ABO and malaria: This increased the strength of the evidence that HBB, ABO, HBA1-2, and FREM3/GYP are associated with protection against severe malaria compared with the non-weighted case–controls odds-ratios (for HBA1-2: p = 10−5 versus p = 10−4; ABO: p = 10−13 versus p = 10−8; FREM3: p = 10−12 versus p = 10−11).