Currently, the intensity of COVID-19 epidemic in Russia is declining. Most of the country’s regions are at the first stage of lifting restrictions; some regions have moved to the second and third phases. At the same time, the development of the COVID-19 pandemic in Southern hemisphere indicates the continuous circulation of SARS-CoV-2 in the world. The article provides statements arguing for the development of the «second wave» of the COVID-19 epidemic in Russia, as well as practical recommendations aimed at preparing for the autumn-winter epidemic season 2020–2021.

The work objective was to carry out the analysis of the existing in the Russian Federation monitoring of the incidence of new coronavirus infection in children and specific features of death cases caused by COVID-19 in children.
Materials and methods. The analysis of the data of operative statistics presented on the sites of the governments of the regions where the incidence among children was considered within the period from April 22, 2020 to June 26, 2020, as well as the data of the Main non-staff experts in infectious diseases in children was performed. The inpatient medical documentation and the data of pathologicoanatomic investigation of children died due to COVID-19 were analyzed.
Results. Prevalence of COVID-19 in children from various regions of the Russian Federation was from 1% to 8.6% in the structure of general disease incidence. The asymptomatic and mild forms of the disease which did not require hospitalization, were noted in 55–60% of the cases. 12 death cases associated with COVID-19 were registered for June 22, 2020. The analysis of 8 presented cases showed that 6 patients out of 8 died children were of the first half of the year of life (3 girls and 5 boys). In most cases the children were admitted to the hospital at the 8–12th day of the disease in severe and extremely severe condition due to pulmonary-cardiac insufficiency, six patients had fever up to 38–39°С, four patients had signs of consciousness depression. All children were diagnosed with community-acquired bilateral pneumonia according to the data of roentgenography, ultrasound investigation or computer tomography of the chest organs that did not always coincide with the intensity of respiratory syndrome. The direct cause of death was cardiac or pulmonary-cardiac insufficiency.
Conclusion. The analysis of clinical and laboratory manifestations of COVID-19 with an unfavourable outcome in children revealed some difficulties in the interpretation of its role in thanatogenesis. The significance of comorbid pathologies in the development of unfavourable outcomes is doubtless.

Recently, vitamin D deficiency is considered as a risk factor for the incidence and severity of new coronavirus infection.
The aim of this work was to evaluate the vitamin D level of patients with COVID-19 hospitalized with communityacquired pneumonia and compare the value of 25(OH)D in blood serum with the clinical manifestations of the disease.
Results. Included are 80 patients aged 18 to 94 years (mean age 53,2 ± 15,7 years), 43 (53,8%) men; with severe course – in 25 (31,3%) patients (12 males), and moderate – in 55 people (68,7%) (31 males). Half of the severely ill patients were obese, and among the deceased patients, the number of obese people was 61,5%, which was significantly higher than the discharged ones – 14,9% (p<0,001). Diabetes mellitus and cardiovascular diseases occurred with the same frequency, regardless of the severity of the disease. Analysis of the outcomes of coronavirus infection in these patients showed mortality in 52,0% of cases in severe patients. Serum 25(OH)D level ranged from 3,0 to 88,8 ng / ml (16,7 ± 12,7 ng / ml). It was found that in patients with severe course, the level of 25(OH)D blood was significantly lower (11.9 ± 6.4 ng / ml) and vitamin D deficiency was more common than in patients with moderate to severe course of the disease (18,5 ± 14,0 ng / ml, p = 0,027). The same pattern was revealed in patients with a fatal outcome, where the level of 25(OH)D was 10,8 ± 6,1 ng / ml, compared with this indicator in patients discharged from the hospital (17,8 ± 13,4 ng / ml) (p = 0,02).
Conclusions. Vitamin D deficiency and obesity have been found to increase the risk of severe course and death of coronavirus infection.

