Search

Introduction: For four years, SARS-CoV-2, the etiological agent of COVID-19, has been circulating among humans. By the end of the second year, an absence of immunologically naive individuals was observed, attributable to extensive immunization efforts and natural viral exposure. This study focuses on delineating the molecular and biological patterns that facilitate the persistence of SARS-CoV-2, thereby informing predictions on the epidemiological trajectory of COVID-19 toward refining pandemic countermeasures. The aim of this study was to describe the molecular biological patterns identified that contribute to the persistence of the virus in the human population., Materials and Methods: For over three years since the beginning of the COVID-19 pandemic, molecular genetic monitoring of SARS-CoV-2 has been conducted, which included the collection of nasopharyngeal swabs from infected individuals, assessment of viral load, and subsequent whole-genome sequencing., Results: We discerned dominant genetic lineages correlated with rising disease incidence. We scrutinized amino acid substitutions across SARS-CoV-2 proteins and quantified viral loads in swab samples from patients with emerging COVID-19 variants. Our findings suggest a model of viral persistence characterized by 1) periodic serotype shifts causing substantial diminutions in serum virus-neutralizing activity (> 10-fold), 2) serotype-specific accrual of point mutations in the receptor-binding domain (RBD) to modestly circumvent neutralizing antibodies and enhance receptor affinity, and 3) a gradually increasing amount of virus being shed in mucosal surfaces within a single serotype., Conclusion: This model aptly accounts for the dynamics of COVID-19 incidence in Moscow. For a comprehensive understanding of these dynamics, acquiring population-level data on immune tension and antibody neutralization relative to genetic lineage compositions is essential.

The aim of the work was to evaluate the ability of monoclonal antibodies to inhibit the interaction of the receptor binding domain (RBD) in S protein of SARS-CoV-2 virus variants, Wuhan-Hu-1 and BQ 1.1, with the angiotensin-converting receptor 2 (ACE2). Materials and methods. In this study, recombinant RBDs of Wuhan-Hu-1 and BQ 1.1 variants were used as antigens. For mouse monoclonal antibody (mMCA) production, hybridomas were cultured in vivo in BALB/c mice. mMCAs were isolated from ascitic fluid by ammonium sulfate treatment followed by purification through column affinity chromatography with Protein G Sepharose sorbent. The specific activity of mMCAs was assessed by immunoblot with recombinant RBD of Wuhan-Hu-1 variant. To identify the most promising mMCA, the neutralizing activity of mMCA was evaluated by enzyme-linked immunosorbent assay (ELISA) via immobilizing RBD on the surface of a microplate and using ACE2 in the form of horseradish peroxidase conjugate. Recombinant antigens were produced in ExpiCHO-S cell line (Gibco, USA). Results and discussion. Three mMCAs have been described as a result of the study: 5C3, 3F11, 1E6. All antibodies belong to immunoglobulins of subclass G and specifically interact with the RBD in S protein of SARS-CoV-2 virus. The most effective inhibition of the interaction between ACE2 and the RBD of BQ 1.1 strain was observed for murine MCA 3F11 (65 %), while the interaction with the RBD of Wuhan-Hu-1 strain was inhibited by mMCA 5C3 (91 %). The identified characteristics allow for considering the antibodies as potential candidates for the development of antibody-based therapeutics, thus expanding the possibilities of therapy for SARS-CoV-2 virus infection.

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

Introduction. For four years, SARS-CoV-2, the etiological agent of COVID-19, has been circulating among humans. By the end of the second year, an absence of immunologically naive individuals was observed, attributable to extensive immunization efforts and natural viral exposure. This study focuses on delineating the molecular and biological patterns that facilitate the persistence of SARS-CoV-2, thereby informing predictions on the epidemiological trajectory of COVID-19 toward refining pandemic countermeasures. The aim of this study was to describe the molecular biological patterns identified that contribute to the persistence of the virus in the human population. Materials and methods. For over three years since the beginning of the COVID-19 pandemic, molecular genetic monitoring of SARS-CoV-2 has been conducted, which included the collection of nasopharyngeal swabs from infected individuals, assessment of viral load, and subsequent whole-genome sequencing. Results. We discerned dominant genetic lineages correlated with rising disease incidence. We scrutinized amino acid substitutions across SARS-CoV-2 proteins and quantified viral loads in swab samples from patients with emerging COVID-19 variants. Our findings suggest a model of viral persistence characterized by 1) periodic serotype shifts causing substantial diminutions in serum virus-neutralizing activity ( 10-fold), 2) serotype-specific accrual of point mutations in the receptor-binding domain (RBD) to modestly circumvent neutralizing antibodies and enhance receptor affinity, and 3) a gradually increasing amount of virus being shed in mucosal surfaces within a single serotype. Conclusion. This model aptly accounts for the dynamics of COVID-19 incidence in Moscow. For a comprehensive understanding of these dynamics, acquiring population-level data on immune tension and antibody neutralization relative to genetic lineage compositions is essential.

Introduction. Animal models for SARS-CoV-2 infection, reproducing the clinical features of COVID-19 in humans, are important tools for studying the pathogenesis of the disease, transmission of the pathogen and are indispensable for testing antiviral drugs and vaccines. The aim of the study was to assess the virulence and tissue tropism for golden Syrian hamsters of SARS-CoV-2 strains belonging to different epidemiologically significant variants: Wuhan-like, Delta, Omicron BA.1.1 and Omicron BA.5.2. Materials and methods. Hamsters were intranasally infected with different SARS-CoV-2 strains. Virulence and tissue tropism of SARS-CoV-2 strains were assessed by comparing the dynamics of weight, viral load in organs and histopathological changes in lungs in infected and uninfected animals. Results. The Wuhan-like Dubrovka strain had the greatest virulence for hamsters, which was manifested by the development of severe pneumonia and a delay in weight gain by 14.6%, high virus content in the lungs, nasal passages and brain — 6.2, 5,9 and 3.7 lg TCID50/ml of homogenate, respectively. Presumably, it was the infection of the Wuhan-like virus of the central nervous system that negatively affected the weight and general condition of the animals. When hamsters were infected with viruses belonging to the Delta and Omicron variants, the observed minor weight loss in animals was uninformative, so indicators such as lung histopathology, viral load in the lungs, nasal passages, heart and other organs played a decisive role in assessing the virus pathogenicity. A score assessment of lung histopathology was of particular value in assessing the severity of pneumonia, since it reduced subjectivity in evaluating the results of histological examination and provided a semi-quantitative assessment of the pathological process. Conclusion. Despite the revealed lower virulence for hamsters of viruses belonging to the Delta and Omicron variants compared to the ancestral Wuhan virus, this animal model for COVID-19 retains its value for conducting preclinical trials of antiviral drugs.

Introduction. In response to the COVID-19 pandemic in the Russian Federation, comprehensive response measures were taken. One of these measures was the development of a viral genome aggregation platform (VGARus) to monitor virus variability. The aim of this paper is to describe the role of the VGARus platform in tracking genetic variation in SARS-CoV-2. Materials and methods. VGARus utilizes sequencing data and bioinformatics tools to monitor genetic variations in SARS-CoV-2. The viral genomes were aligned using NextClade, which also translated them into amino acids and identified mutations. The viral variability over time was analyzed by counting the number of amino acid changes compared to the reference sequence. Results. The analysis of data within VGARus enabled the identification of new virus variants, contributing to improved diagnostic tests and vaccine development. The platform allowed for the prediction of epidemiologic trends, facilitating a rapid response to changes in the epidemiologic situation. For example, using VGARus, an increase in COVID-19 incidence was accurately predicted in the summer of 2022 and early 2023, which were associated with the emergence of Omicron subvariants BA.5 and XBB. Data from the platform helps validate the effectiveness of primers and DNA probes to ensure high diagnostic accuracy and reduce the risk of false negatives. Conclusion. VGARus demonstrates the growing role of genomic surveillance in combating COVID-19 and improving preparedness for future infectious disease outbreaks. The platform is a powerful tool for generating evidence-based solutions to combat a pandemic and mitigate its health, economic and societal impacts. It provides the ability to promptly obtain information on the epidemiologic situation in a particular region of the Russian Federation, use genomic data for phylogenetic analysis, compare the mutational spectrum of SARS-CoV-2 sequences with foreign samples. VGARus data allow for both retrospective analysis and predictive hypotheses. For example, we can clearly see the dynamics of the change of different virus variants: sequences belonging to the Alpha, Beta, Delta, Omicron lineages and many less common ones, clearly form the upsurges of morbidity, the interaction of which is reflected in the epidemiological picture. It is also currently being expanded to monitor other pathogens, increasing its public health relevance.

Aim: To study the clinical and histological profile of lung tissue in patients with persistent pulmonary disease, respiratory symptoms and CT findings after SARS-CoV-2 infection., Materials and Methods: The study included 15 patients (7 females and 8 males) with a mean age of 57.7 years. All patients underwent laboratory tests, chest computed tomography, echocardiography, and pulmonary function tests. Pulmonary tissue and bronchoalveolar lavage samples were obtained by fibrobronchoscopy, transbronchial forceps (2 patients), and lung cryobiopsy (11 patients); open biopsy was performed in 2 patients. Cellular composition, herpesvirus DNA, SARS-CoV-2, Mycobacterium tuberculosis complex, galactomannan optical density index, and bacterial and fungal microflora growth were determined in bronchoalveolar lavage. SARS-CoV-2 was also identified in samples from the nasal mucosa, throat and feces using a polymerase chain reaction., Results: The results showed no true pulmonary fibrosis in patients recovered from SARS-CoV-2 infection with persistent respiratory symptoms, functional impairment, and CT findings after SARS-CoV-2 infection. The observed changes comply with the current and/or resolving infection and inflammatory process., Conclusion: Thus, no true pulmonary fibrosis was found in patients after SARS-CoV-2 infection with persistent respiratory symptoms, functional impairment, and CT findings. The observed changes comply with the current and/or resolving infection and inflammatory process.

The aim of this review was to present the mechanism of infection with severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) and its possible effect on the course of arterial hypertension. Another aim was to evaluate the relationship of the renin-angiotensin-aldosterone system with the pathogenetic stages of infection caused by SARS-CoV-2 virus.

