Demographic and Clinical characteristics of study participants
A total of 125 admitted hospital patients, laboratory-confirmed positive for SARS-CoV-2 infection by quantitative RT-PCR of throat and nasal swab samples were recruited for the study. According to the clinical management protocol for COVID-19 (Version 3) issued by Ministry of Health and Family Welfare, Government of India, patients were recruited into different groups based on clinical severity(7). The patients without evidence of breathlessness or hypoxia were classified into Mild group. Mild patients were further segregated into Asymptomatic Mild (AM; n=47) and Symptomatic Mild (SM; n=57) where SMs presented mild symptoms like fever, cough, sore throat, headache etc. Patients with oxygen saturation (SpO2) of < 93% on room air who required oxygen support to correct hypoxemia, were classified as having Moderate (MD; n=10) COVID-19, whereas patients with oxygen saturation (SpO2) of < 90% on room air were considered as having Severe (SV; n=11) COVID-19. In addition, a total of 16 healthy participants with no apparent history of COVID-19 and seronegative (SN) by Rapid antibody test, were also recruited as controls. The demographic and clinical characteristics of all the study participants is summarised in Table 1.