While previous studies (Table III in supporting information) (Rowe et al, 2007; Fry et al, 2008) have suggested an association between ABO and severity, we document for the first time an increased odds ratio of death associated with A or AB types, providing clinical evidence to substantiate malaria as an evolutionary driver of human ABO blood group distributions (Cserti & Dzik, 2007). The gene discussed is ABO; the disease is malaria.