To conduct a study of the quality of life of children who have suffered from multisystem inflammatory syndrome (MIS‐C) associated with SARSCoV‐2 in the post‐rehabilitation period against the background of correction of microecological imbalance.The study involved 49 children aged 2 to 12 years who underwent MIS‐C associated with SARS‐CoV‐2 and received treatment in a hospital (DGKB No. 3 in Novosibirsk), and then underwent rehabilitation on an outpatient basis. The duration of rehabilitation was 7–8 weeks. All children were prescribed a course of additional rehabilitation for 30 days in order to correct microecological imbalance, which included: Biovestin, a dietary supplement in liquid form, containing bifidobacteria of the Bifidobacterium longum MC‐42 strain; the official drug, Kudesan, (active ingredient Coenzyme Q10); and the official drug, Succinic Acid. The assessment of physical, social, educational, emotional and psychological functioning, as well as quality of life as an integrating indicator before and after a comprehensive rehabilitation course using the parental form of the Reds OL Generic Core Scales questionnaire (Russian version) was carried out.After the rehabilitation course, children who underwent MIS‐C associated with SARS‐CoV‐2 showed signs of dysfunction of various organs and systems, which may be the result of an imbalance in the microbial ecosystem and requires mandatory correction. The introduction of a probiotic product and drugs affecting metabolic processes into the rehabilitation course led to a decrease in inflammatory reactions, as well as normalisation of metabolic processes and increased oxygenation, which improved the condition of the children and their quality of life.Federal Research Center for Fundamental and Translational Medicine (FRC FTM), Siberian Branch, Russian Academy of Sciences

In 2019, the COVID-19 pandemic began and changed the world. Coronavirus SARS-CoV-2 has caused widespread illness and death around the world. In this regard, vaccination become the most important tool for creating herd immunity. Our study analyzed the dynamics of pro- and anti-inflammatory cytokines and antibodies to SARS-CoV-2 in the blood serum of young patients before and after vaccination against COVID-19. The study group included 76 young men. Determination of IL-1β, IL-4, IL-6, IL-8, IL-10, IL-17, IFNγ, TNFα and IgM and IgG antibodies to COVID-19 in venous blood sera was carried out twice, by ELISA using the test systems of Vector-Best Company, Novosibirsk. The first blood samples were carried out before vaccination, the second — 1 month after vaccination against COVID-19. The results were processed using STATISTICA 8.0. The vaccinated people were monitored for 6 months after vaccination. Levels of indices before vaccination: IL-1β (5.6 pg/ml (Q₂₅–Q₇₅ = 3.1–14.2); IL-4 (1.02 pg/ml (Q₂₅–Q₇₅ = 0.75–1.28); IL-6 (27.8 pg/ml (Q₂₅–Q₇₅ = 7.1–59.9); IL-8 (29.9 pg/ml (Q₂₅–Q₇₅ = 19.51–32.14); IL-10 (4.47 pg/ ml (Q₂₅–Q₇₅ = 1.84–14.75); IL-17 (7.33 pg/ml (Q₂₅–Q₇₅ = 6.82–8.58); IFNγ (0.7 pg/ml (Q₂₅–Q₇₅ = 0.4–0.9); TNFα (3.9 pg/ml (Q₂₅–Q₇₅ = 2.2–6.4). Levels of indices after vaccination: IL-1β (1.6 pg/ml (Q₂₅–Q₇₅ = 1.4- 2.2); IL-4 (0.84 pg/ml (Q₂₅–Q₇₅ = 0.59–1.12); IL-6 (1.2 pg/ml (Q₂₅–Q₇₅ = 0.6–1.7); IL-8 (10.1 pg/ml (Q₂₅–Q₇₅ = 3.8–28.9); IL-10 (5.84 pg/ml (Q₂₅–Q₇₅ = 1–9.99); IFNγ (0.6 pg /ml (Q₂₅–Q₇₅ = 0.3–0.8); TNFα (0.6 pg/ml (Q₂₅–Q₇₅ = 0.3–1.9). Both before and after vaccination against SARS-CoV-2, different distributions of cytokine levels were identified with a downward trend, but despite this, strong correlations were observed between many of them, which indicates an increase in the tension of the immune system in response to vaccination. When calculating the ratio of pro- and anti-inflammatory cytokines, its two-fold decrease was revealed, which reflects a decrease in the levels of pro-inflammatory cytokines after vaccination. The level of IgG antibodies to COVID-19 exceeded the protective level: more than 14 times in 98% of subjects. Further research into the impact of SARS-CoV-2 vaccination on innate immunity will allow us to reconsider the current vaccination strategy and determine the best approach to preventing COVID-19.

Plasmablasts are a population of short-lived B cells that appear in the circulation shortly after vaccination and during acute infection. Plasmablasts are formed from resting B lymphocytes, from which they differ in their ability to secrete antibodies, making them similar to plasma cells. Plasmablasts are terminally differentiated cells that can form at various nodes and branches of the B cell response. The plasmablast response is an indicator of the success of vaccination and also helps in predicting antibody levels after recovery or vaccination. However, the definition and classification of plasmablasts faces great experimental and theoretical difficulties. The aim of the work was to determine the characteristics of the plasmablast response during acute SARS-CoV-2 infection. The study included patients (n = 28) with a severe form of COVID-19. Blood sampling was carried out once on the 10–18th day from the moment of hospitalization. B cells were isolated by immunomagnetic separation. Cells were phenotyped using flow cytometry. Secretion of IgM and IgG was determined by ELISpot method. B cell subsets were isolated using a cell sorter. Patients with COVID-19 had an approximately fourfold increase in total plasmablast levels compared to healthy donors. An even more pronounced excess over the negative control was observed for RBD-specific plasmablasts. In terms of their composition, plasmablasts were one third IgM⁺ cells. This distribution between B-cell BCR receptor isotypes was consistent with the primary nature of the immune response in COVID-19. Approximately a third of plasmablasts carried the CD138 antigen. CD138 marker is characteristic of the late stage of plasmablast maturation and is also found on plasma cells. The CD27+CD38⁺ population was divided according to the expression of the CD138 antigen. Using the ELISpot method, we have shown that a significant portion of circulating plasmablasts are antibody-secreting cells. Among circulating plasmablasts, both early and late plasmablasts can be distinguished, which are characterized by the absence of a surface BCR, but which carry the CD138 antigen. Determining how plasmablasts relate to other B cell populations is of paramount importance for the development of new treatments for COVID-19 and for the creation of promising vaccines against SARS-CoV-2 infection.

Antigen (AG)-specific T cell activity was compared in two groups of patients: those who underwent COVID-19 in 2021 during the circulation of the SARS-CoV-2 delta virus strain (43 individuals); and those who underwent COVID-19 in 2022 (Omicron strain, 23 individuals). The diagnosis was confirmed by PCR analysis of nasopharyngeal and oropharyngeal swabs. The 23 individuals following COVID-19 caused by SARS-CoV-2 (omicron) were part of a cohort of 41 volunteers who were examined multiple times during 2021–2023: during vaccination, after vaccination, before revaccination, and subsequently after illness (6–8 times in total). Due to this, it was possible to compare the indices of specific humoral and cellular immunity in the same patients 1–2 months before and after breakthrough infection. Detection of AG-specific T cells and assessment of their activity by AG-stimulated IFNγ production was carried out by our own previously developed method (Patent RU № 2780369 C1). For stimulation of memory T effectors in vitro, the same antigens were used to determine the concentration of antibodies against SARS-CoV-2 by ELISA method. A total of about 300 blood samples from healthy subjects and patients after COVID-19 were analyzed. Each sample was tested against 3 SARS-CoV-2 antigens and in 2 stimulation modes. A qualitative assessment algorithm for AG-specific T cell activity has been proposed that can be used to monitor the state of cellular immunity in a population in which SARS-CoV-2 virus continues to circulate and to create insights into what level of T cell activation is sufficient to prevent or reduce the severity of SARS-CoV-2 infection. Unvaccinated COVID-19 (SARS-CoV-2, Delta) survivors lacked AG-specific T cells to RBD SARS-CoV-2, but T cell specificity to full-length S glycoprotein at the same level, qualitatively assessed as low in 52% of the group, persisted for up to six months. In previously unvaccinated COVID-19 vaccinees, this duration of persistence of AG-specific T cells in circulating blood was achieved only after revaccination. Hybrid immunity, which we traced as a result of vaccination after COVID-19 (Delta strain) or as a breakthrough infection (SARS-CoV-2, Omicron), is characterized by the highest indices of memory T cell activity (43–46% of the group — normal activity of AG-specific cells, 30–43% — high activity) to all used antigens and the longest duration of preservation of indices at this level. Further investigation of the level of antiviral immunity after COVID-19 may be important for predicting the outcome of new waves of SARS-CoV-2 infection.

The aim of the work was to study the features of the infectious process in the lungs of animals used as models for assessing SARS-CoV-2 pathogenicity.Materials and methods. The strain of SARS-CoV-2 alpha variant virus was used in the work. The experiments were carried out on linear and transgenic mice, Syrian hamsters, guinea pigs, ferrets and two types of primates: rhesus macaques and green monkey. The pathomorphological examination was performed by optical microscopy of histological lung preparations using a computerized microscope with digital microphotography.Results and discussion. A comparative histological analysis of the lungs in six different types of laboratory animals was carried out when modeling a new coronavirus infection; similar morphometric signs of the severity of the disease caused by the SARS-CoV-2 virus in sensitive animals were determined, and a dose-dependent correlation of pathological changes in lung tissues with intranasal administration of various infectious doses was revealed. The features of pathomorphological changes in six different animal species in the simulation of a new coronavirus infection have been characterized, and their dose-dependent nature determined. The presented research results can be used to select a model animal for the purpose of in-depth study of the pathogenesis of COVID-19 caused by newly isolated coronavirus variants, the dynamics of immune reactions of the body during the development of the disease, as well as in vivo studies of the protective effect of promising therapeutic drugs and vaccines.

