Apart from demographic and epidemiological risk factors, the role played by biological markers has been studied.12-14 Of late, ABO blood type and Rhesus status have been suggested as a cause for variable predisposition to COVID-19.15 Studies on the relationship of ABO/Rh-D blood types with SARS-CoV-2 infection are not consistent in their findings, and researchers have not arrived at a plausible explanation for their results. The gene discussed is ABO; the disease is COVID-19.