Positive QuantiFERON test and the severity of COVID-19 disease: A prospective study

•A prospective comparative study comprising of 3 groups of 20 subjects each.•Group A was asymptomatic, S-Severely ill COVID-19 patients and H- Healthy volunteers.•QuantiFERON TB Gold (QFT) showed strong negative correlation with COVID-19 mortality.•Positive QFT was seen in 15% patients only of Group S against 50% in group A and H.•BCG scar showed no correlation with prevalence or progression of the disease.