The effect of ABO blood group and antibody class on the risk of COVID-19 infection and severity of clinical outcomes.

AlMadhi, M.; Abdulrahman, A.; AlAwadhi, A.; Rabaan, A.; AlQahtani, M.

The current COVID-19 pandemic has affected more than 22 million cases and caused immense burdens on governments and healthcare systems worldwide. Since its emergence in December 2019, research has been focused on ways to not only treat the infected but also identify those at risk and prevent spread. There is currently no known biological biomarker that can predict the risk of being infected. A growing set of studies have emerged that show an association between ABO blood group and the risk of COVID-19 infection. In this study, we used retrospective observational data in Bahrain to investigate the association between ABO blood group and risk of infection as well as susceptibility to a more severe ICU-requiring infection. We found that individuals with blood group B were at a higher risk of infection, while those with blood group AB were at a lower risk. No association was observed between blood group and the risk of a severe ICU-requiring COVID-19 infection. We extended the analysis to study the association by antibodies present; anti-a (blood groups B and O) and anti-b (blood groups A and O). Antibodies were not found to be associated with either risk of infection or susceptibility to severe infection. The current study, along with the variation in blood group association results, indicates that blood group may not be the most ideal biomarker to predict risk of COVID-19 infection.