic values (M) and standard deviations (SD), and 95% confidence interval (CI 95%). The estimation of significance of differences between outcomes was evaluated with the Pearson χ2 test. The differences were considered to be statistically significant with p < 0,05. Results and discussion. The evaluation data on functioning efficacy of observational departments for patients with tuberculosis from COVID-19 contact and convalescent patients with tuberculosis after COVID-19 within the large medical institution hospital of physiatry profile. Among all patients, 153 of patients who fell ill with COVID-19 (14.2%; 95% CI [12.21–16.38%]) were determined, which lowered the number of COVID-19 areas at in-patient departments of the Center by 11.8%. The mean timeframes of COVID- 19 determination in general were 8.0 days: 5.4 days among contacts from new coronavirus infection areas and 12.4 days among convalescents at the department for the treatment of patients with tuberculosis and new coronavirus infection. The comparative analysis showed that COVID-19 was more frequently determined in tuberculosis patients from the contact with those who fell ill with COVID-19 (p < 0.001) than in convalescents. Conclusions. During medical care for patients of physiatry profile in Moscow city, a wide range of management decisions consisting in the change of routing system in specialized medical care, was taken. Among them, creation and functioning of observational departments for contact persons from COVID-19 areas and convalescents after COVID-19 play a particular role.
Creation of such departments within a large medical institution enabled the contemporary isolation of contact persons from COVID- 19 areas and convalescents after COVID-19 and allowed the additional control of nosocomial infection spread

Relevance. Hemorrhagic fever with renal syndrome (HFRS) is leading among natural focal human diseases in Russia, the causative agents of which - orthohantaviruses - belong to the order Bunyavirales, family Hantaviridae. More than 98% of HFRS cases in Russia are caused by the Puumala virus. It is a serious zoonosis for which there is still no specific treatment. The WHO has not approved a vaccine. The aim of this study was to investigate the effect of formaldehyde, β-propiolactone, hydrogen peroxide, ultraviolet rays, gamma irradiation and thermal inactivation on the immunogenic activity of inactivated vaccine preparations against HFRS Materials and methods. To achieve this aim, experimental vaccine preparations based on the PUU-TKD/VERO strain of Puumala virus were prepared and inactivated using the methods described above. The time intervals required for complete inactivation of the virus were determined, and the effects of the inactivators on viral RNA and immunogenic activity of the vaccine preparations were evaluated in BALB/c mouse and Syrian hamster models. Results. According to our results, vaccine preparations inactivated by different chemical and physical methods, which differ significantly in the mechanism of the mechanism of interaction with the virus, show no significant differences in immunogenic activity, except for thermal inactivation. Conclusion. A certain advantage of β-propiolactone is the short virus inactivation time, its complete degradation into non-toxic compounds within a few hours, and the reduction of total protein content after sterilization filtration, which is probably due to less aggregation of virus particles and cellular proteins

Relevance. Effective responses are required due to the high incidence of cervical cancer (Cc) throughout the World. RT-PCRbased HPV-testing is becoming more prominent in secondary prevention worldwide, replacing cytology. Russian practice still relies on cytology as the primary method mainly because there is a lack of comparative evaluation of the diagnostic characteristics of cytology and HPV-tests. Aim. Evaluation of diagnostic characteristics of laboratory methods and the relevance of extended HPV genotyping for secondary prevention of cervical cancer. Materials & methods. The study included data (liquid cytology, histology, HPV-test results) from a survey of 653 women (M = 33.55 years old, ME = 32.0 years old, IQR: 26-38 years old) infected with 14 HPV types (16, 18, 31, 33, 35, 39, 45, 45, 51, 52, 56, 58, 59, 66, 68), with presence or absence of intraepithelial neoplasia of varying severity. The study analyzed the correlation of cervical cytology - histology, clinical sensitivity for high-grade squamous intraepithelial lesions (HSIL+), the incidence and the role