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The aim of the study was to assess the dynamics of seroprevalence to SARS-CoV-2 in various population groups during the initial period of herd immunity formation based on multivariate analysis using logit regression models.Materials and methods. The study involved 1561 individuals divided into three population cohorts: people living with HIV/AIDS (PLHA), healthy blood donors, medical workers. The presence of antibodies to SARS-CoV-2 was determined in blood serum through ELISA using commercial reagent kits. Multivariate analysis of the dynamics of seroprevalence to SARS-CoV-2 was carried out using logistic regression models.Results and discussion. It has been revealed that probability of detecting IgG antibodies to SARS-CoV-2 significantly increased among the donors and medical workers in the spring-autumn 2020 series (p=0.005 и p

The aim of the research was to study reproduction features of SARS-CoV-2 coronavirus strains of various genetic lines on Vero and Vero E6 cell culture.Materials and methods. The SARS-CoV-2 virus strains related to the variants of concern (VOC) circulating in the territory of the Russian Federation were used in the research. The strains of the SARS-CoV-2 virus were deposited in the State Collection of Pathogens of Viral Infections and Rickettsioses at the FBIS SSC VB “Vector” of the Rospotrebnadzor. The experiments were carried out on Vero and Vero E6 cell cultures. The dynamics of infectious virus accumulation was determined by titration of culture fluid samples 24, 48, 72, 96 hours after infection (MOI – from 1 to 0,00001 CPE50/cell). Plaque formation was studied on Vero E6 cell culture under 0.2 % agar coating. Image analysis and plaque size calculation were performed using GIMP (GNU Image Manipulation Program).Results and discussion. The study describes the dynamics of accumulation of infectious virus in the culture fluid depending upon multiplicity of infection for the strains of SARS-CoV-2 virus belonging to different genetic lines. Differences in the morphology of plaques on the monolayer of Vero E6 cell culture under agar coating are shown. SARS-CoV-2 virus strains related to Alfa and Delta VOC demonstrate maximum reproduction rate among the studied strains (infectious titer is higher than 7 lg TCID50/100µl). Omicron VOC forms small plaques under agar coating and at a low multiplicity of infection has a low reproduction rate. Thus, SARS-CoV-2 virus strains belonging to different genetic lines have significant differences in the rate of reproduction on Vero and Vero E6 cell culture.

The aim of the research was to assess the susceptibility of mice of different lines to newly emerging variants of SARS-CoV-2.Materials and methods. The SARS-CoV-2 virus strains belonging to variants of concern (VOC) circulating in the territory of the Russian Federation were used in the study. Experiments involved three inbred mouse lines (BALB/c, CBA and C57Bl/6z) and CD1 outbred mice taken from the nursery of the SSC VB “Vector” of the Rospotrebnadzor. The infectious titer of coronavirus in tissue samples obtained from the laboratory animals was determined on a Vero E6 cell culture. The (Ct) threshold value in RT-PCR was considered an additional parameter for monitoring the viral load in the samples. The severity of lung tissue damage was assessed using histological preparations.Results and discussion. The susceptibility of various mouse lines to the genetic variant Beta of the SARS-CoV-2 virus has been investigated. During intranasal infection of the inbred and outbred mice with strains of VOC at a dose of 2·103 TCID50, the virus replicated in the lungs with maximum concentrations 72 hours after infection. The pathogenicity of genetic variants of the SARS-CoV-2 virus for BALB/c mice has been assessed, a 50 % infectious dose for intranasal infection (ID50) determined. Histological analysis showed COVID-19-specific lung tissue lesions in infected animals. Our study proves that BALB/c mice can be used as a model animal in screening studies when evaluating the effectiveness of therapeutic, vaccine preparations and studying the pathogenesis caused by VOC of the SARS-CoV-2 virus: Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Omicron (B.1.1.529) and the like.

Introduction. The novel coronavirus infection COVID-19 is a major public health problem worldwide. Several publications show the presence of gastrointestinal (GI) symptoms (nausea, vomiting, and diarrhea) in addition to respiratory disorders. The aim of this study was the monitoring of RNA of COVID-19 pathogen, coronavirus SARS-CoV-2 (Coronaviridae: Coronavirinae: Betacoronavirus; Sarbecovirus) in children hospitalized with acute intestinal infection (AII), with following molecular-genetic characterization of detected strains. Material and methods. Fecal samples of children with AII hospitalized in infectious hospital of Nizhny Novgorod (Russia) in the period from 01.07.2020 to 31.10.2021 were used as material for the study. Viral RNA detection was performed by real-time polymerase chain reaction (RT-PCR). The nucleotide sequence of S-protein gene fragment was determined by Sanger sequencing. Results and discussion. SARS-CoV-2 genetic material was detected in 45 out of 2476 fecal samples. The maximum number of samples containing RNA of the virus occurred in November 2020 (detection rate of 12.2%). In 20.0% of cases, SARS-CoV-2 RNA was detected in combination with rota-, noro-, and adenoviruses. 28 nucleotide sequences of S-protein gene fragment complementary DNA (cDNA) were determined. Phylogenetic analysis showed that the studied SARS-CoV-2 strains belonged to two variants. Analysis of the S-protein amino acid sequence of the strains studied showed the absence of the N501Y mutation in the 2020 samples, which is a marker for variants with a high epidemic potential, called variants of concern (VOC) according to the World Health Organization (WHO) definition (lines Alpha B.1.1.7, Beta B.1.351, Gamma P.1). Delta line variant B.1.617.2 was identified in two samples isolated in September 2021. Conclusion. The detection of SARS-CoV-2 RNA in the fecal samples of children with AII, suggesting that the fecal-oral mechanism of pathogen transmission may exist, determines the necessity to optimize its monitoring and to develop an algorithm of actions with patients with signs of AII under the conditions of a novel coronavirus infection pandemic.

Введение. В настоящее время продолжается активный поиск эффективных вакцин от коронавируса SARS-CoV-2. Цель. Провести анализ литературы и оценить состояние активных разработок вакцин от SARS-CoV-2. Материал и методы. Проанализированы русскоязычные и англоязычные источники литературы по проблеме поиска эффективной вакцины от SARS-CoV-2. Результаты. В качестве базовых соединений для разработки вакцин проанализированы структурные белки коронавируса. Показано, что белок S – идеальная структура для создания вакцин, эффективно индуцирующих синтез нейтрализующих антител и обеспечивающих формирование иммунитета. Получены сведения о современных направлениях разработки вакцин. Выводы. Вирус SARS-CoV-2 продолжает мутировать, что приводит к появлению новых высококонтагиозных штаммов, таких как «Дельта», «Омикрон». В связи с этим необходимы дополнительные исследования и клинические испытания, чтобы подтвердить эффективность имеющихся вакцин против SARS-CoV-2 либо продолжить разработку новых вакцин.

Background. Prescribing antibacterial drugs for the treatment of a new coronavirus infection at the outpatient stage is often unreasonable and can also lead to an aggravation of the patient’s condition due to the effect of this group of drugs on the intestinal microflora and lead to other undesirable effects.The aim: to assess the level of lipopolysaccharide-binding protein and indicators of systemic inflammation in patients with moderate viral SARS-CoV-2 lung disease on the background of antibiotic therapy.Materials and methods. 60 patients hospitalized in the infectious diseases department with a positive PCR result for SARS-CoV-2 in the age group 44–70 years old were examined. The patients were divided into 2 groups: group 1 (n = 26) – patients who did not receive antibacterial drugs at the outpatient stage, group 2 (n = 34) – patients who received antibiotic therapy. The control group was also selected (n = 20). Patients underwent a study of the level of lipopolysaccharide-binding protein (LBP), ferritin and C-reactive protein in the peripheral blood.Results. In the group of patients with new coronavirus infection who were admitted to the inpatient stage of treatment and received antibacterial therapy at the outpatient stage, a significantly higher levels of LBP – 37.3 [13.8; 50.4] µg/ml (p˂0.05) and ferritin – 276.00 [184.00; 463.00] µg/ml (p˂0.05) were revealed, compared with group 1 and the control group.Conclusions. In the group of patients who received antibiotic therapy at the outpatient stage, a significantly higher level of LBP was revealed compared to the group in which this group of drugs was not used. These results indicate the possible impact of uncontrolled and early intake of antibacterial drugs on the gut microbiome and intestinal permeability, and also prove the need for a more responsible approach to the choice of starting therapy for new coronavirus infection.

The aim of the study – systematization and analysis of information on the prevalence of SARS-CoV-2 virus variants according to information databases and own cross-sectional studies. Materials and methods. The analysis was conducted in the period 2020–2021 using information databases and research resources: Google Scholar, Cochrane Library, Scirus, Springer, Medline, Embase, PubMed, Web of Science. Our own examination included a total of 80 nasopharyngeal swabs (at least two specimens in each case) collected from ARVI symptomatic or suspected COVID-19 patients, who were treated at the MNE KRC “Regional Clinical Infectious Diseases Hospital” from June to October 2021 and tested positive on SARS-CoV-2. The first study was performed in the inter-peak period, and the second one – on the rise of the disease. A real-time polymerase chain reaction (PCR) method was used for primary identification with the diagnostic kit “Biocore® SARS-CoV-2” (LLC “Biocor Technology Ltd.”, Ukraine) in accordance with the manufacturer’s instructions. Multiplex analysis SNPsig® VariPLEX™ Covid-19 (Primerdesign™ Ltd., UK) was used in the first cross-sectional study for secondary identification. Results. Systematization and analysis of the prevalence of SARS-CoV-2 variants according to information databases were performed. According to the results of our cross-sectional studies on SARS-CoV2 variants circulating in the Kharkiv region in June – October 2021, the complete replacement of the alpha variant, which was dominant in June – 87.5 %, with the delta variant – 95.0 %. All patients had signs of respiratory failure, community-acquired pneumonia was visualized instrumentally (computed tomography, radiography, ultrasound) at the first study in 90 % of cases, and at the second – in 100 %. The median age of patients was 60.4 years (minimum – 25 years, maximum – 91 years) during the first study, but during the second – 52.6 years (minimum – 18 years, maximum – 84 years). Thus, the more aggressive and contagious delta variant has become dominant requiring thorough public health anti-epidemic measures. Conclusions. Monitoring and control of the virus evolution using epidemiological studies, viral genetic sequence, as well as laboratory PCR are necessary to prevent the spread of COVID-19, to study the effectiveness of test systems and optimize diagnosis and etiotropic therapy as well as vaccine modifications.