Objective: To identify the reasons for unsatisfactory treatment results for acute purulent destructive lung diseases (APDLD) in patients with SARS-CoV-2 Methods: Sixty-five patients with APDLD on the background of SARS-CoV-2 infection were included in the study; 37 (57%) patients (Group 1) with APDLD were treated in a Tashkent Specialized Clinic for Infectious Diseases, and 28 (43%) patients with APDLD (Group 2) were hospitalized in the clinic of the General and Children’s Surgery Department of the Tashkent Medical Academy with a history of a recent SARS-CoV-2 infection. The patients were investigated using clinical, laboratory, and instrumental methods; the results were processed using statistical methods Results: Complete recovery of patients was achieved in 16% of patients of Group 1 and 32% of Group 2 (p>0.05); clinical recovery was shown in 30% and 43% of patients in Groups 1 and 2 respectively (p>0.05). In Group 1 the results of treatment were more frequently disappointing than in Group 2 (54% vs. 25%, p=0.036), of which 19% were fatal in Group 1 and 11% in Group 2 (p>0.05). For the fatal outcome, the most dangerous was the early period after hospitalization. Morphological changes in the lungs of deceased patients included homogeneous fibrin deposits, which were combined with pronounced interstitial edema and capillary microthrombi around purulent foci. Conclusion: Traditional clinical and laboratory methods for assessing the severity of the condition of patients of both groups during and after SARSCoV-2 infection do not reflect the complete objective picture of the disease, as an accurate picture can only be obtained by applying the criteria for septic complications. Traditional treatment for APDLD is acceptable for patients of Group II. In patients of Group I with a severe, complicated, and progressive course, many methods of conventional therapy proved to be ineffective.

Background. Studying the characteristics of the course of coronavirus infection caused by SARS-CoV-2 remains relevant due to the high mutagenicity of the virus and the prevalence of the disease in the world. The search for new drugs to eliminate clinical manifestations of COVID-19, as well as against its agent, is essential. During the pandemic caused by SARS-CoV-2, dexamethasone was recognized as the only effective anti-inflammatory drug for the treatment of patients with severe form of the disease, but its use leads to a large number of side effects.The aim. To study the therapeutic effect of the drug Molixan in the treatment of coronavirus infection in model animals – Syrian hamsters.Methods. To assess the effectiveness of the drug Molixan, we carried out a visual assessment of the condition of the lungs using light microscopy and the morphometry of the lung tissue of experimentally infected Syrian hamsters on the day 6 after infection under different Molixan treatment regimens and during dexamethasone therapy. The test drug was administered using three different doses (22.2 mg/kg, 44.4 mg/kg and 88.8 mg/kg, which are equivalent to doses of 3 mg/kg, 6 mg/kg and 12 mg/kg of human body weight) once daily or dividing the dose into two within 12 h interval in case of multiple (5 days) intramuscular administration. Dexamethasone (comparison drug) was administered at a dose of 20 mg/kg once daily for 5 days.Results. The studies showed statistically significant effectiveness of using Molixan at a dose of 44.4 mg/kg, divided into two doses, during 5 days. When compared with untreated hamsters, this treatment regimen reduces the degree of generalization and severity of the inflammatory process in the lungs; and the pathomorphological picture is similar to that observed during treatment with Dexamethasone.Conclusion. The studied drug Molixan is effective as an anti-inflammatory drug in the treatment of the disease caused by SARS-CoV-2.

Introduction. The COVID-19 pandemic caused by SARS-CoV-2 has created serious health problems worldwide. The most effective way to prevent the occurrence of new epidemic outbreaks is vaccination. One of the modern and effective approaches to vaccine development is the use of virus-like particles (VLPs). The aim of the study is to develop a technology for production of VLP based on recombinant SARS-CoV-2 proteins (E, M, N and S) in insect cells. Materials and methods. Synthetic genes encoding coronavirus proteins E, M, N and S were used. VLP with various surface proteins of strains similar to the Wuhan virus, Delta, Alpha and Omicron were developed and cloned into the pFastBac plasmid. The proteins were synthesized in the baculovirus expression system and assembled into VLP in the portable Trichoplusia ni cell. The presence of insertion in the baculovirus genome was determined by PCR. ELISA and immunoblotting were used to study the antigenic activity of VLP. VLP purification was performed by ultracentrifugation using 20% sucrose. Morphology was assessed using electron microscopy and dynamic light scattering. Results. VLPs consisting of recombinant SARS-CoV-2 proteins (S, M, E and N) were obtained and characterized. The specific binding of antigenic determinants in synthesized VLPs with antibodies to SARS-CoV-2 proteins has been demonstrated. The immunogenic properties of VLPs have been studied. Conclusion. The production and purification of recombinant VLPs consisting of full-length SARS-CoV-2 proteins with a universal set of surface antigens have been developed and optimized. Self-assembling particles that mimic the coronavirus virion induce a specific immune response against SARS-CoV-2.

Many viruses, including SARS-CoV-2, the coronavirus responsible for the COVID-19 pandemic, enter host cells through a process of cell-viral membrane fusion that is activated by proteolytic enzymes. Typically, these enzymes are host cell proteases. Identifying the proteases that activate the virus is not a simple task but is important for the development of new antiviral drugs. In this study, we developed a bioinformatics method for identifying proteases that can cleave viral envelope glycoproteins. The proposed approach involves the use of predictive models for the substrate specificity of human proteases and the application of a structural analysis method for predicting the vulnerability of protein regions to proteolysis based on their 3D structures. Specificity models were constructed for 169 human proteases using information on their known substrates. A previously developed method for structural analysis of potential proteolysis sites was applied in parallel with specificity models. Validation of the proposed approach was performed on the SARS-CoV-2 spike protein, whose proteolysis sites have been well studied.

Глобальное распространение острого респираторного синдрома SARS-CoV-2, вызывавшего COVID-19, остается чрезвычайной ситуацией в области общественного здоровья. Пандемия привела к более 563312528 случаям инфицирования, поставив под угрозу здоровье и повысив риск потери рабочего места и доходов многих людей по всему миру. Статья посвящена расчетно-графическому анализу эффектов (шоков), произошедших в сферах человеческой деятельности под влиянием синдрома SARS-CoV-2 и вспышки новых штаммов COVID-19, моделированию причиненного социально-экономического ущерба и обоснованию прогнозных трендов социально-экономического состояния общества. Достижение данной цели предполагает решение задачи анализа состояния случаев заражения, смертности и выздоровления населения и обоснования прогнозных сценариев тенденции социально-экономических показателей вследствие появления новых штаммов COVID-19. Методической основой работы явилось применение экономико-статического метода и таблично-графического подхода к количественной оценке эмпирических данных. Предложенная модель количественной оценки последствия воздействия инфекции COVID-2019 позволила выявить факторы снижения деловой активности, социально-экономической стагнации и рецессии мировой экономики. Меры, которые были применены против пандемии, усугубили кризис, существовавший до 2019 г. с беспрецедентными социально-экономическими потрясениями, ростом уровня бедности в мире с 17,1 % до 25,9 % и прогнозируемым ущербом в размере более 1976,80 трлн руб. для мировой экономики, и привели к сокращению скорости восстановления социально-экономического благосостояния с 11,8 до 6,7 месяцев. Отмечено, что когда доля активных инфицированных превысит 1 %, система здравоохранения столкнется с серьезными проблемами, а когда достигнет 10 % — возникнет дисфункция социально-экономических компонентов инфраструктур мировой экономики с макроэкономическими шоками, которые сопровождаются тенденцией снижения мирового ВВП на 2,4 % на перспективу по сравнению с 2021–2022 гг. и на 4 % в 2023 г., что обострит имеющиеся социально-экономические противоречия, рост безработицы, инфляции и приведет к падению уровня реального дохода населения. .

The analysis of existing information about invasion of COVID-19 in Russia shows that that one of leading reason of existing of new rises of covid-19 morbidity is distribution of new genovariants of SARS-CoV-2 virus. The omicron genovariant of SARS-CoV-2 virus was a dominant agent of fifth and subsequent rises of COVID-19 morbidity in Russia. The aim of this work – the estimation of sublines of omicron genovariant of SARS-CoV-2 virus as potential dominant agents of new rises of COVID-19 morbidity in Russia. The source base of the study. Data published in Russian and English-language scientific publications available via the Internet (RSCI, PubMed, Google Scholar). The research method is analytical. Results. The basic properties of omicron genovariant of SARS-CoV-2 virus, epidemical characteristics of the rises of COVID-19 morbidity in Russia, caused by new sublines of omicron variant, estimation ofsublines of omicron genovariant as potential dominant agent of new rises of COVID-19 morbidity in Russia are viewed. It is shown that basic direction of SARS-CoV-2 virus evolution is existing of sublines of omicron genovariant, which are characterized by increased transmissivity but with less severity of the disease caused compared to previously circulated variants of COVID-19agent. The main distinguishing feature of the new subvariants («Kraken», «Czerber», «Centaur», «Arktur», «Pirola») are multiple amino acid exchanges in structural glycoprotein S. The maximum level of variability of this structural protein compared to the original variant of SARS-CoV-2 virus is marked for Pirola subvariant. Onle Kraken subvariant was dominant agent of rise of COVID-19 morbidity in Russia. Conclusion. New rises of COVID-19 morbidity in Russia will not be connected with existing of new subvariants of omicron genovariant, but only with season factor.

Aim. To study the clinical and histological profile of lung tissue in patients with persistent pulmonary disease, respiratory symptoms and CT findings after SARS-CoV-2 infection. Materials and methods. The study included 15 patients (7 females and 8 males) with a mean age of 57.7 years. All patients underwent laboratory tests, chest computed tomography, echocardiography, and pulmonary function tests. Pulmonary tissue and bronchoalveolar lavage samples were obtained by fibrobronchoscopy, transbronchial forceps (2 patients), and lung cryobiopsy (11 patients); open biopsy was performed in 2 patients. Cellular composition, herpesvirus DNA, SARS-CoV-2, Mycobacterium tuberculosis complex, galactomannan optical density index, and bacterial and fungal microflora growth were determined in bronchoalveolar lavage. SARS-CoV-2 was also identified in samples from the nasal mucosa, throat and feces using a polymerase chain reaction. Results. The results showed no true pulmonary fibrosis in patients recovered from SARS-CoV-2 infection with persistent respiratory symptoms, functional impairment, and CT findings after SARS-CoV-2 infection. The observed changes comply with the current and/or resolving infection and inflammatory process. Conclusion. Thus, no true pulmonary fibrosis was found in patients after SARS-CoV-2 infection with persistent respiratory symptoms, functional impairment, and CT findings. The observed changes comply with the current and/or resolving infection and inflammatory process.