of 14 oncogenic HPV types in the development of cervical intraepithelial pathology, positive predictive value (PPV) and the diagnostic accuracy of the HPV-test. Results. The agreement between cytology and histology is 67.20%. Clinical sensitivity of cytology is 83.78% for HSIL+ and 94.34% for any other than NILM result. The structure of the HPV population varies depending on the degree of neoplasia, with a constant predominance of HPV16. The clinical sensitivity of the laboratory component rises to 99.5% by conducting HPV-test for at least 12 types of virus. HSIL is more commonly associated with viruses of alpha-9 phylogenetic group, than with alpha-7 and alpha-5/6. The positive predictive value for HSIL+ is reduced depending on the HPV type: 16>33>58>35>45>31>18>52>39>59>58>56>68>66. Conclusions. Clinical sensitivity of the HPV-test exceeds that of cytology, so that secondary prevention of cervical cancer can be effectively achieved through HPV testing. The introduction of an extended genotyping provides more complete information about the risk of having HSIL+. The data obtained will form the basis for the development of directions for improving the epidemiological surveillance information subsystem of HPVassociated cervical diseases

Relevance. Non-polio enteroviruses are widespread worldwide, with millions of cases being reported each year, but limited data exist on the true burden of enterovirus (non-polio) infections (EVnI) worldwide due to a lack of standardized surveillance. Considering the absence of specific prevention of EnVI and the difficulty of predicting the epidemic situation due to the diversity of types of enteroviruses, there is an obvious need for substantiating and supplementing the existing parameters of epidemiological monitoring, identifying additional indicators of morbidity risk for the purpose of timely implementing preventive and anti-epidemic measures. Aim. Rationale of necessity of additional measures of the EVnI observation for early discovery of the activation of the epidemic process. Materials and methods. The research was held during the year 2023 and included the following three components: 1. The prospective continuous observation of the patients ranging from 0 to 18 years old who received medical help in ambulatory conditions. Possible symptoms of EVnI were studied using the ambulatory diseased person’s medical cards (f. № 0/25у). 2. The research of biological material, which belonged to the healthy people and people with signs of probable EVnI. 3. The study of epidemiological connection of dew point temperature with the manifestations of the EVnI epidemic process. Results. Probable clinical symptoms of EVnI are found among 511 observed children. Positive correlational connection with EVnI is visible among exanthems (0,43, p < 0,001) and acute nasopharyngitis (0,13, p < 0,001). The maximal incidence rate of EVnI is discovered in a period from 27th to 36th week (54,35 ‰), which coincides with maximal incidence rate of acute nasopharyngitis (434,78 ‰). The rise in incidence rate of EVnI in comparison to the last period is 4,45 times (p < 0,001), while in comparison to the rise in incidence rate of acute nasopharyngitis is 2,71 times (p < 0,0001). In planned observation of examined patients with probable symptoms, EVnI disease is found amongst 78 people, the incidence rate made 254,07 ‰ and that aligns with the results of active observation of health center appeals (267,68 ‰, p > 0,99). Clinical diagnosis of EVnI is made only in 51,28 %% of all cases. As a result of ill and healthy people’s observation, their relation is found to be 6:1 respectively. The activation of the epidemic process started in concurrence with dew point temperature +4,85 °C and continued until the dew point temperature +20,33 °C. Conclusion. The existing system of epidemiological supervision over EVnI has to be enhanced by adding the research on NPEV among the people who have acute nasopharyngitis during the stable rise in dew point temperature from +5,0 °C. Taking into account the rise in the incidence rate of EVnI, it is reasonable to expand the microbiological observation of biological material which belongs to the people who have exanthems, diarrheal syndrome and healthy people