The new coronavirus infection (COVID-19) has become a truly global challenge for all of humanity, and, above all, for the healthcare system. Among its most important aspects requiring careful analysis are the clinical and laboratory features of the course of the disease, which make it possible to determine approaches to pathogenetic therapy in severe forms of the disease.
Materials and methods. A retrospective analysis of medical records of patients (n = 31) of severe COVID-19 patients who were hospitalized in St. Petersburg City Clinical Hospital for Infectious Diseases named after S.P. Botkin ”in March – May 2020. Clinical and laboratory characteristics were evaluated, including the level of ferritin, C-reactive protein, D-dimer, interleukin-6, depending on the severity of the disease. The criteria for the appointment of a recombinant humanized monoclonal antibody to the human receptor for interleukin-6 (INN – tocilizumab) in patients with a severe course of the disease and its effectiveness are determined.
Results. In the treatment of severe patients with COVID-19, it is necessary to carefully evaluate the clinical picture of the course of the disease, which may be ahead of changes in laboratory parameters. The introduction of tocilizumab leads to a rapid regression of general infectious symptoms, subjective and objective manifestations of respiratory failure and, as a consequence, a decrease in the duration of hospitalization. It is extremely important that the drug is administered in a timely manner during the rise of the “cytokine storm”. The time for optimal administration of tocilizumab begins from 8-9 days from the onset of the disease, until the patient is transferred to mechanical ventilation.

Aim. In this study we evaluated clinical effectiveness and safety of nebulized prostacyclin in patients with Novel Coronavirus Disease (SARS-CoV-2).
Materials and methods: We have included 44 male patients with moderate PCR confirmed SARS-CoV-2 infection in this study. Control group consisted of 23 patients treated with nebulized prostacyclin (PGI₂). besides standard therapy. We compared intensiveness and duration of infectious intoxication syndrome, duration of fever, cough as well as SpO₂ level, complete blood count and chemokine status values.
Results: Statistically significant difference in duration of fever, cough, intensiveness and duration of infectious intoxication syndrome were observed. Lymphocyte and platelet counts were significantly higher in control group We have also noticed significantly lower level of proinflammatory mediators and C4-complement component in control group. Only 1 adverse effect associated with inhaled prostacyclin was reported.
Conclusion. Nebulized prostacyclin showed therapeutic efficacy and good safety profile in adults with moderate COVID-19.

Objective: isolation of coronavirus SARS-CoV-2 from clinical sample of patient with COVID-19 in Novosibirsk; obtaining a purified and inactivated viral antigen and study of its antigenic properties. Materials and methods: virus isolation was carried out in Vero cell culture from nasopharyngeal swab positive on SARS-CoV-2 RNA. The efficiency of SARSCoV-2 replication in cell culture was assessed on the appearance of cytopathic effect (CPE) and the presence of viral RNA in cultural medium with reverse transcription – polymerase chain reaction (RT-PCR). Purification, concentration and inactivation of the viral preparation were carried out according to standard methods. The purity of the purified preparation and the profile of viral proteins were determined by electrophoresis in 10% polyacrylamide gel (PAG) with the addition of sodium dodecyl sulfate (SDS). The presence and specificity of viral proteins were detected using COVID-19 convalescent’s sera with enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Results: SARS-CoV-2/human/ RUS/Nsk-FRCFTM-1/2020 isolate was obtained after passage on Vero cells from a virus-containing clinical sample. A purified, concentrated, inactivated, whole-virion antigen was obtained. It contains three structural proteins: glycoprotein S (approximately 200 kDa), nucleoprotein N (48 kDa), and matrix protein M (20-25 kDa). All viral proteins were detected with serum antibodies of COVID-19 convalescents.
Conclusion: SARS-CoV-2 coronavirus can be isolated in Vero cell culture. The antigenic specificity of the three structural viral proteins (S, N, and M) is preserved in the purified inactivated viral preparation. The inactivated whole-virion antigen of SARS-CoV-2/human/RUS/Nsk-FRCFTM-1/2020 isolate can be used to study the antigenic immunomodulating properties of viral proteins, to obtain immune sera of laboratory animals, and also as a component of test systems for the detection of specific antibodies with ELISA and immunoblotting.