The aim of the work was to determine the cytotoxicity and the influence of polycyclic derivatives of the framework series on the replicative properties of the SARS-CoV-2 virus in Vero-E6 cell culture in vitro. Materials and methods. The virus inhibiting effect of 50 adamantane and bicyclo[3.3.1]nonane derivatives with carbocyclic and heterocyclic substituents was investigated. The studies were carried out on Vero-E6 cell culture by assessing the cytopathic effect of the virus. The impact of the compounds on the replicative properties of the SARS-CoV-2 virus was estimated by the decrease in virus titer in the presence of the compounds compared to the control. Based on the virus titer values in the presence of a series of successively decreasing concentrations of the compound, the 50 % effective concentration was calculated.Results and discussion. A study of polycyclic derivatives of the framework series has identified two compounds with antiviral properties against the SARS-CoV-2 virus. Among bicyclo[3.3.1]nonane derivatives containing heterocyclic fragments, compound No. 15144 has showed an inhibitory effect against the SARS-CoV-2 virus. The protective effect of the compound was manifested in maximum tolerable concentration (MTC) (70.0 μg/ml) and ½ MTC (35.0 µg/ml). A decrease in virus titers under the influence of MTC by 0.95 lg TCD50/ml, in ½ MTC (35.0 μg/ml) – by 0.35 lg TCID50/ml has been detected. The effective concentration (EC50) value of the compound No. 15144 was 64.0 μg/ml, the MTC/EC50 ratio was 1.09. Compound No. 14838 (adamantane derivative containing carbocyclic fragments) had less pronounced antiviral activity. As a result of research, it has been established that sample No. 14838 at a dose of MTC (45.0 μg/ml) reduces the infectious titer by 0.78 lg TCD50/ml, in ½ MTC (22.5 μg/ml) by 0.15 lg TCD50/ml compared to the control. The EC50 value of compound No. 14838 was 37.0 μg/ml, the MTC/EC50 ratio was 1.22.

The purpose of this study was to evaluate efficiency of a competitive enzyme immunoassay which specifically detects antibodies that recognize the receptor-binding domain at the S1 subunit of SARS-CoV-2 coronavirus spike protein and block the formation of initiator infection complex between RBD and angiotensinconverting enzyme 2 (pseudo-neutralizing test, PNT) being applied at the stage of preclinical studies of anti- SARS-CoV-2 vaccine. We studied 37 animal blood sera (8 cows, 10 dogs) as well as 19 male and female transgenic mice of the B6.Cg-Tg(K18-ACE2)2Prlmn/HEMI line hemizygous for Tg(K18-ACE2)2Prlmn (Jackson Immunoresearch, West Grove, PA, USA)) immunized with candidate COVID-19 vaccine preparations containing SARS-CoV-2 Spike protein. In this study, 3 techniques were used for detection of antibodies to SARS-CoV-2 virus, as follows: 1) a pseudo-neutralizing test (PNT) to detect antibodies that block interaction between RBD and ACE-2; 2) neutralization test (RN) to detect virus-neutralizing antibodies, and 3) enzyme-linked immunosorbent assay to detect class G antibodies to RBD SARS-CoV-2. The results were expressed, respectively, as the suppression quotients (SC), titers of virus-neutralizing antibodies (VNA), and the positivity index (IP). The data obtained show a pronounced, statistically significant correlation between the results obtained by immunoassay methods with VNA titers determined in the studied animals by the virological neutralization test. E.g., the Spearman correlation quotients for VNA and SC titers, were, respectively, 0.9151; 0.8085, and 0.9207 for dogs, transgenic mice and cows. The Spearman quotient for VNA and PI titers was 0.8854 and 0.8955 for dogs and transgenic mice. Thus, in order to evaluate immunogenicity of vaccine preparations in our study, both methods are adequate and safe analogues to RN-ELISA for determination of IgG to RBD and PNT aoming for detection of antibodies blocking the formation of RBD/ACE-2 complex. However, the advantage of PNT is its versatility, eliminating the need to use different conjugates to detect antibodies in blood sera of different animal species. The data obtained for samples of three animal species (transgenic mice, dogs and cows) well agree with similar data obtained by us and other researchers for human blood sera, thus demonstrating high correlation between the results of PNT-like competitive tests to determine antibodies that block the formation of the RBD/ACE-2 complex, with VNA results in virologic neurtralization test (RN). Therefore, the proposed PNT technique may be used in preclinical and clinical trials of candidate vaccines and drugs.

Introduction. Despite the end of the COVID-19 pandemic, the problem of vaccine prevention of this disease appears highly relevant. The emergence and widespread distribution of the Omicron SARS-CoV-2 variant of concern (VOC) and its sublineages has dramatically reduced the efficacy of vaccination. The possible approach to solving this problem is to develop a nasal live attenuated vaccine capable of activating humoral, mucosal, and cell-mediated immunity, providing a prolonged immune response and cross-protection against different VOCs. The aim of the study was to determine the immunization efficacy with attenuated cold-adapted Wuhan-like SARS-CoV-2 D-D2 strain against homologous and heterologous challenges. Materials and methods. The study was conducted on an animal model of coronavirus pneumonia in golden Syrian hamsters. The efficacy of immunization was assessed by comparing the dynamics of weight, viral load in organs and histopathological changes in the lungs in immunized and unimmunized animals. Results. Single intranasal immunization of golden Syrian hamsters with D-D2 strain showed its high immunogenicity: seroconversion was evident in all immunized animals. Wuhan-like D-D2 strain provides highly effective protection of hamsters against the development of productive infection and pneumonia when challenged both with ancestral virus and heterologous strains related to Delta (AY.122) and Omicron (sublineages BA.1.1 and BA.5.2) variants. Conclusion. SARS-CoV-2 attenuation is a promising strategy for the development of a highly effective nasal live COVID-19 vaccine.

Introduction. The COVID-19 pandemic, etiologically related to SARS-CoV-2, was the longest-lasting pandemic for an acute respiratory disease and had a significant impact on demography, economics and politics globally. Experiences with this pandemic are significant for the sustainable development of human society. A detailed analysis of these experiences in epidemic control should include details of the pathogen evolution down to the regional level. The aim of the study was to establish the regularities of the COVID-19 epidemic process in connection with the change of the pathogen genetic variants on the territory of Primorsky Krai. Materials and methods. A retrospective epidemiological analysis of COVID-19 incidence and dynamics of circulation of SARS-CoV-2 genetic variants during the pandemic of this disease (11.03.2020–05.05.2023) in Primorsky Krai was carried out. Data was gathered from the Department of Rospotrebnadzor in Primorsky Krai, the Centre of Hygiene and Epidemiology in Primorsky Krai, as well as the G.P. Somov Research Institute of Epidemiology and Microbiology of the Russian Federation and Russian Platform for Aggregation of Information on Virus Genomes (VGARus). In particular, 1055 nucleotide sequences of full-length SARS-CoV-2 genomes from Primorsky Krai, among which 553 were sequenced at the G.P. Somov Research Institute of Epidemiology and Microbiology were included in analysis. Results. When analyzing the epidemic dynamics of COVID-19 in Primorsky Krai (2020–2023), 7 rises in incidence with different clinical and epidemiological symptoms depending on the genetic variants of the pathogen were identified. At the beginning of the pandemic in Primorsky Krai, as well as throughout Russia, Wuhan-like variants of SARS-CoV-2 were predominant, though later, Delta and Omicron genetic variants were in the majority. By the end of April — beginning of May 2023, the proportion of Omicron sub-variants (XBB.1.9.2 and XBB.1.16) in Primorsky Krai was higher than the Russian average and comparable to that in neighboring countries (Republic of Korea and Japan). Conclusion. Due to the ongoing evolution of SARS-CoV-2, the possibility of the emergence of new pathogens, the peculiarities of the geographical location as well as political and economic importance of Primorsky Krai, it is necessary to consistently improve regional capabilities for operational molecular virological monitoring.

Впервые РНК вируса SARS-CoV-2 была выявлена 8 декабря 2019 года у пациента с пневмонией. 31 декабря 2019 года Всемирная организация здравоохранения (ВОЗ) была оповещена о нескольких случаях вирусной пневмонии, вызванной неизвестным патогеном. 7 января 2020 года информация о новом вирусе была подтверждена, а сам вирус был отнесен к коронавирусам. В январе 2020 года ВОЗ объявила вспышку, связанную с SARS-CoV-2, а 11 марта 2020 года охарактеризовала принявшее мировой масштаб распространение болезни как пандемию. COVID-19 широко известен как заболевание, вызывающее респираторную дисфункцию, однако оно также связано с массой внелегочных проявлений: нарушение свертываемости крови, дисфункция миокарда и аритмия, острый коронарный синдром, острая почечная недостаточность, желудочно-кишечные расстройства, гепатоцеллюлярные повреждения, гипергликемия и кетоз, неврологические заболевания, глазные симптомы и дерматологические осложнения. В данном обзоре затронута эпидемиология, патогенез новой коронавирусной инфекции, а также поражения желудочно-кишечного тракта вирусом SARS-CoV-2.