Relevance. Leptospirosis is a zoonotic ubiquitous natural focal infectious disease that has an adverse effect on human and pet health. The territory of the Republic of Belarus in terms of its natural-climatic and soil-geographical conditions is favorable for the existence of both natural and anthropurgical foci of leptospirosis. The purpose of the work is to study the long-term dynamics of the incidence of leptospirosis in the population of the Gomel region and the clinical and epidemiological features of leptospirosis. Materials and methods. The material for the study was the data of the state statistical reporting «Report on individual infectious, parasitic diseases and their carriers» for the period from 2002 to 2022. In this work, epidemiological diagnostic methods and statistical research methods were used. Descriptive retrospective continuous study of these case histories of patients diagnosed with Leptospirosis of the Gomel Regional Infectious Diseases Clinical Hospital institution was conducted to describe clinical data. Results. In the period from 2002 to 2022, 161 cases of leptospirosis were registered in the Gomel region with an average incidence rate of 0.52 per 100 thousand population. Over this period of time, the incidence of leptospirosis was characterized by an uneven distribution and was undulating. Periods with a low incidence of 0.14–0.42 cases per 100 thousand population lasting 5-6 years alternated with periods of rising incidence to 0.99 cases per 100 thousand population lasting 3 years. In 2022, a sharp rise in the incidence of leptospirosis in the Gomel region was registered, and therefore 15.8 times higher than the incidence in 2021, the incidence rate was 1.11 per 100 thousand of the population and exceeded the national average by 4.6 times. Adults predominated among the sick (93.3%). At the same time, 73.0% of the patients were urban residents. The source of infection in 81.2% of cases were rodents, in 7.52% of cases domestic animals. In 7.52% of cases, the disease appeared as a result of professional activity, only in 3.76% of cases the disease occurred after swimming in open water. Thus, the main route of transmission of leptospirosis at present is contact (88.72%), alimentary and water are less important, respectively 7.52% and 3.76%. Results of serological examination for leptospirosis by RMA showed that 5 serogroups of leptospir circulate among rodents: L. Pomona and L. Canicola, L. Grippotyphosa, L. Icterohaemorrhagiae, L. A. Ustralis. 36.4% of the samples showed a positive result at the same time to several serogroups. L. Grippotyphosa, L. Cterohaemorrhagiae and L. Pomona were detected more often, in total, these pathogens accounted for 46.5% of positive samples. The results of the survey of farm animals showed that 60.6% of the sera studied had positive results of RMA with leptospirs of several serogroups. L. Sejroe was also isolated – in 12.3% of samples, L. Hebdomad – in 1.3% of samples, L. Icterohaemorrhagiae – in 1.2%, L. Pomona – in 0.3%, others – 24.2%. In the period from 2002 to 2021, the following serogroups were isolated in patients with leptospirosis: L. Grippotyphosa – 36%, L. Pomona and L. Canicola – 16%, L. Australi – 13%, L. Wolffi – 9%, L. Icterohaemorrhagiae – 7% and L. Tarassovi – 3%. In 2022, there is a change in the polytypage of leptospir: L. Icterohaemorrhagiae (6.7%), L. Tarassovi (6.7%), L. Wolffi (6.7%), L. Pomona (13.3), L. Astralis (13.3), L. Canicola (6.7%), 6.7% – L. Sejroe, L. Grippotyphosa Moskva – 40%. For the period from 2005 to 2022, 49 people diagnosed with leptospirosis were treated at the Gomel Regional Infectious Diseases Hospital, of which men accounted for 69%, the average age of patients was 34.5 ± 3.8 years. Most patients are hospitalized on day 6 [4 – 8] of illness. All patients complained of fever, 86% of patients had muscle pain, headaches were recorded in 56.0%, yellowing of the skin and sclera – 34.0%, abdominal pain – 38%, 25% of patients reported nausea, vomiting, diarrhea syndrome. 28.6% of patients had an icteric form of leptospirosis, Weil's syndrome was diagnosed in 9.3% of patients, hemorrhagic syndrome was observed in 18.7% of patients. All patients had laboratory confirmation of the diagnosis. The duration of hospitalization was 15 [9 – 23] days. 1 case of the disease ended with a detailed outcome for the entire observation period. Conclusion. The incidence of leptospirosis in the Gomel region is undulating and is characterized by a change in periods of rising incidence lasting up to 3 years with periods of low incidence lasting up to 5 years. The results of the study suggest that the emergence and spread of the leptospira serotype in the territory led to a new increase in the incidence. Thus, continuous qualitative monitoring of leptospira serotypes among the population of sources of infection should be carried out.

