ABO and infection: In this context, considering the critical role of the ABO blood groups as the first line of defense against infection and entry of the virus into the host, the present study aimed to establish whether the rs651007 T/C, rs579459 T/C, rs495828 T/G, rs8176746 A/C, rs8176740 T/A, and rs512770 T/C polymorphisms increased the risk of developing COVID-19.