ABO Phenotype and Death in Critically Ill Patients with COVID-19.

Blood groups are inherited traits that vary across populations, likely due to both founder effects and natural selection. A link between blood groups and susceptibility to infectious disease has been well-described, with notable examples being H. Pylori and Plasmodium falciparum infection. Blood group antigens may influence disease susceptibility by several mechanisms, including serving as receptors or decoys for infectious organisms and modifying immune response in the form of anti-ABO antibodies.