Relevance. Obesity is associated with the risk of developing insulin resistance and type 2 diabetes mellitus (type 2 DM). Over the past 40 years, no country in the world has seen a decrease in the incidence of either obesity or diabetes. The epidemic growth rates of type 2 DM in the world, including in the Russian Federation, emphasize the close relationship of these endocrinopathies and identify obesity as one of the determinants of diabetes development. Aim. To study the intensity, dynamics and features of the formation of primary morbidity of obesity and type 2 DM among various population groups, as well as to identify correlations between the studied parameters in the groups. Materials and methods. A retrospective analysis of the primary incidence of obesity and type 2 DM in Russia in 2010–2021 was carried out. The source of the analyzed information was the statistical collections of the Ministry of Health of the Russian Federation «Morbidity of the population». To identify the relationship between the studied parameters, a correlation analysis was performed with the calculation of the Pearson coefficient (r). The interpretation of the closeness of the correlation was performed on the Chaddock scale. Results. The number of cases of obesity amounted to 4 428 975, type 2 DM – 3 839 772 in Russia in 2010–2021. The incidence of obesity among the entire population was 253,61 per 100 ths, type 2 DM – 220,47 per 100 ths population. The Siberian FD (377,29 per 100 ths) should be singled out as an epidemiologically significant obesity district, and for type 2 DM – the Southern FD (249,34 per 100 ths). The incidence of type 2 DM among adults was 274,22 per 100 ths, while the leading positions were taken by the Ural FD (313,56 per 100 ths) and the Southern FD (308,94 per 100 ths). In terms of obesity among adults, it should be noted that the Siberian FD is 359,21 per 100 ths (the excess of the incidence rate in Russia is 1,68 times). Among the elderly, the incidence of obesity in Russia was 1,15 times higher than in adults (247,15 per 100 ths), while in the Siberian FD the incidence was 1,23 times higher than in adults (440,9 per 100 ths). In the elderly population group, the maximum incidence of type 2 DM was noted in the Ural FD – 591,11 per 100 ths. The incidence of obesity among the children from 0 to 14 years was 370,99 per 100 ths, while the most unfavorable epidemic situation was noted in the North-Western FD (476,86 per 100 ths – exceeding the level in Russia by 1,29 times). Among the children from 15 to 17, the incidence of obesity was 697,67 per 100 ths, the maximum level was in the North-Western FD (869,1 per 100 ths) and the Southern FD (866,43 per 100 ths). In parallel, the North-Western FD is also leading in terms of type 2 DM (3,16 per 100 ths) among the teenagers 15–17 years old. Positive correlations between obesity and type 2 DM were established among the entire population of Russia in 2020 (r = 0,364 – weak level) and in 2021 (r = 0,260 – very weak level). Conclusion. A close association of obesity with the development of type 2 DM has been confirmed. In Russia, in parallel with the growth of obesity, there is an increase in type 2 DM. Special attention should be paid to the child population, since there is a pronounced trend towards an increase in the incidence of obesity among the children 0–14 years old and 15–17 years old. The level of type 2 DM is also increasing among the teenagers. A statistically significant correlation was obtained between obesity and type 2 DM among the entire population.

