COVID-19. AETIOLOGY, PATHOGENESIS, DIAGNOSIS AND TREATMENT

Abstract

COVID-19 (Coronavirus disease 2019) is a new epidemic infectious disease characterized by a relatively high contagiousness and a high probability of life-threatening complications such as acute respiratory distress syndrome (ARDS), acute respiratory and multiple organ failure. The causative agent of the disease is the en-veloped zoonotic RNA virus known as SARS-CoV-2. Together with the SARS-CoV and MERS-CoV viruses, which cause severe acute respiratory syndrome and the Middle East respiratory syndrome, respectively, it belongs to the Coronaviridae family, the genus Betacoronavirus. The COVID-19 epidemic has spread rap-idly around the world and currently hit 213 countries with more than 1.6 million confirmed cases, of which more than 90.000 have died so far. In Russian Federation, SARS-CoV-2 infection is included in the list of diseases that pose a danger to others, along with especially dangerous infections. The virus is transmitted by airborne droplets, airborne dust and contact routes, therefore, to protect medical staff it is necessary to use individual protective suits and accessories, with protection of the respiratory tract and eyes, disinfection of hands and surfaces as when working with the BSL-2 microorganisms. The diagnosis of COVID-19 is confirmed using real-time RT-PCR diagnostics detecting the presence of viral RNA. Clinical manifestations of COVID-19 vary from mild and moderate (pneumonia without signs of hypoxemia and impaired O2 saturation, 80% of all cases), to severe (15% of cases, O2 saturation 89–93%) and extremely severe (5% of cases, ARDS, multiple organ failure, mechanical ventilation and resuscitation are necessary). The typical clinical presentation of COVID19 patients includes the following: severe fever, dry cough, respiratory failure, com-bined with lymphopenia and thrombocytopenia, normal procalcitonin, elevated levels of ferritin and CRP in the blood with signs of bilateral, polysegmental pneumonia and the “ground glass” opacity on CT. Even in the absence of an unfavorable epidemiological anamnesis, these clinical signs can be recommended to admit the patient to an infectious isolation ward where he or she would wait for the results of PCR diagnostics and the diagnosis of COVID-19 be confirmed/ ruled out. Currently, no SARS-CoV-2-specific therapy is available for COVID-19 patients; the only method that has proven effective in several investigational trials is transfusion of convalescent plasma with high titers of neutralizing antibodies. A number of innovative treatments appear promising and include the use of neutralizing monoclonal antibodies, ACE2-derived agents, as well as MSC-and NK-cell based cell therapies.