“…Nonetheless, blood type A has been the most associated with severe outcomes, while blood type O frequently appears as a protective factor against the disease progression [ 17 , 18 , 69 , 70 , 77 , [83] , [84] , [85] , [86] , [87] , [88] ]. For instance, although failing to describe a significant difference in ABO phenotype distribution between hospitalized COVID-19 patients and the control group, Muñiz-Diaz et al described a significant positive association between blood type A and mortality, and a significant negative association for blood type O [ 18 ].…”