Introduction: Currently, low molecular-weight compounds are being developed as potential inhibitors of CoVs replication, targeting various stages of the replication cycle, such as major protease inhibitors and nucleoside analogs. Viroporins can be alternative protein targets. The aim of this study is to identify antiviral properties of histidine derivatives with cage substituents in relation to pandemic strain SARS-CoV-2 in vitro., Materials and Methods: Combination of histidine with aminoadamantane and boron cluster anion [B10H10]2 (compounds IIV) was carried out by classical peptide synthesis. Compound were identified by modern physicochemical methods. Antiviral properties were studied in vitro on a monolayer of Vero E6 cells infected with SARS-CoV-2 (alpha strain) with simultaneous administration of compounds and virus., Results: Derivatives of amino acid histidine with carbocycles and boron cluster were synthesized and their antiviral activity against SARS-CoV-2 was studied in vitro. Histidine derivatives with carbocycles and [B10H10]2 have the ability to suppress virus replication. The solubility of substances in aqueous media can be increased due to formation of hydrochloride or sodium salt., Discussion: 2HCl*H-His-Rim (I) showed some effect of suppressing replication of SARS-CoV-2 at a viral load of 100 doses and concentration 31.2 g/ml. This is explained by the weakly basic properties of compound I., Conclusion: The presented synthetic compounds showed moderate antiviral activity against SARS-CoV-2. The obtained compounds can be used as model structures for creating new direct-acting drugs against modern strains of coronaviruses.

The aim of the review: to present up-to-date scientifically based information about the laboratory parameters of patients associated with severe SARS-CoV-2 infection and internal organ damage. Materials and methods: full-text publications of clinical, randomized and cohort studies, systematic reviews and meta-analyses from scientific databases PubMed, Elsevier, Scopus, Google Scholar, E-library for the period from 2019 to 2022 were analyzed. Results. Specific biomarkers were identified, including inflammatory and immunological parameters (C-reactive protein, procalcitonin, IL6), hematological (number of lymphocytes and neutrophils, NLR, D-dimer, ferritin, RDW), myocardial (troponin, creatinekinase-MB, myoglobin), hepatic (AST, ALT, total bilirubin, albumin) and characterizing lung injury (KL-6), which can be used for risk stratification, as prognostic biomarkers of adverse clinical consequences, including death in patients with COVID-19. The studies demonstrated new biomarkers of inflammatory and systemic manifestations of COVID19: procalcitonin, calprotectin and presepsin.

Recently, almost all over the world attention of doctors and scientists is focused on a new coronavirus infection, the source of which was the causative agent SARS-CoV-2. In this regard, early diagnosis, including on the basis of symptoms from ENT organs, is crucial. A brief analysis of the available literature on the peculiarities of ENT organs manifestations in patients with SARS-CoV-2 is given. It was found out that to date there is very little data on the state of loro organs in patients with SARS-CoV-2 and no data on anosmia in the pediatric population. However, it is in children in the epidemic aspect that early diagnosis of infection and understanding of its key symptoms is of utmost importance.

Aim. To study the impact of coronavirus disease 2019 (COVID-19) pandemic on hospitalization rates, diagnosis, and outcomes of infective endocarditis (IE) with a subanalysis of IE course in combination with COVID-19.Material and methods. This prospective cohort study included 168 patients with definite or probable IE (DUKE 2015) hospitalized in the V.V. Vinogradov City Clinical Hospital from July 2017 to July 2022. All patients underwent a conventional examination in accordance with current clinical guidelines. We studied clinical, paraclinical and etiological parameters, as well as outcomes.Two clinical observations of the combination of IE and COVID-19 are presented.Results. When assessing the local registry of patients with IE, a trend towards an increase in hospitalizations rate of IE in 2021-2022 was shown, with a decrease during the period of long-term lockdowns in Moscow and a subsequent surge after their cancellation. Patients with IE during the COVID-19 pandemic had a more favorable clinical profile, a 2-fold increase in IE diagnosis (due to late hospitalization), frequent detection of Staphylococcus aureus MSSA (32,6%), and frequent surgical treatment (up to 87,6% with a combination of IE and COVID-19), as well as high in-hospital mortality, but without a tendency to increase (30,4%). Clinical observations of IE and COVID-19 combination are presented, which demonstrates the contribution of COVID-19 as the only risk factor for native tricuspid valve IE in a patient without predisposing causes, as well as a factor in the unfavorable prognosis for native aortic valve IE after the addition of COVID-19, which led to lethal outcome.Conclusion. The present study demonstrates the profile of patients with IE and COVID-19 depending on the epidemiological situation of COVID-19 and the association with SARS-CoV-2 infection. The data obtained make it possible to discuss the potential relationship between COVID-19 and IE. The "endocarditis team" determines the timely implementation of surgery and the absence of an increase in inhospital mortality, regardless of the epidemiological situation.

Introduction: The current epidemiological situation dictates a detailed study of the effect of a new coronavirus infection (SARS-CoV-2) on various anatomical, histological, physiological and biochemical parameters of the human body, which has become an integral part of many medical research, including urology, andrology, endocrinology., Objective: To study serum testosterone levels and testicular hemodynamics before and after infection with SARS-CoV-2., Materials and Methods: 20 patients were examined, before and after suffering SARS-CoV-2 infection (who fell ill at the beginning of 2020). Average age 37.8 years (min=27, max=50). The level of total testosterone (s) in the blood serum and hemodynamic parameters of the testicles (maximum and minimum blood flow velocity and resistance index) were studied., Results: When studying the level of s 3 months after the transferred SARS-CoV-2, its decrease from the initial value was noted (r=0.47; p=0.35), and after 6 months (r=0.98; p<0.007) there was no recovery of the target level of Ts before infection with SARS-CoV-2. Regarding the hemodynamics of the testicles, there was also a decrease in Vmax and Vmin, and an increase in RI, which indicates a deterioration in the blood flow of the testicles (p<0.001)., Conclusion: SARS-CoV-2 affects the level of Ts in the blood serum and the parameters of the hemodynamics of the testicles. The extent to which SARS-CoV-2 affects patient performance depends largely on the severity of the disease and to a lesser extent on baseline performance.

Introduction. The third wave of the new coronavirus infection (COVID-19) pandemic warrants total mobilisation of healthcare and social resources. In this respect, a pressing issue remains the provision of routine and emergency surgical care in patients with hepatopancreatobiliary diseases.Materials and methods. A retrospective analysis of the surgical outcomes in 5,040 hepatopancreatobiliary patients was carried out; this accounted for 51.1 % of the total abdominal surgeries.Results and discussion. Biliary lithiasis and its complications — choledocholithiasis with obstructive jaundice and residual choledocholithiasis — (54.4 %) as well as acute calculous cholecystitis (18.7 %) were operated most frequently. A sharp decrease over all hepatopancreatobiliary nosologies was registered for the surgical interventions in first pandemic year 2020. Thus, the median annual number of operations for biliary lithiasis and its complications was 550 (482–592 year-range) in the precovid period, while dropping to only 321 at the onset of pandemic (p

Autopsy material and medical history were studied and analyzed in a 20-year-old male patient who had died from COVID-19 infection with the development of acute SARS-CoV-2-associated hemorrhagic necrotizing encephalopathy in adults with obvious endothelial dysfunction confirmed by virological examination of the autopsy material. In this case, the brain structures displayed the main found histopathologic signs: widespread vasculitis (endotheliitis) with varying degrees of segmental and total endothelial destruction; thrombosis mainly of the vessels of the microcirculatory bed; parenchymal hemorrhagic necrosis and inflammation (encephalitis); severe necrobiotic damage to neurons. Cerebrovascular immune damages and hypercoagulable states, which were observed in some acute viral neuroinfections, are the basis for the neurological complications of COVID-19. In this case of bicausal diagnosis (the presence of a comorbidity), the primary disease contributed to the acute progression of the background disease (secondary infiltrative tuberculosis with the development of specific pleuritis and pneumothorax with the addition of acute bilateral focal confluent bronchopneumonia with a history of undifferentiated immunodeficiency syndrome. Emphasis is laid on the possibility and importance of involving the brain structures in the process in COVID-19 for the timely diagnosis of emerging neurological disorders. A brief literature review is given.