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

Aim: To study the manifestations of the COVID-19 epidemic and the clinical and epidemiological characteristics of adult patients with a new coronavirus infection during the dominance of the Delta SARS-COV-2 in the Russian Federation.Materials and Methods: Study included patients aged ≥18 years with a laboratory-confirmed diagnosis of COVID-19, detected in the period from 09/01/2021 to 11/30/2021 (n= 2 619 298) in 85 Russian regions.Results: There were 2 periods of rise and decline in the COVID-19 incidence and mortality during the spread of the Delta SARS-CoV-2 in Russia: June-September and OctoberDecember 2021 (Wald – Wolfowitz criterion, p

Mutations in the SARS‑CoV‑2 genome make it possible to effectively escape defense mechanisms of the host, which explains the spread of infection among vaccinated or previously affected by the virus individuals.The aim of the study was to investigate the dynamics of mutations in the SARS‑CoV‑2 virus genome during the rise of the seasonal incidence in the Chuvash Republic.Materials and methods. Under conditions of the clinical diagnostic laboratory of the Federal Center for Traumatology, Orthopedics and Endoprosthetics of the Ministry of Health of Russia (Cheboksary), samples, containing SARS‑CoV‑2 RNA, taken in January-February and July-October, 2022 were tested using reverse transcription PCR. The “MBS-Test SARS‑CoV‑2 RNA” (Technical Specifications 21.20.23-068-26329720-2021, Russia) and “AmpliTest SARS‑CoV‑2 VOC v.3” (Series V017, Certificate of Registration No. 2022/16307, Russia) were utilized in compliance with the manufacturer’s instructions.Results and discussion. Variations in the sets of SARS‑CoV‑2 S gene mutations have been revealed in the studied samples obtained during different periods of the spread of SARS‑CoV‑2 coronavirus. Timely detection of various mutations in the virus genome at the beginning of the epidemiological season and the alleged rise in the incidence of coronavirus infection is valuable information for forecasting the rate of virus transmission. It can also be used to create vaccines (taking into account changes in the virus genome) and to choose the adequate tactics for treating coronavirus infection.

An important area of research concerns monitoring of immune response features in patients with SARS-CoV-2 infection as well as their analysis, as compared with characteristics of vaccine-mediated protection, in order to specify the determinants of cellular immune response. The aim of our work was to compare the state of cellular immune response in patients who underwent COVID-19, and in persons vaccinated with a peptide vaccine preparation. The study involved volunteers who suffered with COVID-19 of varying severity (n = 30), as well as persons who completed the full course of vaccination with the peptide vaccine (n = 27). For comparison, we took blood specimens from the volunteers before vaccination. Immunophenotyping of leukocytes was performed by the Lyse/No-Wash procedure (BD Bioscience, USA), and Cyto-Stat monoclonal antibodies (CD45-FITC, CD4-PE, CD8-ECD, CD3-PC5), CD45RA-PC7, CD45RO-PE (Beckman Coulter, USA), and analyzed with a DakoCytomation flow cytometer (Denmark). Determination of intracellular IFNγ (CD4+IFNγ+) was performed with the standard technique. Cytokine production was determined using reagent kits for detection of IFNγ, TNFα, IL-4, IL-8, IL-10 (Vector-Best JSC, Russia) with automatic enzyme immunoassay analyzer LAZURIT (Dynex Technologies, USA). As based on the results obtained, we have shown that cellular immunity was developed after vaccination and infection with COVID-19. However, the most pronounced immune response was recorded in the COVID-19 reconvalescents, i.e., more than 60% of these patients showed an increased number of CD4+T-memory helper cells (8.7 (0.5-12.1) % versus 0.3 (0.1-0.5) % in the comparison group, p < 0.05) as well as proportion of CD4+IFNγ+T lymphocytes (4.2 (1.8-4.3) % versus 0.4 (0-0.8) % in the comparison group, p < 0.05). Moreover, we revealed an increased functional reserve of cells in terms of TNFα, IL-8, IL-10 production. One month after vaccination of volunteers with the peptide-based preparation, the total pool of memory T lymphocytes was apparently dominated by CD8+T memory cells (CD45+CD8+CD45RA-CD45RO+). A significant increase was found in the average levels of CD4+IFNγ+ activated cells (8.2-fold), as well as in values of ConA-induced IL-4 production (3.3 (1.1-4.5) pg/mL, and 2.8 (1.7-3.9) pg/mL, respectively versus 1.3 (0.1-2.4) pg/mL in the control group, p < 0.05). The data obtained are in accordance with information available in the literature concerning development of cellular immune responses to SARS-CoV-2, which results from a past illness, or measures for the specific prevention of COVID-19. Further search for cellular correlates of protection against a new coronavirus infection will allow us to revise the current vaccination strategy and develop an optimal approach to COVID-19 prevention.

Objective: To determine the factors associated with prolonged hospital-stay after appendectomy in SARS-CoV-2 pandemic., Material and Methods: A retrospective observational cohort study included 420 patients after surgery for acute appendicitis between March 2019 and March 2020, April 2020 and April 2021. There were 336 patients before the SARS-COV-2 pandemic, and 84 ones underwent surgery during the pandemic., Results: Incidence of prolonged hospital stay was 15% and 26%, respectively (RR 1.76). RR is more than 1 and assumes SARS-CoV-2 infection as a risk factor., Conclusion: There is an association between SARS-CoV-2 infection and prolonged hospital-stay after surgery for acute appendicitis (RR 1.76).

Background. The novel coronavirus infection (COVID-19) often manifests in children as diarrhea, vomiting, abdominal pain, and some children develop acute appendicitis. To elucidate the role of SARS-CoV-2 in the development of acute appendicitis, a more detailed study of the presence of its genetic material in the tissue of the appendix., Objective: Determination of SARS-CoV-2 RNA in appendices of children with COVID-19 by fluorescence in situ hybridization (FISH)., Material and Methods: A retrospective analysis of case histories and morphological analysis using FISH of appendices of pediatric patients with established clinical diagnosis of acute appendicitis and confirmed infection with SARS-CoV-2 was performed. The material was divided into 3 groups: 1st -appendices obtained during appendectomy in children with established clinical diagnosis of «coronavirus infection» (COVID-19, PCR+) ( n =42; mean age 10.8 years); 2nd - appendices of children ( n =55; mean age 9.7 years) with acute appendicitis obtained before the onset of the COVID-19 pandemic; 3rd (control) group ( n =38; mean age 10.3 years) - autopsy material of the appendices (intact)., Results: In all samples of the appendices of the 1st group, a positive SARS-CoV-2 viral RNA signal was noted in the cytoplasm of most epithelial cells and single immunocompetent cells. The signal intensity remained the same in all slides, regardless of age. In all samples obtained from patients without COVID-19 (groups 2 and 3), confocal microscopy did not reveal a signal, which indicates successful adaptation of the FISH method in this study and excludes the false positive results., Conclusion: In the epithelium of the appendices of children of different age with COVID-19, the FISH method revealed SARS-CoV-2 RNA, which does not exclude the association between viral invasion and the development of acute appendicitis.

Introduction. At the beginning of December 2019, humanity has faced a new problem caused by coronavirus. In Hubei province of central China, epidemic events associated with severe primary viral pneumonia in humans began to develop. The isolated etiological agent was identified as a representative of Coronaviridae family. The global pandemic associated with the new coronavirus infection, acute respiratory syndrome type 2 (Severe acute respiratory syndrome 2, SARS-CoV-2), has become a challenge for humanity. Objective. In our work, we assessed the replicative ability and pathogenesis of the SARS-CoV-2 virus in hamsters. Materials and methods. Syrian hamsters (n=16) randomly divided into two groups were used in experiment. The first group was infected intranasally with the SARS-CoV-2 virus, strain SARS-CoV-2/human/KAZ/KZ_Almaty/2020 deposited in GenBank under number MZ379258.1. The second group remained as a control group. Clinical manifestations of the disease in hamsters were observed within 14 days. Samples were collected on days 3, 5, 7, 9, 12, and 14 postinfection. The obtained samples were tested for viral isolation in cell culture, histological examination and analysis of viral RNA by RT-PCR. Results. SARS-CoV-2 virus isolates showed efficient replication in the lungs of hamsters, causing pathological lung lesions in animals infected intranasally. Clinical manifestations of the disease in hamsters infected with this virus were characterized by a decrease in temperature and body weight, wetness and ruffled fur, and frequent stroking of the nasal planum. High virus titers were observed following the virus isolation in cell cultures from nasal, oral swabs and lungs of animals infected intranasally. Pathological autopsy demonstrated pathological changes in the lungs. Moreover, transmission by airborne droplets has been established when a healthy hamster was kept together with animals infected using the intranasal method. Conclusion. In conclusion, our study showed that the Syrian hamster model is a useful tool for studying the SARS-CoV-2 pathogenesis, as well as testing vaccine candidates against acute respiratory syndrome type 2.

Aim. To identify predictors of the development of thromboembolic complications (TECs) in patients with severe SARS-CoV-2 coronavirus infection. Materials and methods. A single-center observational retrospective study included 1634 patients with a confirmed diagnosis of SARS-CoV-2 coronavirus infection. The patients were divided into 2 groups depending on the availability of the feasibility study. The criterion for inclusion of patients in the main group was the presence of venous feasibility studies in 127 patients (group I), the comparison group consisted of 1507 patients in whom the course of COVID-19 was not complicated by the development of feasibility studies (group II). Results. When performing computed tomography of the chest organs, it was revealed that patients with a feasibility study had a higher percentage of lung tissue damage than patients in the comparison group: 55% [37.5; 67.5] and 37.5% [25.0; 47.5], respectively (p0.001). The average values of C-reactive protein in I patients group were 129 [60.1; 211] ng/l, which was significantly higher than in II patients group – 41.0 [12.2; 97.6] ng/l (p0.001), interleukin-6 – 176 [52.9; 471] pg/ml and 39.4 [11.0; 107] pg/ml (p0.001), respectively. A one-factor regression analysis proved a significant contribution of comorbid pathology to the development of feasibility studies in patients with COVID-19. The presence of three nosologies at the same time: arterial hypertension, coronary heart disease (CHD) and chronic kidney disease increased the probability of a feasibility study by 4.81 times (odds ratio 4.8117, 95% confidence interval 3.2064–7.2207), in patients with arterial hypertension, CHD, chronic kidney disease and type 2 diabetes – by 5.63 times (odds ratio 5.6321, 95% confidence interval 3.1870–9.9531). Conclusion. The presence of severe comorbid pathology significantly increased the risk of developing a feasibility study in patients with COVID-19. The most significant predictors of the development of feasibility studies in patients with severe SARS-CoV-2 coronavirus infection. They are: CHD, arterial hypertension and type 2 diabetes.

