On the association between the ABO blood group and COVID-19 susceptibility

Dear Sir, At present, the evidence of the influence of ABO polymorphism on host susceptibility to SARS-CoV-2 infection is still preliminary. However, the study by Muñiz-Diaz et al.1 fits into a context of recent studies2-4 confirming that blood group A is associated with an increased risk of SARS-CoV-2 infection, while blood group 0 reduces one’s risk of becoming positive. It also confirms what was seen for SARS-CoV in 20034. However, there appears to be a need to further develop these findings through in-depth studies into the mechanisms that form the basis for this association. Is it related to some tied network of ACE2 receptor upregulation in people who have blood group A? Or is it related to the anti-A and anti-B antibodies in blood group 0 individuals that circulate at high concentrations? [ …