With the onset of the COVID-19 pandemic, a number of molecular-based tests have been developed to diagnose SARS-CoV-2 infection. However, numerous available serological tests lack sufficient sensitivity or specificity. They do not detect specific antibodies in a significant proportion of patients with PCR-confirmed COVID-19. There is evidence that some convalescents have a relatively short-lived humoral immunity. In contrast, a number of publications have shown that T-cell response to human coronaviruses, including SARS-CoV-1, MERS, and SARS-CoV-2, can be strong and long-term. Assessment of T-cell immunity to SARS-CoV-2 is important not only for stratification of risks and identification of potentially protected populations with immunity acquired as a result of previous infection, but also for determining immunogenicity and potential efficacy of vaccines under development. The existing methods of quantitative or semi-quantitative assessment of specific T-cell response are mainly used in scientific research and are not standardised. The aim of the study was to develop and verify experimentally a test kit to be used in a standardised procedure for in vitro determination of T-cells specific to SARS-CoV-2 antigens, in human peripheral blood. Materials and methods: the TigraTest® SARS-CoV-2 kit developed by GENERIUM, which determines the number of T-cells secreting interferon gamma in vitro, was tested in the study. Samples of venous blood of volunteers from three different groups were analysed in the study: presumably healthy volunteers; COVID-19 convalescents; individuals vaccinated against SARS-CoV-2. Results: the authors developed the TigraTest® SARS-CoV-2 kit for in vitro determination of T-cells specific to SARS-CoV-2 antigens in human peripheral blood, demonstrated its specificity and performed preliminary assessment of its sensitivity. The study analysed the range and magnitude of the T-cell response in convalescent and vaccinated individuals. A pronounced T-cell response was also shown in some individuals with no symptoms or with unconfirmed diagnosis. It was discovered that the mean T-cell response to peptides of the spike protein (S-protein) was higher in the vaccinated individuals than in the convalescent patients. A correlation was determined between the severity of the disease and the level of T-cell response. Specific contributions of various groups of antigens to the T-cell response after COVID-19 infection were also determined. Conclusions: the TigraTest® SARS-CoV-2 kit is a specific and sensitive tool for the assessment of T-cell immunity to the SARS-CoV-2 virus, which can also be used for vaccinated individuals. The kit may be used in clinical practice for comprehensive assessment of immunity to SARS-CoV-2.

Aim. Analyse available literature data about the possibility of coronavirus infection with and the severity of the course of infection in various animal species in order to evaluate the significance of this possibility in the context of preservation of the well‐being of both wild and domestic animals.Discussion. SARS‐CoV‐2 is thought to have originated from bat CoV. The virus enters the cell by binding to the ACE2 receptor, the affinity for which differs depending on the animal species. Infected animals show viral RNA and may show clinical symptoms. It is known that the virus originated from some animals, while others may be carriers. Moreover, it can be that wild as well as domestic and farm animals are in close contact with humans. Therefore, it is advisable to conduct a study of the degree of threat to humans associated with the persistence of the virus in animal communities.Conclusion. There is ample literature on the possibility of infection in various animals. However, it is not enough to fully understand how significant is the role that animals can play in the spread of coronavirus infection among humans and how much harm it can bring to themselves.

Relevance. The research of the dynamics of population immunity formation is an important component of epidemiological surveillance, especially during the pandemic period. Identifying the features of the course of the epidemic process of a particular infection provides an opportunity to make the right decisions both in the fight against the disease and in its prevention. Aims. Evaluate the dynamics of the formation of collective immunity in the population of the city of Moscow. Materials & Methods. The presence of immunity in the population was assessed by immunochemiluminescent analysis of blood serum of patients for the presence of antibodies IgM and IgG to SARS-CoV-2. Results. During the analysis of the annual dynamics of IgM detection, a gradual decrease in this indicator was recorded. The dynamics of the combined detectability of IgM/IgG has a wave-like course. It should be noted that the curves of the dynamics of the IgM detectability and the combined IgM/IgG detectability reflect multidirectional trends: the summer rise in the IgM detectability coincides with the fall and the lowest values of the IgM/IgG detectability indicator. Afterwards, the decrease in the IgM detectability is accompanied by an increase in the combined IgM / IgG detectability. Detectability of IgG has a pronounced tendency to rise with short time intervals of decline. In the first three months of testing, a gradual decrease in detectability was recorded from 15.2 to 10.8%. However, since August, there has been a new increase in detectability of IgG to 45.5% in marth and subsequent stabilization in the range of 44.3–45.5%. Conclusions. The level of seroprevalence for the period of May 2021 is 44.3%. Detection during screening of patients with IgM and partially with a combination of IgM / IgG may indicate the presence of a significant hidden component of the epidemic process, which may lead to an increase in morbidity.

The pandemic caused by the SARS-CoV-2 virus (COVID-19) made it necessary to evaluate in more detail the processes of neuroinflammation as an integral component of the pathogenesis of viral infection. The acute neuroinflammatory response includes the activation of resident tissue macrophages in the CNS and the subsequent release of various cytokines and chemokines, which probably activates oxidative stress, causing long-term neuronal damage. This makes urgent the search for drugs with indirect anti-inflammatory effects with proven effectiveness. From this point of view, it is worth further studying the treatment of patients with COVID-19 with dipyridamole, which, with its antiviral activity and anti-inflammatory effect, inhibiting acute inflammation and progressive fibrosis, is the drug of choice, especially for patients with early signs of elevated D-dimer concentrations and pronounced clinical symptoms of microangiopathy.

Acute cerebrovascular accidents (ACVIs) associated with COVID-19 coronavirus infection are one of the most talked about problems in the medical community. To date, the true incidence of stroke in patients with COVID-19 remains unclear. So far, the published literature has been limited to case reports, case series, and observational cohort studies. The article analyzes possible risk factors, especially the age of patients, pathogenetic and clinical correlations of ACVA and SARS-CoV-2 (COVID-19). A clinical case of an 82-year-old patient with ischemic stroke and COVID-19 infection is described.

Introduction. Verification of histological changes in respiratory system using Syrian (golden) hamsters (Mesocricetus auratus) as experimental model is an important task for preclinical studies of drugs intended for prevention and treatment of the novel coronavirus infection COVID-19. The aim of this work was to study pathological changes of pulmonary tissue in SARS-CoV-2 (Coronaviridae: Coronavirinae: Betacoronavirus; Sarbecovirus) experimental infection in Syrian hamsters. Material and methods. Male Syrian hamsters weighting 80–100 g were infected by intranasal administration of culture SARS-CoV-2 at dose 4 × 104 TCID50/ml (TCID is tissue culture infectious dose). Animals were euthanatized on 3, 7 and 14 days after infection, with gravimetric registration. The viral load in lungs was measured using the polymerase chain reaction (PCR). Right lung and trachea tissues were stained with hematoxylin-eosin and according to Mallory. Results and discussion. The highest viral replicative activity in lungs was determined 3 days after the infection. After 7 days, on a background of the decrease of the viral load in lungs, a pathologically significant increase of the organ’s gravimetric parameters was observed. Within 3 to 14 days post-infection, the lung histologic pattern had been showing the development of inflammation with a succession of infiltrative-proliferative, edematousmacrophagal and fibroblastic changes. It was found that initial changes in respiratory epithelium can proceed without paranecrotic interstitial inflammation, while in the formation of multiple lung parenchyma lesions, damage to the epithelium of bronchioles and acinar ducts can be secondary. The appearance of epithelioid large-cell metaplastic epithelium, forming pseudoacinar structures, was noted as a pathomorphological feature specific to SARS-CoV-2 infection in Syrian hamsters. Conclusion. As a result of the study, the specific features of the pathology of the respiratory system in SARSCoV-2 infected Syrian hamsters were described. These findings are of practical importance as reference data that can be used for preclinical studies to assess the effectiveness of vaccines and potential drugs.

In 2020–2021, the world was engulfed by the pandemic of a new coronavirus infection (COVID-19) caused by the SARS-CoV-2 virus. The low population coverage with vaccination against COVID-19 and the lack of herd immunity result in the need to find an effective and safe etiotropic treatment. Medicinal agents for treatment of COVID-19, approved while preparing this publication, have several limitations related to the conditions of their use and/or population category. In this situation, interferon-containing drugs widely used in Russia and the CIS for prevention and treatment of viral infectious diseases, i.e. ARVI and influenza, may hold promise. This study aims to confirm in vitro antiviral activity against SARS-CoV-2 for the preparation VIFERON® containing recombinant human interferon alpha-2b (IFNα-2b). Materials and methods. Vero CCL-81 cells were infected with hCoV-19/StPetersburg-RII3524VR4/2020 strain of SARS-CoV-2 at doses of 10 TCID50 or 100 TCID50 per well. The suppressive effect of IFN-2b, extracted from VIFERON® in dosage form of rectal suppositories, was evaluated by qRT-PCR at 24 h and 48 h after the infection of cells in two schemes, simulating preventive (24 h before infection) and therapeutic (2 h after infection) use of drugs. Results. IFNα-2b at concentrations of 800, 400, 200, 100 and 50 IU/ml, extracted from rectal suppositories of VIFERON®, showed high biological activity, displayed as inhibition of SARS-CoV-2 strain replication in both infectious doses evaluated either at 24 h or at 48 h after cell infection. The “preventive” vs. “therapeutic” scheme was found to be more effective. In the “preventive” scheme the virus titre decreased by more than 3 lg TCID50 at 24 hours post-infection and by 5–6 lg TCID50 at 48 hours post-infection after administration of 800 IU/ml IFNα-2b. Conclusion. The study results evidence that VIFERON® in dosage form of rectal suppositories may be promising for prevention and treatment of new coronavirus infection in clinical practice.