Scientific relevance. The use of recombinant antigens in vaccine production is limited because vaccines based on such antigens tend to have low immunogenicity. However, a COVID-19 vaccine that combines recombinant SARS-CoV-2 spike glycoprotein as its antigen and virus-like immune-stimulating complexes (ISCOMs) as its adjuvant (Nuvaxovid) induces a protective virus-neutralising response. The State Research Center of Virology and Biotechnology “Vector” (hereinafter, Vector) has developed the ISCOM adjuvant Matrix-V, which plays a key role in inducing virus-neutralising antibodies. Studying Matrix-V will provide for the wide use of recombinant antigens combined with this adjuvant in the development and production of novel Russian vaccines.Aim. This study aimed to evaluate the humoral immune responses of experimental animals to intramuscular injections of a complex combining the recombinant Wuhan-type SARS-CoV-2 spike RBD antigen and the virus-like ISCOM adjuvant containing Quillaja saponaria saponins.Materials and methods. The Matrix-V ISCOM adjuvant was produced using Vector’s proprietary technology, which involves cross-flow filtration through Sartorius VivaFlow cassettes. To determine the saponin and residual detergent concentrations in Matrix-V, the authors conducted high-performance liquid chromatography. Having produced the recombinant SARS-CoV-2 RBD antigen, the authors used electron microscopy to analyse the ultrastructure of the ISCOM–antigen complex. In the study of the ISCOM–antigen complex, 25 female Balb/c mice (5 groups) and 15 male and female outbred guinea pigs (3 groups) received two intramuscular injections with a 14-day interval. Serum tests relied on virus neutralisation (VN) and enzyme-linked immunosorbent assay (ELISA) methods and used antigens of 8 SARS-CoV-2 variants (State Collection of Viruses and Rickettsia, Vector). The authors used Statistica 10 to analyse the results.Results. Two injections of the SARS-CoV-2 RBD antigen (mice: 7 μg, guinea pigs: 1 μg) alone did not induce statistically significant virus-neutralising antibody responses, as shown by the VN results. Two injections of the SARS-CoV-2 RBD antigen (mice: 7 μg, guinea pigs: 1 μg) adjuvanted with Matrix-V (25 μg) resulted in geometric mean antibody titres of 1:83–1:178 (mice) and 1:174–1:587 (guinea pigs) in the VN tests with the Wuhan variant. One injection of the antigen (1 μg or 7 μg) with Matrix-V (25 μg) induced antibodies only in individual cases, as demonstrated by the VN and/or ELISA results. The most intensive immune response was observed in ELISA tests with the Delta variant after two injections of the Ecto-S-Wuhan (1 μg) and Matrix-V (25 μg) complex. Immune responses did not differ between the group that received two injections of the Ecto-S-Wuhan antigen (1 μg) without the ISCOM adjuvant and the negative control group (titres below 1:100; p=0.95). Two injections of the SARS-CoV-2 RBD antigen (7 μg) without the ISCOM adjuvant induced antibodies in mice (titres between 1:248 and 1:1477).Conclusions. Two intramuscular injections of the complex containing the recombinant SARS-CoV-2 RBD antigen and the Matrix-V ISCOM adjuvant induce virus-neutralising antibodies. The approach proposed by the authors has the potential for use in the development of immunobiological medicinal products to prevent and treat a wide range of infectious diseases.

Distrust of vaccines is one of the key problems of modern healthcare both in Russia and abroad. Mass vaccination against SARS-CoV-2 provoked a large number of social media narratives. Online communities play an important role in the formation and dissemination of narratives. The complex system of numerous online platforms for discussing the topic of vaccination on a social network deserves a special description. The purpose of the study is to construct a typology of all significant communities of the popular Russian social network “VKontakte” that publish content on the topic of vaccination against COVID-19 (01/01/2020 – 03/01/2023) and describe it in terms of lobbied narratives. Big data collection and analysis methods were used, as well as narrative analysis. Of the 131,119 communities that published at least one vaccination message during the study period, 691 were selected based on self-positioning criteria (name, description) and/or the number of SARS‑CoV-2 vaccination messages above the established threshold. 14 thematic categories of communities have been identified, the self-positioning of which allows reconstructing narratives about forced vaccination and the right to choose; health care and debate about the benefits/effectiveness of vaccination; conspiracy theories; beneficiaries and trust in the authorities; pseudoscience, vaccination myths and scientific knowledge; childcare and parental rights; contrasting medical science with religious beliefs. Narratives formed by online communities signify a pronounced polarization of opinions in the digital society regarding SARS-CoV-2 vaccination. The “pro-waxer” and “anti-vaxxer” narratives are reconstructed. Quantitatively “anti-vaxxer” communities significantly predominate over “pro-waxer” ones.

The coronavirus pandemic caused by the SARS-CoV-2 virus, which humanity resisted using the latest advances in science, left behind, among other things, extensive genetic data. Every day since the end of 2019, samples of the virus genomes have been collected around the world, which makes it possible to trace its evolution in detail from its emergence to the present. The accumulated statistics of testing results showed that the number of confirmed cases of SARS-CoV-2 infection was at least 767.5 million (9.5 % of the current world population, excluding asymptomatic people), and the number of sequenced virus genomes is more than 15.7 million (which is over 2 % of the total number of infected people). These new data potentially contain information about the mechanisms of the variability and spread of the virus, its interaction with the human immune system, the main parameters characterizing the mechanisms of the development of a pandemic, and much more. In this article, we analyze the space of possible variants of SARS-CoV-2 genetic sequences both from a mathematical point of view and taking into account the biological limitations inherent in this system, known both from general biological knowledge and from the consideration of the characteristics of this particular virus. We have developed software capable of loading and analyzing SARS-CoV-2 nucleotide sequences in FASTA format, determining the 5’ and 3’ UTR positions, the number and location of unidentified nucleotides (“N”), performing alignment with the reference sequence by calling the program designed for this, determining mutations, deletions and insertions, as well as calculating various characteris tics of virus genomes with a given time step (days, weeks, months, etc.). The data obtained indicate that, despite the apparent mathematical diversity of possible options for changing the virus over time, the corridor of the evolutionary trajectory that the coronavirus has passed through seems to be quite narrow. Thus it can be assumed that it is determined to some extent, which allows us to hope for a possibility of modeling the evolution of the coronavirus.

Introducere: Cancerul la copii este o afecțiune rară în rândul populației pediatrice și reprezintă aproximativ 0,5-1% din totalul bolilor oncologice. În Republica Moldova, aproximativ 90 de copii sunt diagnosticați anual cu tumori maligne. Supraviețuirea copiilor cu cancer s-a îmbunătățit semnificativ în timp, dar acesta rămâne o cauză importantă a îmbolnăvirii și mortalității în rândul copiilor. În cazul patologiei oncologice, infecțiile virale și bacteriene dobândite în societate pot duce la întârzierea tratamentului chimioterapeutic, crescând astfel riscul de recidivă și rezistența bolii, sporind astfel mortalitatea. Copiii cu afecțiuni hematologice maligne au, în general, un prognostic mai favorabil în ceea ce privește infecția cu COVID-19 decât adulții cu aceleași patologii, dar riscul lor de spitalizare și deces este mult mai mare în comparație cu populația pediatrică generală. Scopul studiului: Determinarea ratei de infectare cu SARS-CoV-2 la copii cu hemoblastoze, dinamicii și supraviețuirii. Materiale și metode: Acesta este un studiu retrospectiv efectuat în cadrul Departamentului de Hematologie Pediatrică al Institutului Oncologic în perioada pandemiei SARS-CoV-2, din martie 2020 până în martie 2022. Rezultate proprii: Din totalul pacienților spitalizați și tratați în institutul oncologic la Departamentul de Hematologie Pediatrică (125 de pacienți), 33 (26,4%) au avut o infecție cu SARS-CoV-2, dintre aceștia 3 au avut COVID-19 de două ori. Majoritatea pacienților, adică 26 (78,78%), au avut leucemie limfoblastică acută, 1 (3,03%) a avut limfom Hodgkin, iar 2 (6,06%) au avut limfom Burkitt și limfoame non-Hodgkin. Între simptomele clinice, 11 pacienți (30,5%) au avut febră > 38 grade Celsius, iar 10 pacienți (27,7%) au avut febră, în timp ce 12 copii (33,3%) nu au prezentat niciun simptom, având doar testul pozitiv pentru COVID-19. Dintre copiii cu diagnosticul de infecție COVID-19, 10 (27%) cazuri au fost înregistrate la copii înainte sau în același timp cu diagnosticul hematologic principal, 25% (9 pacienți) erau în perioada de tratament de susținere intermediară, iar un caz (2,7%) a avut loc în timpul terapiei de reinducție și terapiei refractare, respectiv. La pacienții cu semne radiologice de pneumonie virală, s-a observat o predominanță nesemnificativă a numărului absolut de limfocite față de neutrofile. Din punct de vedere imagistic, au fost confirmate 7 cazuri de pneumonie virală bilaterală, 1 caz de pneumonie virală bilaterală severă, RX 4, care a dus la deces, și un caz de pneumonie virală bilaterală datorată infiltrării leucemoide, care, de asemenea, a condus la deces. Decompensarea la un copil a avut loc aproximativ cu 2 luni înainte de diagnosticul COVID-19. Concluzii: La majoritatea pacienților pediatrici cu afecțiuni hematologice maligne, infecția cu COVID-19 nu duce la o progresie severă. Cu toate acestea, această infecție duce la întreruperea terapiei specifice, iar consecințele pe termen lung nu sunt încă suficient de studiate.

