Variability in the Clinical Course of COVID-19 in a Retrospective Analysis of a Large Real-World Database
Robert Flisiak,
Piotr Rzymski,
Dorota Zarębska-Michaluk,
Przemysław Ciechanowski,
Krystyna Dobrowolska,
Magdalena Rogalska,
Jerzy Jaroszewicz,
Anna Szymanek-Pasternak,
Marta Rorat,
Dorota Kozielewicz,
Justyna Kowalska,
Ewa Dutkiewicz,
Katarzyna Sikorska,
Anna Moniuszko-Malinowska
Affiliations
Robert Flisiak
Department of Infectious Diseases and Hepatology, Medical University of Białystok, 15-540 Białystok, Poland
Piotr Rzymski
Department of Environmental Medicine, Poznan University of Medical Sciences, 60-806 Poznań, Poland
Dorota Zarębska-Michaluk
Department of Infectious Diseases, Jan Kochanowski University, 25-317 Kielce, Poland
Przemysław Ciechanowski
Department of Paediatrics and Infectious Diseases, Regional Hospital in Szczecin, 71-455 Szczecin, Poland
Krystyna Dobrowolska
Collegium Medicum, Jan Kochanowski University, 25-317 Kielce, Poland
Magdalena Rogalska
Department of Infectious Diseases and Hepatology, Medical University of Białystok, 15-540 Białystok, Poland
Jerzy Jaroszewicz
Department of Infectious Diseases and Hepatology, Medical University of Silesia in Katowice, 41-902 Bytom, Poland
Anna Szymanek-Pasternak
Department of Infectious Diseases and Hepatology, Wrocław Medical University, 51-149 Wrocław, Poland
Marta Rorat
Department of Forensic Medicine, Wrocław Medical University, 50-367 Wroclaw, Poland
Dorota Kozielewicz
Department of Infectious Diseases and Hepatology, Faculty of Medicine, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 87-100 Torun, Poland
Justyna Kowalska
Department of Adult’s Infectious Diseases, Medical University of Warsaw, Hospital for Infectious Diseases, 02-091 Warsaw, Poland
Ewa Dutkiewicz
Collegium Medicum, Jan Kochanowski University, 25-317 Kielce, Poland
Katarzyna Sikorska
Division of Tropical and Parasitic Diseases, Faculty of Health Sciences, Medical University of Gdańsk, 80-210 Gdańsk, Poland
Anna Moniuszko-Malinowska
Department of Infectious Diseases and Neuroinfections, Medical University of Białystok, 15-809 Bialystok, Poland
The COVID-19 pandemic proceeds in waves, with variable characteristics of the clinical picture resulting from the evolution of the SARS-CoV-2 virus. This study aimed to compare the epidemiological characteristics, symptomatology, and outcomes of the disease in patients hospitalized for COVID-19 during periods of different variants dominance. Comparing the periods of dominance of variants preceding the Delta variant, the Delta period was characterized by a higher share of hospitalized females, less frequent comorbidities among patients, and a different age distribution. The lowest need for oxygen therapy and mechanical ventilation was observed under Omicron dominance. The triad of classic COVID-19 symptoms, cough, fever, dyspnoea, and fatigue, were most prevalent during the Delta period, and significantly less common under the Omicron dominance. During the Omicron period, nearly twice as many patients as in the previous periods could be discharged from the hospital within 7 days; the overall 28-day mortality was significantly lower compared to that of the Delta period. It also did not differ between periods that were dominated by the BA.1 and BA.2 subvariants. The study indicates that the Omicron SARS-CoV-2 variant that dominated between January and June 2022 caused a disease which resembled the common cold, and was caused by seasonal alpha and beta-coronaviruses with a low pathogenicity for humans. However, one should note that this effect may not only have been related to biological features of the Omicron lineage, but may additionally have been driven by the increased levels of immunization through natural infections and vaccinations, for which we could not account for due to a lack of sufficient data.