Along with efficacy and safety, it is extremely important to study the severity of humoral and cellular immunity during not only vaccination, but also revaccination against the Severe Acute Respiratory Syndromerelated CoronaVirus 2 (SARS-CoV-2).Aim. To compare the immunogenicity (humoral and cellular immunity) of various (heterologous and homologous) revaccination regimens against coronavirus disease 2019 (COVID-19) in a prospective observational study.Material and methods. In individuals aged ≥18 years, in the absence of contraindications to vaccination, two following types of vaccines were used for primary vaccination and revaccination: Gam-COVIDVac and CoviVac. Group I patients received Gam-COVID-Vac at each stage of primary and secondary vaccination; patients of group II — Gam-COVID-Vac at each stage of primary vaccination, CoviVac at each stage of re-vaccination; patients of group III — CoviVac at each stage of primary vaccination and Gam-COVID-Vac at each stage of revaccination; patients of group IV — CoviVac at each stage of primary and secondary vaccination. All participants (at each stage of vaccination, revaccination and 12 months after the primary vaccination) were determined the level of IgG to the receptor-binding domain of SARS-CoV-2 spike (S) protein and T-cell immunity to SARSCoV-2.Results. The maximum level of IgG at the second stage of revaccination was observed in groups I and III. In addition, in groups I, III and IV, a significant (p8). At the same time, the level of active T cells responding to SARS-CoV-2 nucleocapsid Ag stimulation by Visit 4 (stage II of revaccination) was noted in groups II (14,5) and IV (12).Conclusion. The use of the Gam-COVID-Vac vaccine as a booster dose in both homologous and heterologous vaccination regimens against the SARS-CoV-2 virus is most effective for stimulation and humoral and T-cell post-vaccination response.

Coronavirus infection caused by the SARS-CoV-2 virus is an extremely important and urgent problem of modern medicine. It spreads quickly, has a high probability of a severe course and a large number of critical complications in patients from the risk group. The presence of pathognomonic symptoms, one of which is the development of hypo– or anosmia, makes it possible to quickly differentiate coronavirus infection from other acute respiratory viral infections, that is, to isolate the patient on time and begin correct treatment, taking all possible risks into account. The aim is to identify the morphological features of olfactory structural elements in patients with coronavirus disease (COVID-19) for a better understanding of the mechanisms of olfactory disorders development in coronavirus infection. Materials and methods. The basis of the work is a retrospective analysis of autopsy material, namely the mucous membrane of the upper parts of the nasal cavity (olfactory epithelium) and olfactory bulbs of nine deceased (4 women and 5 men) aged from 53 to 79 years with a laboratory-confirmed diagnosis of COVID-19 and anosmia in anamnesis. We used standard hematoxylin and eosin staining and immunohistochemical reactions in accordance with the TermoScientific protocols (USA) with antibodies to neurospecific beta-III tubulin (clone TuJ-1) and RnDsystems protocols with antibodies to olfactory marker protein (OMP) and angiotensin converting enzyme (ACE-2). To compare the results, a control group of 9 deaths (3 women and 6 men) aged from 59 to 68 years with a laboratory-refuted diagnosis of COVID-19 was formed. The causes of death of these patients were complications of diabetes, coronary heart disease and cerebrovascular disorders of the ischemic type. Results. The average age of the deceased with a laboratory-confirmed diagnosis of COVID-19 and a history of anosmia and the control group was 64.67 ± 7.73 and 62.33 ± 6.48 years, respectively. The expression of olfactory marker protein (OMP) and neurospecific beta-III tubulin (clone TuJ-1) was partially positive (40.89 (25.00–52.00) and 42.44 (29.00–55.00) cells in the field of view at a magnification of 200×, respectively) in seven out of nine sections of the olfactory mucous membrane of deaths with a laboratory-confirmed diagnosis of COVID-19 and anosmia in anamnesis. The reaction with antibodies to angiotensin converting enzyme (ACE-2) was focally or subtotally absent (34.33 (14.00–49.00) cells in the field of view at 200× magnification). There was expression of these three markers in control sections of the olfactory mucosa of a deceased with a laboratory excluded diagnosis of COVID-19 and no symptoms of anosmia (Mann–Whitney test, P < 0.05). In sections of olfactory bulbs of patients with COVID-19 weak (Mann–Whitney test, P < 0.05) expression of receptors for angiotensin-converting enzyme (ACE-2) (26.78 (15.00–39.00) cells in field of view at a magnification of 200×) was revealed in contrast to control sections (100.56 (94.00–107.00) cells in the field of view at a magnification of 200×). Conclusions. The development of anosmia in SARS-CoV-2 coronavirus infection has specific features. This may be due to the primary destruction of cells expressing receptors for the angiotensin-converting enzyme (ACE-2-positive: sustentacular cells of the olfactory mucosa, neurons of the olfactory bulbs). Subsequent dysfunction of olfactory cells (OMP- and TuJ-1-positive) is also possible.

The new coronavirus SARS-CoV-2 has become a global challenge to medicine and, in particular, laboratory diagnostics. The study of the antibodies’ level to SARS-CoV-2 can be used as a confirmation test in the diagnosis of a disease, but it becomes of paramount importance in assessing population immunity resulting from a disease or vaccination, as well as in selection of convalescent plasma donors. The kits developed in our country and abroad for detecting antibodies to the SARS-CoV-2 virus differ both in the methods of testing and in the used coronavirus antigens to which the antibodies are directed. The aim of this study was to compare the diagnostic sensitivity and specificity of five kits for the detection of IgG antibodies to the SARS-CoV-2 virus, based on different diagnostic methods. Serum samples from 137 COVID-19 convalescents and 166 donors of blood and its components were examined. The control group consisted of 50 blood sera collected at the beginning of 2019 and 19 sera collected in 2018 (before the advent of the SARS-CoV-2 virus) and stored at -70 °C. Testing was carried out in analytical systems: rapid test “COVID-19 IgM/IgG Rapid Test (Colloidal Gold)” (China), on an automatic immunochemical analyzer Abbott Architect™ i2000 and kit “SARS-CoV2-IgG” (Abbot, Chicago , IL USA), by the chemiluminescence method using an automatic analyzer of the CL series and kits of the “Mindray” company (China) “SARS-CoV-2 IgM” and “SARS-CoV-2 IgG” and by the enzyme immunoassay method on the kits of the companies “Diagnostic Systems” Ltd (Russia, Nizhny Novgorod) “DS-IFA-ANTI-SARS-CoV-2-G”, “Xema” Ltd (Federal State Budgetary Institution “National Medical Research Center of Hematology” of the Ministry of Health of Russia) “SARS-CoV-2-IgG-IFA” and “Vector-Best” CJSC (Russia, Novosibirsk)” SARS-COV-2-IgM-IFA-BEST” and “SARS-COV-2-IgG-IFABEST”. When comparing the results of testing 137 plasma samples on the Vector-Best and Mindray kits for IgG antibodies, 127 samples were positive, 7 samples were negative on both kits, the discrepancy was 2.2%. In the study of IgM antibodies, 32.1% were positive, and 52.6% were negative in both kits. The discrepancy rate was 15.3%. Out of 166 samples, 1 serum (0.6%) was negative in 5 kits. On the Mindray kit, IgG antibodies to the antigens of the SARS-CoV-2 virus were detected in 165 samples (99.4%), on Vector-Best – in 164 sera (98.8%), on Diagnostic systems – in 151 (90.96%), on Xema – in 154 (92.8%), and on Abbott – in 155 samples (93.4%). At the same time, 135 (81.33%) samples were positive in all kits, while 30 samples had discordant results (18.07%), and in 9 sera, specific IgG was not detected in 2 or more kits. ROC analysis revealed a high diagnostic value of all tested kits (AUC from 0.908 to 0.998), which indicates a high quality of the separation model of positive and negative samples (p < 0.001). With the cut-off set by the manufacturers, the sensitivity and specificity ranged from 82.8% and 93.3% for the Diagnostic Systems kit to 99.4% and 95.8% for the VectorBest kit. The calculated correlation coefficients were higher between kits with a similar composition of the antigen used in the kits; therefore, it is better to monitor the dynamics of antibodies by diagnostic kits from the same manufacturer.

Описано клінічний перебіг, особливості діагностичних обстежень та труднощі у верифікації нової нозології — мультисистемного запального синдрому, асоційованого із SARS-CoV-2, у дівчинки віком 15 років. Дівчинку доставлено до Київської обласної дитячої лікарні № 2 із скаргами на підвищення температури тіла, виражений інтоксикаційний синдром, загальну слабкість, запаморочення голови, відсутність сечі протягом доби. Дитину оглянуто консиліумом лікарів, обстежено лабораторно та інструментально, після ретельно зібраного епідеміологічного анамнезу виявлено можливий контакт із хворим на коронавірусну інфекцію за місцем навчання та встановлено ймовірний випадок мультисистемного запального синдрому, асоційованого з SARS-CoV-2. За результатами власних спостережень під час пандемії, ця нозологія спостерігається у хворих, які перехворіли на коронавірусну інфекцію в клінічній або субклінічній формі та на період госпіталізації мали клінічний симптомокомплекс кавасакіподібних симптомів. Таке захворювання є новим на сьогодні, має різноманітні клінічні прояви та патологічні особливості, що є проблемою для клініцистів. Адже ще не існує уніфікованих протоколів діагностики та лікування MIS-C (мультисистемний запальний синдром), і кожний лікар опирається на власний досвід та описані раніше випадки. Описаний випадок мультисистемного запального синдрому допоможе практикуючим клініцистам на ранніх етапах діагностувати хворобу і надати кваліфіковану допомогу пацієнтам. Дослідження виконано відповідно до принципів Гельсінської декларації. На проведення досліджень отримано інформовану згоду батьків дитини. Автор заявляє про відсутність конфлікту інтересів.