Among the problems associated with a new coronavirus infection, the possibility of its occurrence in pregnant women plays an important role. Until now, there is very little data on perinatal COVID-19, and there are no descriptions of structural changes in the afterbirth at all.
Material and methods. A clinical and morphological analysis of 6 cases in which women with verified COVID-19 gave birth in an infectious hospital was performed. In all cases, the placenta was examined in detail morphologically using antibodies to the nucleoprotein and spike (S1 subunit spike protein) SARS-CoV-2. COVID-19
Results. It is shown that the clinical course of COVID-19 in pregnant women may be different, three were in the intensive care unit, including one was shown to be on a ventilator. 4 children were born at term, 2 children prematurely (at 31- 33 weeks of pregnancy). The condition of children in 5 nab. was assessed as satisfactory, only one child in serious condition was transferred to a children’s hospital. Intrauterine infection with the polymerase chain reaction documented in a single observation. When histological examination of the afterbirth in all observations, both in the maternal and fetal parts, changes characteristic of RNA viral infection was detected. Both of the studied antigens were found in moderate amounts in IHC.
Conclusions. Intrauterine transplacental infection with a new coronavirus is certainly possible. Its frequency and clinical significance require further comprehensive study.

Objective: to identify the clinical, laboratory and epidemiological features of the new coronavirus (CV) infection in the provision of specialized medical care to children in the megalopolis of the Russian Federation.
Methods: 674 cases of hospitalization of patients from birth to 17 years old inclusive with confirmed COVID-19 in the period from March 26 to June 26, 2020 in a children’s multidisciplinary hospital in St. Petersburg. Diagnostics of SARS-COV-2 in upper respiratory tract (URT) smears was carried out by PCR (a set of reagents for detecting RNA of coronavirus 2019-nCoV by PCR with hybridization-fluorescence detection “Vector-PCRRV-2019-nCoV-RG”). Patients underwent 4 (3; 5) repeated examinations depending on the diagnosis of the referral, as well as the duration of the convalescent virus carriage. The analysis of the severity of the course of the disease, the main clinical manifestations and their relationship with the development of pneumonia, as well as the epidemiological features of COVID-19 in children. The duration of inpatient treatment, outcomes and the need for intensive care are described. Changes in a number of laboratory parameters on analyzers made in the USA were assessed: a clinical blood test on a hematological one - Coulter UniCel (Beckman Coulter), a biochemical blood test on a biochemical one - Uni Cel DxC (Beckman Coulter), a coagulogram on a hemostasis analyzer (Instrumentation Laboratory).
Results: Overall, there was a favorable course of COVID-19 in children. Intensive therapy was required only in 3.6% of cases with a total mortality rate of 0.15%, Kawasakilike syndrome was recorded in 0.3% of cases. In 1/3 of patients, prolonged viral shedding from the upper respiratory tract was detected. In children, intrafamilial infection from adults was in the lead; schoolchildren accounted for half of all hospitalizations. A distinctive feature of the new infection was mild clinical symptoms with fever and catarrhal symptoms up to 4/5 of cases, gastrointestinal symptoms - in every third patient. There were no significant differences in the severity of the disease by age. Pneumonia, diagnosed in ¾ cases by computed tomography, complicated the course in 13.1% of cases. The defeat of the lungs was accompanied by fever and dry cough, and in a more severe course: desaturation, chest pains, a feeling of insufficiency of inspiration. The age peaks of the incidence of pneumonia were revealed: at 4, 9, 12 years old and at the age of 17 years, the maximum (in 1/3 of cases). Laboratory changes were insignificant and quickly reversible.
Conclusion: the course of COVID-19 in children in the megalopolis of Russia is comparable with foreign information. However, taking into account the experience of “Spanish ‘flu”, it is possible that in pediatric practice the number of severe forms and unfavorable outcomes may change in the near future, especially due to the difficulty of diagnosing Kawasaki-like syndrome and the need for a multidisciplinary approach to the treatment of such patients. Currently, the most vulnerable to the new CV are children with severe oncological, neurological and cardiovascular pathology, who have a rapid decompensation of the underlying disease against the background of COVID-19.