Relevance. The urgency of the problem of rotavirus infection, primarily among children, is due to the steady preservation of leading places in the structure of childhood morbidity. Despite the existing preventive measures, the incidence of rotavirus infection has been steadily increasing over the past 10 years. Vaccination coverage in our country in recent years has not exceeded 10-12% of the target cohort, which in general cannot have a significant impact on the incidence of rotavirus infection and requires special attention. Aim. To assess the epidemiologic situation on the incidence of rotavirus infection in Altai Krai in 2001–2023. Materials and methods. A retrospective epidemiological analysis of the incidence of rotavirus infection in the Altai Krai was carried out using data from statistical reporting forms No. 2 of the Federal State Statistical Observation «Information on infectious and parasitic diseases» in the Altai Krai in 2001–2023. Results. A long-term retrospective epidemiological analysis of rotavirus infection incidence was carried out. It was noted: an increase in the share of rotavirus infection in the structure of acute intestinal infections; a tendency for an increase in morbidity rates in the Altai Krai; the average long-term morbidity rate among children 0–17 years old exceeded that among adults by 67 times; in the structure of cases, the main proportion was children 1–2 years old; the greatest contribution to the formation of morbidity was made by unorganized children (75%) vaccination had no effect on morbidity, since vaccine coverage of Altay Krai population does not exceed 0.1%. Conclusion. The reasons for close monitoring of rotavirus infection and improvement of preventive measures, including vaccine prophylaxis, are substantiated

Relevance. K. pneumoniae is a common nosocomial pathogen in pediatric hospitals, often characterized by the presence of a wide range of virulence factors and genetic determinants of antibiotic resistance. Аim. To analyze the results obtained during wholegenome sequencing of a Klebsiella pneumoniae strain isolated from a positive blood culture of a premature newborn. Materials and methods. An ESBL-producing strain of K. pneumoniae isolated from a positive blood culture of a newborn premature infant. Sequencing was performed on the MiSeq platform (Illumina). Analysis of DNA nucleotide sequences of the complete genome of K. pneumoniae was carried out using the website of the Center for Genomic Epidemiology. The search for genetic determinants of antibiotic resistance and virulence was carried out using online services. Results and its discussion. The resulting nucleotide sequence was 5,414,099 bp in length, and the proportion of GC nitrogenous bases was 57.3%. The isolated strain belonged to the sequence type ST3559, had 4 genes encoding the synthesis of enzymes that hydrolyze antibacterial drugs from the beta-lactam group, 2 genes providing resistance to quinolones/fluoroquinolones, 1 resistance gene each to trimethoprim, chloramphenicol, fosfomycin and aminoglycoside antibiotics. Most of the virulence factor genes identified in the studied strain ensure the recognition and absorption of iron ions necessary for the competitive functioning of the bacterial cell. K. pneumoniae possesses the acrA efflux pump gene and its regulators, as well as 4 prophage particles and 1 CRISPCas IE system. Conclusions. Whole-genome sequencing of the K. pneumoniae strain isolated from a positive blood culture of a premature newborn allows us to characterize in detail the causative agent of a generalized infection and detect a wide range of genetic determinants of virulence factors and antibiotic resistance. The ESBL-producing strain of K. pneumoniae, as the etiological agent of neonatal sepsis, was characterized by the presence of virulence genes, multidrug resistance, both due to genes encoding enzymes that hydrolyze antibiotics, and due to the presence of efflux pumps and their regulators. The use of the results of traditional cultural research methods together with high-throughput sequencing data is a promising area of scientific research and has a reserve of practical application in the field of clinical medicine, genetics of microorganisms, molecular epidemiology at the local and global levels

Relevance. In epidemiological surveillance of West Nile fever (WNF), infection of West Nile virus (WNV) in zoological and entomological material is an important indicator of the activity of the natural focus, which can be used to predict the development of the epidemiological situation, adjust the scope and timing of prophylactic and anti-epidemic measures. It is noteworthy that there were no positive findings or single detections of WNV markers in zoological and entomological material in most subjects of the European part of the Russia. Aims. To obtain estimated data on the intensity of the epizootic process of WNF in the territory of the European part of Russia. Materials and methods. Collection of zoological and entomological material of WNV in 2021-2023 was conducted in the territories of 32 entities of the Russian Federation in accordance with the current regulatory and methodological documents. Field material was analyzed by RT-PCR using the AmpliSense WNV-FL test system, and genotyping of samples