Objective was to investigate the SARS-CoV-2 collective immunity status of the population of Belarus within the context of the COVID-19 pandemic. Materials and methods. The work was carried out according to the methodology for assessing SARS-CoV-2 population immunity, developed by Rospotrebnadzor Russia and the Ministry of Health of Belarus with the participation of the St. Petersburg Pasteur Institute, taking into account WHO recommendations. The Bioethics Committee of Belarus and the local ethics committee of the St. Petersburg Pasteur Institute approved the study. Selection of participants was carried out using a questionnaire method and online technology (internet, cloud server). Volunteers were randomized into seven age groups (years of age): 1–17; 18–29; 30–39; 40–49; 50–59; 60–69; and 70+. Regional randomization ensured proportional representation of volunteers from each region, and no more than 30 people were included from one enterprise. In accordance with manufacturer instructions, blood plasma samples were analyzed for: IgG antibodies (Abs) to the SARS-CoV-2 nucleocapsid (Nc) using a quantitative ELISA test system; and IgG Abs to the receptor binding domain (RBD) of the SARS-CoV-2 S (spike) surface glycoprotein using a qualitative ELISA test system. Statistical processing was carried out using Excel 2010 and other software. Statistical differences were designated as significant when p < 0.05, unless otherwise indicated. Results. The level of seroprevalence, in terms of Abs to Nc among the Belarusian population, was 38.4% (95% CI 37.6–45.4). The highest Ab levels were found among individuals in older age groups (50-70+ years old). The lowest were found in children 1–17 years old and in young people 18–39 years old The distribution of seroprevalence across Belarusian regions was relatively homogeneous, with the exception of the Minsk Region, where a statistically significant decrease in the indicator was noted. In terms of profession, the largest share of seropositive individuals was found among transportation workers; the smallest was found in business. The moderate COVID-19 incidence has not led to a dramatic increase in the number of contacts. The base reproduction number (R0) was 1.3. In the Republic of Belarus, there was a moderate level of asymptomatic COVID-19 among seropositive individuals (45.3% [95% CI 44.0–46.7]). This form of infection was observed most often among children aged 1–17 years old (65.0% [95% CI 61.3–68.6]). In parallel with seroprevalence assessment, SARS-CoV-2 vaccination was carried out. We used two vaccines: Gam-COVID-Vac (also known as Sputnik V, developed by Gamaleya National Center for Epidemiology and Microbiology, Russia); and BBIBP-CorV (Sinopharm, PRC). Vaccination against SARS-CoV-2 was accompanied by an increase in the level of anti-RBD Abs (95% [95% CI 94.7–96.7]). Taking into account the vaccination of a subset of the population with BBIBP-CorV, the overall herd immunity, inferred from the analyzed indicators (presence of anti-Nc or anti-RBD Abs), was 47.1% (95% CI 46.3–48.0). Conclusion. COVID-19 in Belarus was characterized by a moderately pronounced course of the epidemic process. The threshold level of herd immunity to SARS-CoV-2 has not yet been reached, as a result of which the conditions for progression of the epidemic remain.

The objective: to perform quantitative analysis of SARS-CoV-2 viral load (VL) levels in lung tissues in deceased patients with COVID-19 and to evaluate its association with the nature of histological changes in the lungs and the duration of stay in ICU till the lethal outcome.Subjects and Methods. Sections of formalin-fixed and paraffin-embedded lung tissues of 36 deceased patients with COVID-19 were used. The SARS-CoV-2 viral load was quantitatively assessed using the original qPCR. VL was calculated using the following formula: copies SARS-CoV-2 / copies ABL1 × 100, expressed as the ratio of the true number of SARS-CoV-2 cDNA copies per 100 copies of ABL1 gene cDNA.Results. In cases with no histological changes typical of diffuse alveolar lung injury (DAI), the detection rate of SARS-CoV-2 RNA and the average level of the SARS-CoV-2 viral load were 62.5% (5 out of 8 observations) and 104.75 (range 0-313) copies of SARS-CoV-2 cDNA per 100 copies of human ABL1 gene cDNA. The average level of the SARS-CoV-2 viral load in the lungs with prevailing histological changes characteristic of the proliferative and exudative phases of DAI differed by 60 times and amounted to 909 (18-2,657) and 54,924 (834-250,281) copies of SARS-CoV-2 cDNA per 100 copies of human ABL1 cDNA, respectively. The average duration of stay in the intensive care unit in the group of patients with exudative and proliferative phases of DAI was 10.64 (1-22) and 8.14 (1-21) bed-days, respectively. The detection rate of the SARS-CoV-2 RNA in patients with diffuse alveolar lung injury was 100%.

Introduction. Many aspects of the pathogenesis and pathomorphology of pneumonia associated with novel coronavirus require a comprehensive study using modern diagnostic methods.The aim of the study was to study the microbiota of the lower respiratory tract in community-acquired pneumonia associated with SARS-CoV-2, to assess the antibiotic and phage resistance of circulating strains of microorganisms.Materials and methods. The analysis of biosamples from 486 patients undergoing inpatient treatment in five mono-hospitals in Tyumen and Tyumen region with a diagnosis of moderate and severe community-acquired pneumonia was carried out. In almost 90% of cases patients received oxygen therapy, about 8% of patients were connected to ventilators. The inoculation of the cultures with clinical samples was carried out for six months (from April to October 2020). The isolated bacterial strains were identified by mass spectrometry. The resistance to antimicrobial drugs and bacteriophages was assessed for identified isolated.Results. Gram-positive cocci, mainly opportunistic microorganisms of the genus Streptococcus and Candida fungi predominated in the microbiota of the lower respiratory tract of patients diagnosed with community-acquired pneumonia associated with SARS-CoV-2. At the same time, bacteria of the Enterobacteriaceae family and nonfermenting gram-negative bacteria were less common compared to patients without coronavirus infection. In the structure of pathogens, the leading position was occupied by the bacteria K. pneumoniae and Acinetobacter spp. The analysis of the sensitivity of microorganisms to antimicrobial drugs showed the highest resistance rates in strains of Acinetobacter spp., Enterococcus spp., Coagulase-negative Staphylococcus. It has been established that in the group of patients with community-acquired pneumonia associated with SARS-CoV-2, the risk of infection with Streptococcus spp. with high level of antibiotic resistance was 1.5 times higher, and taking into account the 95% confidence interval, the value of this indicator ranged from 1.1 to 2.1 times.Conclusion. The data obtained indicate that the microbiota of the lower respiratory tract in community-acquired pneumonia associated with SARS-CoV-2 is represented mainly by bacteria of the genus Streptococcus, which have a high level of resistance to antimicrobial drugs.

Relevance. The novel coronavirus pandemic is a major burden on public health and healthcare professionals. The study of the prevalence of antibodies among medical workers provides an understanding of the potential risk of transmission of the infectious agent, the level of herd immunity, the introduction of specific immunization and risk stratification in various areas of professional activities.The purpose of this study was to assess the level of specific antibodies to SARS-CoV-2 in the personnel of the medical and sanitary unit, providing the population with outpatient and inpatient medical care.Materials and methods. A study to assess seroprevalence to the SARS-CoV-2 virus was carried out in the Omsk region from September 2020 to December 2020. The study included 2 groups of employees of continuously operating organizations – the main group – employees of the medical and sanitary unit of the city of Omsk (n = 631), the control group consisted of employees of two industrial enterprises in the city of Omsk (n = 1696). The level of class G immunoglobulins to the SARS-CoV-2 virus was determined by enzyme-linked immunosorbent assay.Results. Among medical workers, the proportion of people with a positive reaction to IgG was 73.1% (n = 461; 95% CI 69.5–76.4%). In the control group, the proportion of those who were seropositive was 3.9 times less than that – 18.6% (n = 315; 95% CI 16.8–20.5). Significant differences in seroprevalence in men and women were revealed in medical workers (χ2 = 4.164; p = 0.0413). The highest proportion of seroconversion was found in nursing staff – 85,4% (95% CI 71.6 – 93.1), in doctors – 63.3% (95% CI 55.0–70.9). The highest rate of seroprevalence was found among hospital medical workers – 81.9%, the lowest among employees of the administrative and economic service – 51,8%.Conclusions. The level of specific antibodies to SARS-CoV-2 among medical workers significantly exceeded that of other professional groups, and there was a high proportion of seroconversion among junior medical personnel and in-patient medical unit workers.

Aim. In vitro analysis of the inhibitory activity of dry ethanol extracts of some Artemisia spp. growing in the Novosibirsk region for SARS‐CoV‐2 replication.Materials and Methods. The laboratory strain SARS‐CoV‐2/human/RUS/Nsk‐FRCFTM‐1/2020 was passed on Vero cell culture. Dry ethanol extracts of plant parts (stems, flowers, leaves) of six types of Artemisia were prepared. The types used were: A. vulgaris L.; A. glauca (Pall. Ex Willd.); A. dracunculus L. (from three growth locations); A. absinthium L.; A. frigida Willd.; and A. sieversiana Ehrh. ex Willd. Dry extracts were dissolved in DMSO. In vitro analysis of the inhibitory activity of extracts against SARS‐CoV‐2 (an infectious titer of 103 TCID50/ml) replication was performed in a Vero E6 cell culture. To do this, the method of direct inactivation (neutralization) of virions, as well as schemes of “preventive” and “therapeutic” of cells, were used. Comparison samples were dry ethanol extracts of Inonotus obliquus, Syzygium aromaticum L. and Camellia sinensis L.Results. Extracts of leaves of Artemisia spp. proved to be most effective in direct inactivation of virions. By equal and decreasing activity these are the species: A. vulgaris; A. dracunculus*; A. absinthium; A. dracunculus***; A. dracunculus**; A. frigidа; A. glauca; and A. sieversiana with a 50% effective concentration of range 1.10±0.24 – 11.72±2.89 μg/ml. Extracts of flowers of A. vulgaris, A.glauca, A. dracunculus*, A. dracunculus**, A. dracunculus***, A. frigida and A. sieversiana also contain biologically active substances which act both destructively on virions and after the virus has entered cells. For extracts of stems consistently high values of EC50 were found for A. glauca (6.84±1.35; 7.81±2.00 and 14.06±3.06 μg/ml) according to the results of three experimental schemes.Conclusion. The results obtained can become the basis for the development of inexpensive domestic drugs for the treatment and/or prevention of COVID‐19.