Введение. К настоящему времени свыше 270 миллионов человек переболели COVID-19, более 2 миллионов умерло. По сей день ежедневно в мире регистрируются десятки тысяч новых случаев заболевания, поэтому оценка методов диагностики SARS-CoV-2 ассоциированной патологии остается высоко актуальной. Цель исследования: оценить вариабельность клинических и лабораторных показателей у пациентов с инфекцией SARS-CoV-2 в зависимости от результатов серологической диагностики. Материал и методы. 170 пациентов (88 женщин, 82 мужчины в возрасте от 23 до 90 лет) с диагнозом «Вирусная инфекция SARS-CoV-2. Внебольничная интерстициальная пневмония» были обследованы в соответствии с протоколом, у 80 из них определили содержание в крови ИЛ-1β, ИЛ-6, ИЛ-18, CXCL8, и интерферона-α. Результаты. Установлено, что только в 34,09% отрицательный результат ПЦР на наличие генетического материал вирусов SARS-CoV-2 у пациентов с диагнозом внебольничная интерстициальная пневмония совпадал с негативным результатом определения IgG и/или IgM к вирусному антигену. Положительный результат ПЦР подтверждался наличием повышенного уровня антител в 64,29% случаев. У ПЦР позитивных пациентов достоверно чаще, чем у ПЦР негативных определялась дыхательная недостаточность 2-3 степени (в 40,28% и 16,32% случаев соответственно, p

Most techniques for evaluation of T-cell immunity are laborious and unsuitable for routine laboratory diagnostics, thus encouraging researchers to look for accessible and reproducible tests. The purpose of our study is to compare three methods aimed for evaluation of cellular immune response levels to the SARS-CoV-2 viral antigens in patients who have been ill and vaccinated against a new coronavirus infection. We have examined 26 persons who experienced mild or moderate COVID-19 (group 1); 19 people vaccinated twice with Sputnik V, who did not have clinical COVID-19 (group 2); 21 subjects who had COVID-19 and were twice vaccinated with Sputnik V (group 3), and 14 persons who had COVID-19 twice (group 4). Peripheral blood mononuclear cells were isolated by gradient centrifugation. The first tested technique was performed as follows: the mononuclear cells were incubated with the S-protein of the SARS-CoV-2 virus, and stained with fluorescently labeled antibodies. The percentage of CD8highCD107a was counted by means of BD FACS Canto II flow cytometer. When assessed by the ELISpot method with “Human IFN-γ ELISpot” kit, IFNγ production was stimulated by SARS-CoV-2 S-protein, or a mixture of SARS-CoV-2 protein peptides in the “Corona-T-test” kit. There were no significant differences in the levels of CD107a expression on CD8high cells between the groups 1, 2, 3, and 4, as well as in amounts of IFNγ producers against SARS-CoV-2 S-protein when using “Human IFN-γ ELISpot” kit. Production of IFN was significantly lower in group 3 (hybrid immunity), i.e., 317.29±19.04 pg/ml compared to groups 1 and 2 (post-infection and post-vaccination immunity), i.e., 454.95±20.32 and 470.77±26.24 pg /ml, respectively. The relative level of IFNγ -producing cells in group 2 was higher (22.34±3.77) versus 16.83±2.35 in group 1, and 15.46±1.83 in group 3, whereas the relative levels of IFNγ did not differ in these groups. Stimulation with full-length S-protein showed a significant reduction in the number of spots in group 4 (breakthrough immunity), i.e., 30.59±2.29 vs 58.97±4.47 in group 3. Stimulation with a mixture of SARS-CoV-2 peptides in group 4 vs group 3 revealed a significantly increased number of IFNγ -producing cells (86.72±7.20 versus 69.38±5.53) and higher IFNγ production (991.25±65.18 pg/ml versus 760.76±50.70 pg/ml). Appropriate relative values were as follows: 10.30±2.77 versus 8.61±2.66, and 68.10±9.41 versus 48.35±8.15, respectively. The results of three methods for evaluation of cellular immune response correlate positively with each other, but at different significance levels.

The paper analyzes a set of equations that adequately predict the IC50 value for SARS-CoV-2 main protease inhibitors. The training set was obtained using filtering by criteria independent of prediction of target value. It included 76 compounds, and the test set included nine compounds. We used the values of energy contributions obtained in the calculation of the change of the free energy of complex by MMGBSA method and a number of characteristics of the physical and chemical properties of the inhibitors as independent variables. It is sufficient to use only seven independent variables without loss of prediction quality (Q² = 0.79; R²prediction = 0.89). The maximum error in this case does not exceed 0.92 lg(IC50) units with a full range of observed values from 1.26 to 4.95.

Objective: To evaluate efficacy and safety of hypoxic-hyperoxic therapy in rehabilitation after SARS-CoV-2 pneumonia., Material and Methods: There were 44 patients aged 49-75 years in early recovery period after previous SARS-CoV-2 pneumonia (ICD-10 U07.1 and U07.2). Patients were divided into 2 groups depending on treatment strategy: group 1 ( n =23) - rehabilitation treatment with therapeutic exercises, massage and physiotherapy; group 2 ( n =21) - basic procedures with hypoxic-hyperoxic therapy., Results: At initial evaluation, we found positive tendencies of rehabilitation in both groups. There were no side effects associated with hypoxic-hyperoxic therapy in the second group. Patients positively perceived this method of rehabilitation. There were significant between-group differences in exercise tolerance ( p <0.05). These data indicate more favorable physical recovery in the second group and similar improvement of psycho-emotional status in both groups., Conclusion: Hypoxic-hyperoxic therapy is effective and safe approach in rehabilitation of patients with previous SARS-CoV-2 pneumonia. It is necessary to continue searching for effective methods of rehabilitation and develop accurate rehabilitation methods for various groups of patients.

In the present review, we consider theoretical background and results of the first studies of SARS-CoV-2 effect on the intestine and its microbiome. The data obtained indicate the long-term virus persistence in the cells of intestinal mucosa. In addition, acceleration of microbial cells and microbial metabolites translocation associated with inflammatory processes in the intestinal endothelial cells caused by the virus was also discussed. COVID-19 has a great impact on structure and functional activity of the intestinal microbiome. The decrease in species diversity and minor species dominations that are not found in the microbiome of healthy controls were observed. The gut microbiome is considered to be an important influencer on COVID-19 progression and outcome.

Aim. To study and characterise the features of the course of coronavirus infection in a domestic cat model, as well as to assess the danger of SARSCoV-2 isolated in Russia for these animals based on the data obtained, with the possibility of extrapolating to wild felines.Material and Methods. For the study, model animals – Felis silvestris catus – were divided into 3 groups. The viral strain of SARS-Cov-2/human/RUS/Nsk-FRCFTM-1/2020 was cultivated on Vero E6 cell culture and then administered intranasally in a volume of 200 μl, 105TCID50/ml, to animals from the first and second groups. Model animals from the first group were euthanized and lung fragments were taken on 6–day post infection (d.p.i.), animals from the second group – on 14 d.p.i. The third group – the control group, was injected with saline in an equivalent volume. Histological sections colored with hematoxylin and eosin were investigated for pathomorphological changes in lung tissue using light microscopy.Results. According to the obtained results the pathomorphological picture in the lungs of experimental animals indicates the course of interstitial pneumonia for both 6 and 14 d.p.i. In addition, it has been determined that by 14 d.p.i. the growth of fibrous tissue in the lungs begins to be visualised, indicating the beginning of light regenerative processes.Conclusion. The study showed that cats are susceptible to the SARS-CoV-2 virus, and these model animals are characterized by the emergence of clinical manifestations and morphological patterns in the lungs, which correspond to interstitial pneumonia.

Aim. In vitro evaluation of the inhibitory activity of aqueous extracts and dry ethanol extracts of St John's wort (Hypericum perforatum L.) on the replication of SARS-CoV-2 according to three experimental schemes – direct inactivation (neutralisation) of the virus as well as "prevention" and "treatment" of cells.Materials and Methods. The laboratory strain SARS-CoV-2/human/RUS/Nsk-FRCFTM-1/2020 was passed on Vero cell culture. Water extracts and dry ethanol extracts of parts of H. perforatum L. collected during the flowering period in the Novosibirsk region were prepared. Dry extracts were dissolved in DMSO. Comparison samples are dry ethanol extracts of chaga, cloves and black tea.Results. It is shown that the aqueous extract of grass (a mixture of flowers with leaves) of H. perforatum L. with direct inactivation of the virus it is active in dilution of 1/4096. For the dry ethanol extract of the herb H. perforatum L., 50 % effective concentrations (EC50) were found equal to 2.44±0.87; 8.79±1.91 and 14.65±1.91 μg/ml respectively with direct inactivation as well as according to the "preventive" scheme and with the "treatment" of cells. Taking into account cytotoxicity, as well as in comparison with control samples, the values of selective indices (SI50) of the studied herbal preparations during direct inactivation were higher than with other experimental schemes and were distributed as follows (in descending order): 204.92; 153.68; 115.27; 32.01 and 21.33 for dry ethanol extracts of black tea from India, cloves, herbs, a mixture of flowers with leaves, of H. perforatum, chaga and the stems of H. perforatum respectively. The HPLC method has shown that the ethanol extract of the herb H. perforatum L. contains a greater amount of flavonoids than the extract of stems. Nevertheless, antiviral activity was also detected for the extract of stems of this plant with EC50 equal to 14.65±1.91; 78.13±20.05 and 117.19±15.31 μg/ml (according to three experimental schemes), respectively.Conclusion. For the preparation of antiviral drugs the whole plant of H. perforatum L., including stems, can be used as raw materials.

Introduction: The development of drugs against SARS-CoV-2 continues to be crucial for reducing the spread of infection and associated mortality. The aim of the work is to study the neutralization of the SARS-CoV-2 virus with interferon gamma preparations in vitro., Materials and Methods: The activity of recombinant human interferon gamma for intramuscular and subcutaneous administration of 500,000 IU and for intranasal administration of 100,000 IU against the SARS-CoV-2 virus in vitro was studied. The methodological approach of this study is based on the phenomenon of a decrease in the number of plaques formed under the action of a potential antiviral drug., Results: The antiviral activity of recombinant interferon gamma has been experimentally confirmed, both in preventive and therapeutic application schemes. The smallest number of plaques was observed with the preventive scheme of application of the tested object at concentrations of 1000 and 333 IU/ml. The semi-maximal effective concentration (EC50) with the prophylactic regimen was 24 IU/ml., Discussion: The preventive scheme of application of the tested object turned out to be more effective than therapeutic one, which is probably explained by the launch of the expression of various interferon-stimulated genes that affect to a greater extent the steps of virus entry into the cell and its reproduction., Conclusion: Further study of the effect of drugs based on recombinant interferon gamma on the reproduction of the SARS-CoV-2 virus for clinical use for prevention and treatment is highly relevant.