positive for WNV RNA was performed using the Ampligen-WNV-genotype-1/2/4 test system. Results and Discussion. During the period 2021–2023, in the course of this study vertebrates were captured: 774 birds, 1126 small mammals, and 22 frogs; and arthropods were collected: 142600 bloodsucking mosquitoes, 33 bloodsuckers, 3070 midges, 14049 ixodid ticks, and 71 argas ticks. WNV RNA was detected in 9 out of 1922 studied vertebrate animals and in 112 out of 8047 pools of blood-sucking arthropods. The infection rate of blood-sucking mosquitoes was 0.07%, ixodid ticks – 0.09%, birds – 0.9%, frogs – 9.1%, which indicates that these animal groups are widely involved in the epizootic process. Markers of WNV in field material were detected in 14 entities. In 6 of them positive findings were obtained for the first time. WNV RNA of 1 genotype was detected in pools from the Central Federal District, 2 genotypes - in all surveyed districts, 4 genotypes - from the Southern Federal District. Conclusions. Active reconnaissance studies led to the expansion of our ideas about the existence of WNF foci in the European part of Russia. In populations of birds and blood-sucking arthropods in this area, WNV is steadily circulating. WNV-infected birds were found in the Southern Federal District and the Central Federal District, mosquitoes – in all surveyed federal districts, amphibians and ticks – only in the Southern Federal District

Aim. To analyze dynamic of incidence and mortality of COVID-19 and clinical and epidemiological characteristics of adult patients with a new coronavirus infection during the early period of the Omicron SARS-COV-2 distribution in Russia. Materials and Methods. We conducted a retrospective analysis of the dynamics of COVID-19 incidence and mortality in Russia until 2023. Study included patients aged ≥18 years with a laboratory-confirmed diagnosis of COVID-19, detected in the period from 01/02/2022 to 14/03/2022 (n = 3 582 688) in 85 regions of Russia. Participants were included regardless their COVID-19 vaccination history. Results. We identified 6 periods of rise and decline in the COVID-19 incidence until 2023 in Russia. The 5th (January–July 2022) and the 6th (August-November 2022) periods were associated with the spread of the Omicron SARS-CoV-2. The median age of patients in the early period of Omicron spreading was 49 (36–62) years, 62.7% were women. The largest proportion of patients were represented by the age groups 30–39 and 40–49 years (19.2% each), the lowest – 18–29 years (12.3%). Proportion of patients with mild disease was 90.0%, moderate – 8.5%, severe – 0.9%, extremely severe – 0.6%. Hospitalization rate, proportion of patients treated in the intensive care unit and rate of invasive mechanical ventilation were 7.6%, 9.5% and 6.7% respectively. The median period from the onset of symptoms to the diagnosis was 2 (1–3) days, median of duration of the disease was 8 (6-10) days and median duration of hospitalization was 10 (7–14) days. The median age of the deceased patients was 77 (69–84) years, of which 50.8% were women, 72.6% were persons ≥70 years old. One or more concomitant diseases were detected among 8.7% of patients who became ill and 75.8% of those who died. The probability of hospitalization, admission to the ICU, IMV and death in patients with one or more concomitant diseases were 24.5, 3.2, 3.5 and 35.8 times higher, respectively, compared with patients without concomitant diseases. Conclusion. In the early period of the spread of the Omicron variant in Russia, among adult patients with COVID-19, excluding their vaccine history, the frequency of severe and extremely severe forms of infection was 1.5%. The elderly age and the presence of concomitant diseases remained key risk factors for the development of adverse outcomes of the COVID-19

Relevance. Currently, adolescents are protected against 8 infections within the framework of the National Vaccination Schedule: tuberculosis, viral hepatitis B, diphtheria, tetanus, measles, rubella, mumps and influenza (annually). Post-vaccination immunity to whooping cough, acquired in the first years of life, begins to decline since 4–7 years. In recent decades, there has been an increase in the incidence, including among adolescents, of such pathogens as Neisseria meningitidis, Streptococcus pneumoniae, Bordetella pertussis, strains of the human papillomavirus (HPV) of high oncogenicity, the herpes zoster virus and etc., that affect the creation of the foundation of future health nation. Aim. To substantiate the vaccination strategy for adolescents as one of the most important factors for creating the demographic security of the nation. Results. The burden of infectious pathologies of meningococcal, pneumococcal etiology, pertussis, HPV and herpes Zoster, its impact on the development of the health of adolescents in Russia and the intended tactics for implementing vaccination of young people with the help of modern immunobiological drugs are shown. Conclusion. Vaccination of adolescents against infections such as meningococcal and pneumococcal infections, whooping cough, chicken pox, and HPV is a strategic task, since reducing the risk of contracting infectious diseases in this age group directly affects the preservation of the demographic potential of the nation