This study aims to identify the features of clinical and immunological signs accompanying pathological changes caused by COVID-19 in moderate and severe diseases. To identify complications of acute respiratory disease caused by SARS-CoV-2, detected at autopsy. Retrospective analysis of the results of immunological and microbiological studies of 20 patients with confirmed SARS-CoV-2 infection who were treated in clinics of the city of Sumy in 2020-2021: Group 1: 25.0% with severe disease (mean age 62.1±2.1 years); Group 2: 75.0% with mild or asymptomatic disease (43.0±0.9 years). Analysis of 20 autopsy reports and inpatient medical records for deceased patients for the period from December 2020 to June 2021. The main morphological, clinical, and immunological changes detected in both groups are described, the changes in the body for acute respiratory viral infection SARS-CoV-2 in mild and severe forms of the disease are analyzed. The results of autopsies in severe COVID-19 that resulted in death are presented. The rapid spread of SARS-CoV-2 is caused by the antigenic variability of viruses under the influence of immune factors in the body of previously infected people and is associated with defects in the organization of medical care in medical institutions of the region and Ukraine as a whole, as well as with underfunding of the medical sector and health care.