The ongoing coronavirus disease (COVID-19) pandemic over the past three years has caused close attention to the problem of herd immunity, which is understood as: "resistance to the spread of a contagious disease within a population or herd". Collective immunity is formed both as a result of infection (natural spread of the pathogen in a population of susceptible individuals) and as a result of the use of specific vaccines. During the COVID-19 pandemic, both mechanisms for the formation of collective immunity were realized. In the first wave, there was a natural formation of collective immunity to the virus following recoveries from COVID-19 caused by pandemic spread of SARS-CoV-2. Starting from December 2020, the widespread use of specific vaccines against SARS-CoV-2 began in the USA, Great Britain, China, Russia, and a number of other countries. This launched the process of post-vaccination collective immunity formation; its features have depended on the vaccine types implemented. Currently, in those countries where vaccination and revaccination of recovered patients is widely carried out, immunity is "hybrid" in nature. Several commonalities should be noted in the pandemic experience: a somewhat regular, periodic (wavelike) nature of the COVID-19 epidemic process; changes in pathogen genetics in variants in all countries; and expansive mass vaccination programs in many populations. From these, we can draw some conclusions about the general trend for all countries in the formation of collective immunity during the pandemic: At the beginning of the pandemic in 2020, overall population seroprevalence did not exceed 20%. Other findings were: the highest seroprevalence rates were noted in the children's age group; pronounced regional differences were revealed; and the highest indicators were noted among medical workers. Collective immunity developed as a result of infection or illness, and in the majority of seropositive volunteers, it was represented by antibodies to both antigens. At the height of the pandemic in the summer of 2021, population seroprevalence reached 50%. This was due to both a significant number of convalescents and the start of mass vaccination campaigns. In all countries, specific differences in seroprevalence (by age, region, profession) leveled out, leading to more uniformity. During this period, the formation of "hybrid" immunity is clearly prominent, and the proportion of individuals with antibodies to RBD alone increased (due to vaccination with vector vaccines). Later, mass vaccination, as well as involvement of most of the population in the epidemic process due to the emergence of the highly contagious Omicron strain, raised the level of collective immunity to 80-90%. This led to a sharp decrease in COVID-19 incidence in the second half of 2022 in all countries participating in the study. In the later stages of the pandemic (2022-2023), almost 90% of seropositive volunteers had hybrid immunity, reflected as antibodies to both antigens (Nc, RBD).

Serological monitoring of the study of population immunity to the SARS-CoV-2 virus in the context of COVID-19 pandemic is a necessary component in epidemiological surveillance, since population epidemiological wellbeing in a context of COVID-19 is determined by state of population immunity to the SARS-CoV-2 virus. The population herd immunity is the limiting factor in spread of the SARS-CoV-2 virus. Information on the state of population immunity is necessary to make a forecast for development of epidemiological situation, as well as to plan measures for specific and non-specific prevention of COVID-19. In this regard, the study of population immunity during the pandemic is necessary to predict development of the epidemic and identify features of epidemic process in any certain region and in the country in general. In May 2020, the Rospotrebnadzor program “Assessment of population immunity to the SARS-CoV-2 virus in the population of the Russian Federation in the context of the COVID-19 pandemic” was developed taking into account WHO recommendations in the format of a longitudinal cohort study with age stratification: at the first stage, a cohort of volunteers is formed; at the second and subsequent stages, the cohort of volunteers formed at the first stage is subject to examination; the number of stages depends on the epidemiological situation. In addition to age-related randomization while forming a cohort, at the first stage, the principle of population coverage uniformity was observed, the participation of volunteers from one institution was excluded, and the use of donated blood or patient blood from medical organizations was excluded. The survey was carried out among 7 age groups of healthy children and adults, regardless present or absent previous COVID-19 disease. Due to the fact that the population study is carried out in the context of COVID-19 pandemic, the optimal timing for collecting biomaterial at each stage is no more than 5–7 days. Questioning, selection of volunteers, their registration for blood donation, as well as processing of the results at the first stage, as well as the implementation of the second and subsequent stages of the Program are carried out only by using cloud service technology. This Program and the technology for its implementation have been successfully tested in 26 regions of the Russian Federation during the implementation of four stages from June 2020 to March 2021. Thus, at present, Rospotrebnadzor has developed a methodology and created an effectively working system of serological monitoring to assess level of herd immunity in different regions of the Russian Federation to predict the epidemiological situation, develop recommendations, and plan vaccination.

The aim. To analyze the blood levels of endothelin-1 (ET -1) and high molecular weight kininogen (HMWK) in patients with breast cancer (BC) previously infected with the new coronavirus.Material and methods. The study group included 20 patients with stage II -IV BC (invasive carcinoma). All patients were receiving chemotherapy at the time of their SA RS-CoV-2 infection. The comparison group included 19 women without breast cancer, who were matched for age. All women of both groups had an RT-PC R confirmed SA RS-Cov-2 infection. Blood levels of ET -1 and HMWK were measured by ELISA 3–10 weeks after the positive antigen test results. The control group included 10 women of the same age without cancer and without CO VID -19 symptoms and anti-SA RS-CoV-2 antibodies.Results. The ET -1 levels in the comparison group were within the reference range, while HMWK levels were significantly higher than those in breast cancer patients. In BC patients with lung metastases, the ET -1 levels were higher than those in the comparison group patients, while in others (no history of lung metastases, with mild infection course or pneumonia), the ET -1 levels were similar to those in the comparison and control groups. The HMWK levels in the study and comparison groups were significantly higher than those in controls. Among BC patients, there were women who had significantly higher ET -1 and HMWK levels compared to the reference levels, and the majority of these patients had lung metastases and previous CO VID -19 pneumonia.Conclusion. The measurement of HMWK blood levels demonstrated that the plasma contact activation system and the kallikrein-kinin system were active for a long period after the infection both in BC patients and in women without cancer. A high level of ET -1, the endothelial dysfunction marker, persisted for a long time in some BC patients. Our results were consistent with results of other studies supporting the hypothesis that SA RS-CoV-2 virus infection is a systemic vascular disease with long-term consequences, and its mechanisms require further study.

Children's multi-system inflammatory syndrome PIMS-TS is a completely new challenge for pediatricians, which has established a separate branch of the fight against the still active COVID-19 pandemic. It turns out that even a pediatric patient who has not suffered symptomatic infection with the SARS-CoV-2 virus, as a result of contact with this pathogen, can develop a severe systemic inflammatory reaction rich in symptoms originating in almost every system of the human body. The first reports of the inflammatory syndrome that is the subject of this work come from May 2020. It is known that the symptoms of PIMS are caused by a multi-system inflammatory response in the body, potentially related to the immune system. The course of this disease may bring to mind other inflammatory diseases in children, such as Kawasaki disease, toxic shock syndrome and MAS macrophage activation syndrome.

Pharyngitis is one of the manifestations of SARS-CoV-2 infection, which features specific changes in the pharyngoscopic pattern, long fluctuating course and increase in symptoms severity after a physical exercise, which requires long-term therapy with topical agents. A comparative analysis of Tonsilgon N effect on the course of SARS-CoV-2 associated pharyngitis as well as post-COVID syndrome development was carried out in this study. 164 patients with acute pharyngitis associated with SARS-CoV-2 were included in the study. Main group ( n =81) received Tonsilgon N oral drops in addition to the standard treatment regimens for pharyngitis and control group ( n =83) received standard regimen alone. Treatment regimen lasted for 21 days for both groups, followed by follow up examination in 12 weeks for assessment of post-COVID syndrome development. Patients taking Tonsilgon N showed a statistically significant symptoms improvement in throat pain relief ( p =0.002) and throat discomfort ( p =0.004), however, no statistically significant difference in two groups were observed in inflammation severity based on pharyngoscopy examination ( p =0.558). Addition of Tolzilgon N to the regimen reduced occurrence of secondary bacterial infections and therefore use of antibiotics more than 2.8 times ( p <0.001). Compared with the control group long term topical therapy with Tolzilgon N showed no increase in occurrence of side effects such as allergic reactions ( p =0.311) as well as subjective burning sensations in the throat ( p =0.849). In main group occurrence of post-COVID syndrome was observed 3.3 times less than in the control group (7.2% vs 25.9%, p =0.001). These results give us the ground for indication of Tonsilgon N use in the treatment of viral pharyngitis associated with SARS-CoV 2 infection and in prevention of post-COVID syndrome.

The activity of the antimetabolic drug Riamilovir (Triazavirin®) was studied on a model of SARS-CoV-2 infection on Syrian hamsters. Infectious process was caused by the intranasal administration of the virus accumulated in the Vero-B culture with a concentration of 4.25×104 TCID50, in a volume of 26 µl/hamster. The effects of the drug at a dose of 20 mg/kg intraperitoneally daily in the midst of the infectious process were traced to accelerate the clearance of the virus in the lungs, prevent body weight loss and the severity of pulmonary edema, as well as preserve the mass of the spleen. The protective effects of Riamilovir on the structure of the lungs and brain are shown, it is suggested that the drug has the ability to penetrate the blood-brain barrier. It was concluded that Riamilovir has antiviral activity against SARS-CoV-2.

