At the Teaching Hospital-Karapitiya.This study mainly aims to identify biomarkers of severe COVID-19 and to determine the prevalence of dengue false-positive IgM in COVID-19 patients. The principal investigators of the study are Prof. Gaya Wijayaratne (professor in Microbiology, Faculty of Medicine, University of Ruhuna), Dr. Gayani Tillekeratne (Associate Professor in Medicine, Duke University, USA), and Prof. Ashley Lauren St. John (Duke-NUS Medical School, Singapore). Co-investigators of the study: Prof. Ajith Nagahawatte, Prof. Champika Bodinayake (Faculty of Medicine, University of Ruhuna). Data collection was concluded, and data analysis is still in progress.