Under co-dominant, recessive, and additive models, the TT (Phe/Phe) genotype of the ABO rs8176740 T/A polymorphism was associated with a high risk of developing COVID-19 (OR = 1.89, 95% CI: 1.23–2.91, pCCo-dominant = 6 × 10−6; OR = 1.98, 95% CI: 1.38–2.62, pCRecessive = 1 × 10−4; and OR = 1.36, 95% CI: 1.11–1.68, pCAdditive = 3 × 10−3, respectively). The gene discussed is ABO; the disease is COVID-19.