Background. Currently, the COVID-19 pandemic in the world and in Russia remains the main event. In this regard, the study of the manifestations of the epidemic process of the new coronavirus infection COVID-19 and the patterns of its development are an urgent area of research. In the fight against this viral disease, an important role is assigned to the study of the development of population immunity to the SARSCoV-2 virus, which will make it possible to assess the dynamics of seroprevalence and the formation of post-infectious humoral immunity, forecasting the development of the epidemiological situation, elucidating the characteristics of the epidemic process, and will also contribute to planning activities for specific and non-specific prevention of the disease.The aim: to determine the dynamics of population immunity to SARS-CoV-2 among the population of the Irkutsk region during the COVID-19 pandemic.Materials and methods. As a part of the Rospotrebnadzor project of assessing population immunity to SARS-CoV-2 in the population of the Russian Federation, the research has being conducted among the population of the Irkutsk region in the periods from June 23, 2020 to July 19, 2020 (Stage 1), from September 16, 2020 to September 25, 2020 (Stage 2), from December 7, 2020 to December 18, 2020 (Stage 3) and from March 8, 2021 to March 14, 2021(Stage 4), taking into account the reacted one recommended by the WHO. The content of antibodies to SARS-CoV-2 was determined by ELISA using a set of tests for human serum or plasma for specific immunoglobulins of class G to the proteins of the SARS-CoV-2 coronavirus.The results. The research of the humoral immunity of volunteers shows that during the period of an epidemic rise in the incidence of COVID-19 in the Irkutsk region, a low level of seroprevalence was formed (Stage 1 – 5.8 ± 0.5 %, Stage 2 – 12.1 ± 0.7 %), and in conditions of a long-term maximum increase in the incidence rate – 25.9 ± 1.0 % (Stage 3) and 46.2 ± 1.2 % (Stage 4). A significant proportion (Stage 1 – 82.2 ± 3.2 %, Stage 2 – 86.1 ± 2.3 %) of asymptomatic forms of infection characterizes the high intensity of the latently developing epidemic process in the first two stages. High levels of IgG in reconvalescents of COVID-19 persisted for an average of 3 to 5 months.Conclusion. The results of assessing the population immunity to the SARS-CoV-2 virus in the population of the Irkutsk region indicate that the seroprevalence level at Stage 4 of the research was 46.2 %. After the disease, on average, 49.5 % of persons did not detect antibodies. The results obtained should be taken into account when organizing preventive measures, including vaccination, and predicting morbidity.

Aim. To determine the level of SARS-CoV-2 seroprevalence among the Novosibirsk Region population against the background of the COVID-19 pandemic. Material and methods. The work was carried out in 2 phases: 1) a cross-sectional cohort study performed 28.06– 15.07.2020; 2) longitudinal cohort 3-stage seromonitoring: 1st stage 28.06–15.07.2020; 2nd 14.09–04.10.2020; 3rd 10–30.12.2020 The work was carried out according to a unified methodology developed by Rospotrebnadzor with the participation of St-Petersburg Pasteur Institute, taking into account the recommendations of the WHO. IgG antibodies to the SARS-CoV-2 nucleocapsid protein were detected by ELISA using a kit of reagents produced by the SRCMSB (Obolensk) according to the manufacturer’s instructions. Statistical analysis was performed using Microsoft Excel 2010 and other programs. Results. The seroprevalence in the region’s population was 9.1% (95% CI 8.0–10.2): maximum in children 14–17 years old (17.6%, 95% CI 12.3–23.9) and persons over 75 years (14.8%, 95% CI 11.4–18.8), minimum among persons 30–39 years old (4.9%, 95% CI 3.0–8.0). Increased rate was noted among the unemployed (15.4%, 95% CI 9.9–17.1) and other individuals (13.0%, 95% CI 8.6–18.5). Seroprevalence was 33.3% (95% CI 16.3–59.0) in COVID-19 convalescents and 19.0% (95% CI 13.9-25.0) in contact persons. More than 94.7% (95% CI 91.2–97.2) of seropositive individuals were asymptomatic. During the serological monitoring, seroprevalence increased from 7.4% (95% CI 6.2–8.9) at 1st stage 1 to 12.4% (95% CI 10.6–14.3) at 2nd , and 31% (95% CI 28.8–33.3) at 3rd stage. Conclusion. SARS-CoV-2 herd immunity has not reached the threshold level, this does not exclude exacerbation of the epidemic process.

Introduction. Since the outbreak of the COVID-19 pandemic caused by SARS-CoV-2 novel coronavirus, the international community has been concerned about the emergence of mutations altering some biological properties of the pathogen like increasing its infectivity or virulence. Particularly, since the end of 2020, several variants of concern have been identified around the world, including Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2). However, the existing mechanism of detecting important mutations are not always effective enough, since only a relatively small part of all pathogen samples can be examined by whole genome sequencing due to its high cost. Material and methods. In this study, we have designed special primer panel and used it for targeted highthroughput sequencing of several significant S-gene (spike) regions of SARS-CoV-2. The Illumina platform averaged approximately 50,000 paired-end reads with a length of ≥150 bp per sample. This method was used to examine 579 random samples obtained from COVID-19 patients in Moscow and the Moscow region from February to June 2021. Results. This study demonstrated the dynamics of distribution of several SARS-CoV-2 strains and its some single mutations. It was found that the Delta strain appeared in the region in May 2021, and became prevalent in June, partially displacing other strains. Discussion. The obtained results provide an opportunity to assign the viral samples to one of the strains, including the previously mentioned in time- and cost-effective manner. The approach can be used for standardization of the procedure of searching for mutations in individual regions of the SARS-CoV-2 genome. It allows to get a more detailed data about the epidemiological situation in a region.

The capability to detect Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and identify immune responses among the population is crucial for managing the outbreak of the COVID-19 pandemic. Although PCR-based nucleic acid detection techniques are utilized to detect viral infection in people, alternative tests capable of distinguishing between exposure and infection are urgently needed beyond this restricted window of detectable viral replication. Antibodies are produced in human sera within a few days after viral infection, providing longer period for performing tests to acquire reliable database. Herewith, we provide the results of our in-house developed ELISA (Enzyme-Linked Immunosorbent Assay) that displays all of the properties necessary for high-throughput of human sera sample analysis. This test does not involve the handling of live viruses, although it detects a variety of antibody types in serum and plasma of human after exposure to the virus. For in-house development of the kit, the nucleocapsid (N) gene of SARS-CoV-2 virus was cloned in the prokaryotic expression vector pGEX-6P-1, and purified N protein was used to detect IgG antibodies in human sera samples. In total 76 human serum samples that were collected before novel coronavirus registry in Mongolia in March 2020, as well as 200 serum samples from patients who had been infected by SARS-CoV-2 virus, were used. Among 200 serum samples, 188 were positive and 12 were false negative, while in non-infected cases 69 were negative and 7 were false positive, suggesting 94 per cent sensitivity and 90.7 per cent specificity of the kit, with p-values of 0.02.

At the beginning of pandemic of SARS-CoV-2 children were thought to go through COVID 19 in a definitely milder way than adults, in most cases even asymptomatically. However, even though the period of infection in pediatric patients is benign, SARS-CoV-2 found a way to take its toll on children’s health. Here comes PIMS-TS: Paediatric inflammatory multisystem syndrome - temporally associated with SARS-CoV-2 (PIMS-TS) [ICD-10: U 10.9]. Since the global pandemic of COVID-19 is still on the go, for over a year now, SARS-CoV-2 tends to constantly mutate and affect children at increasingly young age either by oligosymptomatic respiratory viral infection, or more distant SARS-CoV-2-related medical condition- PIMS-TS. Paediatric inflammatory multisystem syndrome - temporally associated with SARS-CoV-2 (PIMS-TS), or Multisystem inflammatory syndrome in children (MIS-C) as it’s also called, is a rare systemic disease manifested by persistent fever and extreme inflammatory reaction following exposure to SARS-CoV-2, 2-4 weeks before the symptoms occur. It’s a brand new medical condition, described for the first time in May 2020. PIMS-TS affects 1 out of 1000 children infected with SARS-CoV-2 and can lead to very dangerous cardiological complications such as acute pancarditis, shock or aneurysms of coronary arteries. Efficient treatment performed in the accurate time and hospitalization in ICU allow to overcome PIMS-TS in the prevalent number of patients and get better in a few days. Mortality of PIMS-TS ranges from 1,5% to 2% of all cases.

Введение. В настоящее время новой коронавирусной инфекцией (КВИ) SARS-CoV-2, ставшей причиной развития пандемии COVID-19, по данным ВОЗ инфицированы более 185 млн человек. В отечественной и зарубежной литературе активно дискутируется вопрос повышения риска развития тромбоэмболии лёгочной артерии (ТЭЛА) и ассоциированного тяжелого течения заболевания у лиц с абдоминальным ожирением (АО). Цель исследования. Определить клинико-лабораторные особенности ТЭЛА у пациентов с абдоминальным ожирением, инфицированных SARS-CoV-2. Материал и методы. Проведен анализ 11 056 медицинских карт стационарных пациентов, проходивших лечение в инфекционных отделениях для пациентов с COVID-19 учреждения здравоохранения «4-я городская клиническая больница им. Н.Е. Савченко» г.Минска в период с 1 апреля 2020 года по 31 мая 2021 года. АО у лиц, включенных в ретроспективный анализ, определялось согласно критериям ВОЗ при индексе массы тела большем либо равном 30 кг/м2, окружности талии более 94 см у мужчин и 80 см у женщин, соответственно. Для определения клинико-лабораторных особенностей ТЭЛА, а также влияния АО на тяжесть течения данного осложнения были разработаны критерии включения/невключения/исключения и проведена выборка медицинских карт пациентов с COVID-19 (n=33), у которых диагноз ТЭЛА был верифицирован при проведении компьютерной томографической ангиографии органов грудной клетки. В исследуемых группах были проанализированы клинико-инструментальные показатели и лабораторные характеристики на момент поступления в стационар и при развитии ТЭЛА. Результаты. По результатам ретроспективного анализа 11 056 медицинских карт удельный вес пациентов, у которых в структуре заключительного диагноза присутствовала ТЭЛА, составил 3,68% (n=407), среди них АО наблюдалось у 22,11% (n=90) лиц. Доля лиц с нарушением жирового обмена среди включенных в анализ составила 11,38% (n=1259). ТЭЛА развилась у 90 пациентов с КВИ и АО (0,81 %) и 317 человек без АО (2,87%). Удельный вес пациентов с ТЭЛА (n=90) в группе КВИ и АО (n=1259) составил 7,15%; среди лиц с КВИ без АО (n=9797) – 3,24% (n=317). В сформированной группе с АО уровни С-реактивного белка (СРБ) и фибриногена при госпитализации были выше, чем в группе пациентов без АО: 116,64 (80,38-134,08) мг/л против 30,21 (15,11-57,21) мг/л (U= 36,04; р

