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Introduction. The study of the mechanisms of transmission of the SARS-CoV-2 virus is the basis for building a strategy for anti-epidemic measures in the context of the COVID-19 pandemic. Understanding in what time frame a patient can spread SARS-CoV-2 is just as important as knowing the transmission mechanisms themselves. This information is necessary to develop effective measures to prevent infection by breaking the chains of transmission of the virus. The aim of the work is to identify the infectious SARS-CoV-2 virus in patient samples in the course of the disease and to determine the duration of virus shedding in patients with varying severity of COVID-19. Materials and methods. In patients included in the study, biomaterial (nasopharyngeal swabs) was subjected to analysis by quantitative RT-PCR and virological determination of infectivity of the virus. Results. We have determined the timeframe of maintaining the infectivity of the virus in patients hospitalized with severe and moderate COVID-19. Based on the results of the study, we made an analysis of the relationship between the amount of detected SARS-CoV-2 RNA and the infectivity of the virus in vitro in patients with COVID-19. The median time of the infectious virus shedding was 8 days. In addition, a comparative analysis of different protocols for the detection of the viral RNA in relation to the identification of the infectious virus was carried out. Conclusion. The obtained data make it possible to assess the dynamics of SARS-CoV-2 detection and viral load in patients with COVID-19 and indicate the significance of these parameters for the subsequent spread of the virus and the organization of preventive measures.

Objective. Data of the clinical picture forms of the disease, management and diagnostic capabilities of patients with COVID-19 continue to be studied. Our study presents results from the analysis of clinical and laboratory parameters of patients with COVID-19 in the period May-June 2020, who were treated in an infectious diseases hospital in Moscow. Patients and methods. The analytical cohort included 444, 198 men, 246 women aged 18 to 95 years, who were identified with SARS-CoV-2 RNA. The severity of the disease was determined in accordance with the temporary clinical recommendations (version 6 effective April 28, 2020), NEWS. Results. The study of the clinical picture showed the variability of the spectrum of clinical manifestations of COVID-19. The most common symptoms were fever, weakness, myalgia, dry cough, shortness of breath, diarrhea. The severity of the infection was not associated with the patient's gender, but was significantly correlated with age and the presence of comorbid status, which included chronic lung diseases, obesity, diabetes mellitus, and cardiovascular diseases. Observations of patients with severe and extremely severe course revealed characteristic laboratory markers of severity. The main method of etiological diagnosis was the RT-PCR method for detecting SARS-CoV-2 RNA in the nasopharyngeal secret. To verify COVID-19, we used an additional PCR method, fecal testing for the detection of SARS-CoV-2 RNA. Key words: COVID-19, clinical features, risk factors, SARS-CoV-2 RNA, biological substrates

Whereas the XX century marked the history of acute respiratory disease investigation as a period for generating in-depth system of combating influenza viruses (Articulavirales: Orthomyxoviridae, Alpha-/Betainfluenzavirus) (based on environmental and virological monitoring of influenza A virus in its natural reservoir — aquatic and semi-aquatic birds — to supervising epidemic influenza), a similar system is necessary to build up in the XXI century with regard to especially dangerous betacoronaviruses (Nidovirales: Coronaviridae, Betacoronavirus): Severe acute respiratory syndrome-related coronavirus (SARS-CoV) (subgenus Sarbecovirus), Severe acute respiratory syndrome-related coronavirus 2 (SARSCoV-2) (Sarbecovirus), Middle East respiratory syndrome-related coronavirus (MERS-CoV) (Merbecovirus). This became particularly evident after pandemic potential has been revealed in 2020 by the SARS-CoV-2. This review provides an insight into the historic timeline of discovering this virus, its current taxonomy, ecology, virion morphology, life cycle, molecular biology, pathogenesis and clinical picture of the etiologically related COVID-19 (Coronavirus disease 2019) as well as data available in the scientific literature on the anti-SARS-CoV-2-effectiveness of passive immunotherapy and most debated drugs used to treat COVID-19: Chloroquine, Hydroxychloroquine, Nitazoxanide, Ivermectin, Lopinavir and Ritonavir, Camostat mesilate, Remdesivir, Ribavirin, Tocilizumab, Anakinra, corticosteroids, and type I interferons. The pathogenesis of SARS-CoV-2 infection implicates decreased efficacy of artificial respiration, which, in this case might be replaced by more efficient extracorporeal membrane blood oxygenation supplemented with nitrogen oxide and/or Heliox inhalations.

Since the beginning of the 2021 year, all the main six vaccines against COVID-19 have been used in mass vaccination companies around the world. Virus neutralization and epidemiological efficacy drop obtained for several vaccines against the B.1.1.7, B.1.351 P.1, and B.1.617 genotypes are of concern. There is a growing number of reports on mutations in receptor-binding domain (RBD) increasing the transmissibility of the virus and escaping the neutralizing effect of antibodies. The Sputnik V vaccine is currently approved for use in more than 66 countries but its activity against variants of concern (VOC) is not extensively studied yet. Virus-neutralizing activity (VNA) of sera obtained from people vaccinated with Sputnik V in relation to internationally relevant genetic lineages B.1.1.7, B.1.351, P.1, B.1.617.2, B.1.617.3 and Moscow endemic variants B.1.1.141 (T385I) and B.1.1.317 (S477N, A522S) with mutations in the RBD domain has been assessed. The data obtained indicate no significant differences in VNA against B.1.1.7, B.1.617.3 and local genetic lineages B.1.1.141 (T385I), B.1.1.317 (S477N, A522S) with RBD mutations. For the B.1.351, P.1, and B.1.617.2 statistically significant 3.1-, 2.8-, and 2.5-fold, respectively, VNA reduction was observed. Notably, this decrease is lower than that reported in publications for other vaccines. However, a direct comparative study is necessary for a conclusion. Thus, sera from “Sputnik V”-vaccinated retain neutralizing activity against VOC B.1.1.7, B.1.351, P.1, B.1.617.2, B.1.617.3 as well as local genetic lineages B.1.1.141 and B.1.1.317 circulating in Moscow.