The review presents current literature data on the medical rehabilitation of children undergoing COVID-19. The clinical features and leading syndromes of COVID-19 in children, as well as primary lesions of organs and systems requiring the use of medical rehabilitation methods, are considered. Rehabilitation technologies are proposed depending on the leading clinical syndrome. Information on the main rehabilitation technologies used in children with the consequences of COVID-19 is necessary for the implementation of comprehensive medical rehabilitation at all stages of treatment and recovery.

Currently, there is little data on the effect of coronavirus infection COVID-19 on pregnancy, childbirth, the condition of the fetus, and the postpartum period. The article describes a clinical case of severe coronavirus infection of COVID-19 in a pregnant patient, with the rapid development of acute respiratory distress syndrome.

The risk of a severe course of new coronavirus infection (COVID-19) due to the development of acute respiratory distress syndrome is extremely high, which is especially true for patients with comorbidities.
The aim of the study is to demonstrate the peculiarities of the course and intensive care measures in new coronavirus infection COVID-19 in children with comorbidities.
Patients and methods: On the example of clinical cases, the characteristics of the course of a new coronavirus infection of COVID-19 in children with systemic lupus erythematosus and bronchopulmonary dysplasia are considered.
Results: The main data from the history and clinical laboratory examination are reflected, which made it possible to identify a cytokine storm in a timely manner, a high risk of adverse course and begin timely specific pathogenetic therapy, including immunoglobulins for intravenous administration, hydroxychloroquine, ritonavir in combination with lopinavir, azithromycin and dexamethasone. Particular attention is paid to the need to limit infusion therapy, maintain a negative water balance and optimal blood oxygen capacity, ambiguity of opinions on the need for routine use of albumin and dexamethasone solutions in patients with COVID-19 has been demonstrated.
Conclusion: Children with comorbidities are characterized by a severe course of a new coronavirus infection COVID-19, which requires timely pathogenetic therapy taking into account the individual characteristics of the patient.

Improving the approaches to treating COVID-19 infection opens up the possibility for using previously known groups of drugs that demonstrate their effectiveness in the pathogenetic treatment of this disease.
Significant clinical experience in the field of treatment of COVID-19 have been accumulated in Clinical Infectious Diseases Hospital named after S.P. Botkin, Saint-Petersburg, Russia. The case study demonstrates the timeliness and effectiveness of anticytokine therapy with COVID-19, the possibility of using a recombinant humanized monoclonal antibody to the human receptor for interleukin-6 (IL-6) (tocilizumab).

Coronavirus infection (COVID-19) is an acute infectious disease caused by a new strain of the virus of the genus coronavirus SARS-CoV-2 with the aerosol-droplet and contact-household transmission mechanism; patogenetically local and systemic inflammatory process, hyperactive impulsive cascade, endotheliopathy, hypoxia, leading to the development of micro – and microthrombosis; it occurs from asymptomatic to clinically significant forms of intoxication, vascular lesions, lungs, heart, kidneys, and GI tract with risk of complications (ARF, ARDS, sepsis, shock, multiple organ dysfunction SYNDROME, pulmonary embolism).
Currently, there are few data on the course of this disease in patients undergoing treatment with program hemodialysis, as well as methods of specific treatment of this group of patients.
The article describes the case of the first patient in the Clinical Infectious Hospital named after S.P. Botkin with end-stage chronic kidney disease corrected by program hemodialysis, who had a COVID-19.