In a pandemic, a special group is made up of patients with cardiovascular pathology. Cardiovascular diseases are largely associated with an increase in mortality and an increased risk of complications in patients infected with the SARS-CoV-2 virus. This determines the importance of risk stratification, the choice of optimal personalized therapy and the study of the long-term prognosis of myocardial infarction against the background of infection caused by SARS-CoV-2. Despite the rapidly growing attention to this issue, the mechanisms of the relationship between cardiovascular disease and COVID-19 are not completely clear. We conducted a systematic review to summarize important aspects of COVID-19 for cardiologists. The authors discuss both well-studied factors of the infectious process leading to acute myocardial damage and decompensation of existing chronic cardiac diseases, and new, fundamental, determining prognosis and treatment. Information on the topic was used from publications based on the PubMed, Google Scholar and eLibrary.ru databases. This work was carried out within the framework of a research grant № 67573613 of Pfizer.

On account of the COVID-19 pandemic, the global pharmaceutical industry has achieved impressive results in the development and introduction of various types of vaccines causing the formation of acquired immunity against the SARS-CoV-2 coronavirus into clinical practice. However, none of them currently show the declared one hundred percent guarantee of protection. In the case of the COVID-19 disease, patients with concomitant pathologies are the most vulnerable to the occurrence of severe complications. The aerosol route of transmission of SARS-CoV-2 contributes to the emergence of outbreaks of the new coronavirus infection in crowded places and closed rooms with poor ventilation. In this regard, an urgent problem is the search for drugs with local antiviral activity, which, together with restrictive measures and mask wearing policy, can potentially reduce the likelihood of contracting coronavirus. In this experimental in vitro study on Vero CCL81 cell culture (ATCC), the local antiviral activity of the drug Thymogen® spray against the SARS-CoV-2 virus was studied in comparison with the antiseptic Miramistin® solution. As a result of the experiment, no toxic effects on Vero cells were detected in the drugs in the studied concentrations. In a series of experiments, Thymogen® spray showed local antiviral activity against SARS-CoV-2 when the virus titer was 5,2 lg TCID50. Therefore, the drug Thymogen® dosed nasal spray has high potential as a topical drug for prevention and treatment of COVID-19 disease, which requires additional confirmation in relevant clinical studies.

Introduction. The COVID-19 pandemic has stimulated the search for drugs with specific antiviral activity against the new pathogenic strain of the SARS-CoV-2 coronavirus. First of all, scientific search was aimed at studying drugs with already proven efficacy against influenza and ARVI. The aim of this work was to study the antiviral activity of Cytovir®-3 in vitro in relation to the cytopathogenic effect of the SARS-CoV-2 virus. Material and methods. The antiviral activity of the drug Cytovir®-3 against the SARS-CoV-2 virus was studied in experimental models in vitro on Vero CCL81 cell culture (ATCC). The maximum tolerated concentration and the 50% cytotoxic dose were determined using a quantitative microculture tetrazolium test assay to calculate the working range of the concentrations of the test drug. Results and discussion. As a result of the study, it was shown that the greatest activity of the drug was manifested when it was added to the cells 24 hours before and 1 hour and 24 hours after viral infection, the inhibition level reached 53% (>IC50) at the drug concentrations of 105, 55, and 85 µg/ml, respectively. Cytovir®-3 suppressed the viral activity of SARS-CoV-2 in the dose range from 10 µg/ml to 105 µg/ml under the indicated infection conditions. It was found that the drug did not exhibit cytotoxic effects on the Vero cell culture in the range of antiviral doses. Conclusion. The antiviral activity of Cytovir®-3 against the SARS-CoV-2 virus has been proven due to the achievement of IC50, which is below the maximum tolerated dose of 149 µg/ml.

Purpose. Determination of the SARS-CoV-2 population humoral immunity among the population of the Krasnoyarsk Territory during the COVID-19 epidemic.Materials and methods. The study was carried out as a part of project for assessing population immunity to SARS-CoV-2 among the population of Russian Federation using unified methodology developed by Rospotrebnadzor, with the participation of the Research Institute for Epidemiology and Microbiology named by Pasteur, and taking into account the recommendations of the WHO. The work involved 2907 volunteers, selected by the online survey and randomization by age and territory. All volunteers were divided into 7 age groups: 1–17, 18–29, 30–39, 40–49, 50–59, 60–69, 70 and older (70+), including a total 246–449 people. Population immunity testing was carried out during the formation of groups (1st stage), and then twice more, with the interval of 6–8 weeks. Serum was obtained from venous blood samples obtained from volunteers, in which antibodies to the SARS-CoV-2 nucleocapsid were determined by the enzyme immunoassay. The results were analyzed by methods of nonparametric statistics: median, interquartile range, rank correlation coefficient were calculated in the Excel statistical package. The confidence interval to seroprevalence indicators (95% CI) was calculated using the WinPepi statistical package (version 11.65). The statistical significance of the differences was assessed with a probability level of p ≤ 0.05.Results. The seroprevalence of the population of the Krasnoyarsk Territory during the 5-month period of seromonitoring had increased 3.3 times from 12.8% (95% CI 11.3–14.4) to 41.7% (95% CI 39.4–4.0) , while the grouping by age had not revealed any peculiarities throughout the study. The trend towards a decrease in the incidence was formed on the 6th week of 2021. The seroprevalence of convalescents after COVID-19 during the initial testing was 61.5% (95% CI 40,6–79.8), among those who were in contact with patients with COVID-19 or convalescents –23.8% (95% CI 13.9–36.2) . Among the volunteers, 347 seropositive persons were identified, 324 of which were observed asymptomatic course.Conclusion. The structure of the population humoral immunity to SARS-CoV-2 of he population of the Krasnoyarsk Territory has been investigated. It was found that an increase in seroprevalence to 41.7% (95% CI 39.4–4.0) was accompanied by a decrease in morbidity.

Introduction: Convalescent COVID-19 patients have various signs of central nervous system damage, including those directly associated with SARS-CoV-2. Hence, studies of SARS-COV-2 related morphological changes in neocortex are particularly relevant for understanding the mechanisms of their formation and development of approaches to preclinical evaluation of the effectiveness of antiviral drugs. The purpose of the research is a longitudinal study of the ultrastructural alterations in Syrian hamsters neocortex after experimental SARS-CoV-2 infection., Materials and Methods: Male Syrian hamsters weighing 80100 g, aged 4 to 6 weeks, were infected with 26 l SARS-CoV-2 intranasally with 4104 TCD50/ml of viral particles. The animals were euthanized on days 3, 7 or 28 post-infection, the brain was extracted with the cortex excision. The material analysis was performed using transmission electron microscopy., Results and Discussion: On day 3 post-infection, the number of moderately hyperchromic neurons in neocortex increased, while by the day 7 the number of apoptotic cells significantly increased. Simultaneously, an increased signs of neuronophagy and representation of atypical glia were observed. Increased number of altered oligodendrocytes was observed on day 28 post-infection. Viral invasion was accompanied by changes in neocortical cells since day 3 post-infection, such as transformation of their nucleus, the rough endoplasmic reticulum and the Golgi vesicles as well as microvascular spasm with perivascular edema., Conclusion: As a result of electron microscopic study, the ultrastructural alterations in neocortex were described in an experimental model of SARS-CoV-2 infection. The findings can be used to identify the mechanisms of infection pathogenesis and to search for the new directions in development of medicines.

This study provides an overview of scientific results on the feasibility of using type III interferons against SARS-CoV-2. We have analyzed data obtained from the PubMed electronic database for the period 2020-2022. The results of our own studies of pharmacological substances based on recombinant IFN-λ1 and its pegylated form are also presented. Completed and ongoing investigations allow us to position IFN-λ as an effective therapeutic agent against SARS-CoV-2.

Introduction: COVID-19 is an infection caused by the new SARS-CoV-2 virus. In pregnant women with COVID-19, compared to non-pregnant women, there is an increased risk of a severe course of the infection. Pregnant women are more often hospitalized in the Intensive Care Unit and require mechanical ventilation. In the course of COVID-19 infection, pregnant women have a greater risk of miscarriage, premature birth or having a baby with low birth weight, compared to their healthy pregnancy peers. The aim of the study: To present, based on the available literature, the principles of management of a pregnant woman infected with SARS-CoV-2 virus. State of knowledge: The evidence of infection is the detection of the virus in the clinical specimen confirmed by PCR. Chest computer tomography can be useful in diagnosis, especially when the PCR test result is negative. Particular attention should be paid to pharmacological treatment, which should be both effective and safe for the fetus. Certain antiviral and anti-inflammatory drugs as well as anticoagulants drugs are used in COVID-19 therapy. Oxygen and fluid therapy is also important. The condition of the fetus should be monitored regularly. It is recommended to measure the fetal heart rate, perform cardiotocography, pregnancy ultrasound and assess the volume of amniotic fluid. The decision about the time and method of delivery should be made individually on the basis of obstetric indications and the maternal-fetal condition. Summary: The therapy of a pregnant patient infected with SARS-CoV-2 should be adjusted individually depending on the woman's health condition. In therapeutic interventions, the welfare of both the mother and the fetus should be taken into account.