Introduction: The development of the COVID-19 pandemic has stimulated the scientific research aimed at studying of the mechanisms of formation the immunity against SARS-CoV-2. Currently, there is a need to develop a domestic simple and cost-effective specific method suitable for monitoring of T-cell response against SARS-CoV-2 in reconvalescents and vaccinated individuals., Aim: Development of a screening method for evaluation specific T-cell immunity against SARS-CoV-2., Materials and Methods: Total 40 individuals who had mild to moderate COVID-19 and 20 healthy volunteers who did not have a history of this disease were examined. The presence and levels of IgG and IgM antibodies to SARS-CoV-2 were identified in participants sera by ELISA using the diagnostic kits from JSC Vector-Best (Novosibirsk, Russian Federation). Antigenic stimulation of mononuclear cells was carried out on commercial plates with adsorbed whole-virion inactivated SARS-CoV-2 antigen (State Research Center of Virology and Biotechnology VECTOR Novosibirsk, Russian Federation). The concentration of IFN- was measured in ELISA using the test systems from JSC Vector-Best (Novosibirsk, Russian Federation). The immunophenotyping of lymphocytes was performed on a flow cytometer Cytomics FC500 (Beckman Coulter, USA). Statistical data processing was carried out using the Microsoft Excel and STATISTICA 10 software package., Results: Stimulation of mononuclear cells isolated from the peripheral blood with whole-virion inactivated SARS-CoV-2 antigen fixed at the bottom of the wells of a polystyrene plate showed a significantly higher median response in terms of IFN- production in 40 people who had history of COVID-19 compared to 20 healthy blood donors (172.1 [34.3575.1] pg/ml versus 15.4 [6.925.8] pg/ml, p 0.0001). There was no difference in median IFN- levels in supernatants collected from unstimulated mononuclear cells from COVID-19 reconvalescents and healthy donors (2.7 [0.411.4] pg/ml versus 0.8 [0.023.3] pg/ml, p 0.05). The overall sensitivity and specificity of this method were 73% (95% CI 5888%) and 100% (95% CI 100100%), respectively, at a cut-off of 50 pg/ml., Conclusion: The developed method for assessment of the cellular immune response to SARS-CoV-2 can be used as a screening method for monitoring the T-cell response in a population against a new coronavirus infection in recovered people.

Introduction: SARS-CoV-2, a severe acute respiratory illness virus that emerged in China in late 2019, continues to spread rapidly around the world, accumulating mutations and thus causing serious concern. Five virus variants of concern are currently known: Alpha (lineage B.1.1.7), Beta (lineage B.1.351), Gamma (lineage P.1), Delta (lineage B.1.617.2), and Omicron (lineage B.1.1.529). In this study, we conducted a molecular epidemiological analysis of the most prevalent genovariants in Moscow and the region. The aim of the study is to estimate the distribution of various variants of SARS-CoV-2 in Moscow city and the Moscow Region., Materials and Methods: 227 SARS-CoV-2 sequences were used for analysis. Isolation of the SARS-CoV-2 virus was performed on Vero E6 cell culture. Sequencing was performed by the Sanger method. Bioinformatic analysis was carried out using software packages: MAFFT, IQ-TREE v1.6.12, jModelTest 2.1.7, Nextstrain, Auspice v2.34., Results: As a result of phylogenetic analysis, we have identified the main variants of the virus circulating in Russia that have been of concern throughout the existence of the pandemic, namely: variant B.1.1.7, which accounted for 30% (9/30), AY.122, which accounted for 16.7% (5/30), BA.1.1 with 20% (6/30) and B.1.1 with 33.3% (10/30). When examining Moscow samples for the presence of mutations in SARS-CoV-2 structural proteins of different genovariants, a significant percentage of the most common substitutions was recorded: S protein D614G (86.7%), P681H/R (63.3%), E protein T9I (20.0%); M protein I82T (30.0%), D3G (20.0%), Q19E (20.0%) and finally N protein R203K/M (90.0%), G204R/P (73.3 %)., Conclusion: The study of the frequency and impact of mutations, as well as the analysis of the predominant variants of the virus are important for the development and improvement of vaccines for the prevention of COVID-19. Therefore, ongoing molecular epidemiological studies are needed, as these data provide important information about changes in the genome of circulating SARS-CoV-2 variants.

The search for predictors of the severe course of COVID-19 was relevant both during the pandemic and at the present time. The aim of the study was to analyze the relationship of cytokine levels in patients with EН before SARS-CoV-2 infection with the incidence of coronavirus pneumonia. Materials and methods. From the database of 290 patients with stage II EAG who have been under observation for 8–12 years with annual blood sampling to determine cytokine levels, COVID-19 survivors were selected (mild without pneumonia and moderate to severe, pneumonia CT 1–2, CT-3). Anamnestic levels of IL-1β, IL-1α, IL-1ra, IL-18, IL-18 BP, IL-37, IL-6, sIL-6r, M-CSF, VEGF-A, IL-34 and HMGB1) in the blood serum of patients with stage II EH were analyzed (method ELISA). The analysis of the obtained results was carried out using Stat Soft Statistica 13.5. Results and discussion. Patients with EH and COVID-19 with pneumonia (CT I-II) after SARS-CoV-2 infection 2–6 months before the infectious disease had significantly higher serum levels: IL-1α (p 0.05) and a decrease in IL-37 (p 0.001). During multivariate correlation analysis, a statistically independent relationship between an increase in the incidence of viral pneumonia in patients with stage II EН was confirmed only for IL-37 with a blood level of less than 60.2 pg/ml (regression coefficient — 2.21, standard error — 0.28, t criterion — 6.12, relative risk — 2.52, criterion Walda — 7.92, p = 0.006). When studying circadian rhythms of cytokine content in blood serum in patients of the analyzed groups, calculating the strength of correlations of anamnestic evening IL-37 levels in patients with stage II EР at 19.00–20.00 with the frequency of pneumonia against the background of SARS-CoV-2 infection, it has greater specificity and sensitivity (specificity — 0.75, sensitivity — 0.82) than morning concentrations. Considering that data on circadian rhythms were obtained in a limited number of patients, further monitoring is necessary, which is carried out by our scientific group. It should be noted that patients with essential hypertension are pathogenetically heterogeneous, including in terms of cytokine regulation. The study of this area will make it possible to personalize cytokine phenotypes of the disease and develop new methods for calculating the prognosis of both cardiovascular complications and features of the course of infectious diseases.

Relevance. The new coronavirus infection (COVID-19) is still a public health problem and a threat to socio-economic well-being. Most studies have focused predominantly on humoral immunity, and there are no data on the cellular composition of blood in dynamics. Aim. To study the dynamics of changes in blood cellular composition depending on the type of immunity formed (natural, hybrid, breakthrough, postvaccinal) to SARS-CoV-2 virus. Materials and Methods. A total of 130 volunteers participated in the study. Immunophenotyping of peripheral blood leukocytes using flow cytometry was performed. The presence of specific IgG antibodies to N-protein SARS-CoV-2, total IgA and cytokines (IL-4, IL-10, IFN-γ, TNF-α) was assessed in serum by ELISA. Results and Discussion. A statistically significant increase in BL was recorded in volunteers with hybrid immunity 1 month (14,0% (12,3–16,4%)) after vaccination compared to healthy volunteers (9,1% (6,4–10,2%), p = 0,0007) and people with primary COVID-19 infection (10,2% (8,3–12,1%), p = 0,0134). In volunteers with natural and hybrid immunity, as well as in revaccinated people, an increase in B1-cells (CD3-CD19+CD5+CD27-) was observed during 3–9 months of observation. It is shown that the increase of B-lymphocytes with «switched» class of synthesized antibodies was detected in people with breakthrough immunity. Increased levels of T-lymphocytes expressing HLA-DR were recorded in all individuals during 6–9 months of follow-up. Volunteers with breakthrough immunity showed a significant increase in the positivity index when assessing the presence of specific IgG class antibodies to the coronavirus N-protein compared with volunteers with natural and hybrid immunity. Conclusions. Vaccination promotes protective immunity sufficient for timely activation of memory T- and B-cells in breakthrough immunity and maintenance of immunologic efficacy in hybrid immunity against COVID-19. The results help to assess the strain of innate and adaptive immunity in novel coronavirus infection and to fill gaps in the understanding of immunopathogenesis in COVID-19.

Представлена гипотеза формирования цитокин-опосредованной дисрегуляции иммунного ответа у человека при внедрении в организм коронавируса 2 (SARS-CoV-2). Выделены некоторые морфологические особенности данного вируса, способствующие его проникновению в организм и генерации сигнала для формирования противовирусной иммунной защиты. Определено, что интерлейкины 1, 6 и 10 стимулируют системное воспаление, тогда как интерлейкины 2, 7 и 15 регулируют адаптивные иммунные ответы CD8+ T-клеток. Показано, что защитное действие интерферонов λ1–4 изменяет баланс Т-хелперов 1-го и 2-го порядка и тем самым сохраняет иммунный гомеостаз. Тем не менее у больных COVID-19 CD8+ T-клетки демонстрируют паттерны функционального истощения на фоне развивающегося цитокинового шторма. Вместе с тем при достаточных резервных возможностях иммунной системы человека может развиться и адаптивный иммунный ответ, потенцируемый интерфероновой, интерлейкиновой и гуморальноклеточной защитой организма от вируса SARS-CoV-2. Однако на фоне цитокин-опосредованной дисрегуляции Т-клеточного иммунитета и прогрессирующего гипервоспаления у пациентов с тяжелым течением COVID-19 в крови выявляется выраженная лейкопения, нарушение процентного соотношения между отдельными видами лейкоцитов, появление белков острой фазы, снижение количества Т-хелперных и Т-супрессорных иммунокомпетентных клеток. Подобные изменения иммунных реакций организма человека, по мнению автора статьи, есть результат неконтролируемой гиперпродукции цитокинов, повлиявшей на иммунную реактивность и резистентность организма, а также вызвавшей последующее снижение синтеза специфических антител и ограничение гуморального ответа на антиген. В заключение сделан вывод о необходимости своевременного устранения дисрегуляторного иммунного ответа для формирования адекватного гуморального ответа и сохранения высокой иммунной реактивности организма в человеческих популяциях, а также для повышения резистентности организма и формирования стойкого популяционного иммунитета.