Table 3.

Summary of reported studies assessing the association between blood groups and SARS‐CoV‐2 infection

Ref. Author (country)	COVID‐19 study population	Controls(if applicable)	% group A patients (vs. control) P value (when applicable)	% group O patients (vs. control) P value (when applicable)	Blood group susceptibility to SARS‐CoV‐2 infection	Association with clinical outcomes and risk of death
Zhao J et al. [5] China	1775 patients	3694 normal individuals	37·75 (32·16) P < 0·001	25·80 (33·84) P < 0·001	Yes, group A	Group A associated with higher risk of mortality than non group A
Li J et al. [7] China	2153 patients with COVID‐19 pneumonia	3694 healthy controls	38·0 (32·2) P < 0·001	25·7 (33·8) P < 0·001	Yes, group A	Group A patients at higher risk of hospitalization following SARS‐CoV‐2 infection. Association with risk of mortality not assessed.
Zeng X. et al. [51] China	137 patients with mild pneumonia 97 patients with severe pneumonia	Nil, Chinese population data used for comparison	35·76 (28·39) 39·22 (28·39)	32·45 (33·20) 26·47(33·20)	Yes, group A	Blood group A more susceptible to SARS‐CoV‐2. Blood groups not relevant to acute respiratory distress syndrome, acute kidney injury and mortality.
Zietz M & Tatonetti [56] USA	Observational data on 14,112 individuals tested for SARS‐CoV‐2	None	32·7 (32·7)	46·9 (48·2)	Yes, group B and Rh(D)	Risk of intubation decreased among group A and increased among groups AB and B. Risk of morality increased for group AB and decreased for groups A and B. Rh‐negative blood type protective for mortality.
GÖKER H, et al . [49] Turkey	186 patients	1881 healthy controls	57 (38) P < 0·001	24·8 (37·2) P = 0·001	Yes, group A	No significant effect of ABO and RhD on clinical outcomes including intubation, ICU stay and mortality
Wu et al. [52] China	187 patients	1991 non‐COVID‐19 hospitalized patients	36·9 (27·47) P = 0·006	21·92(30·19) P = 0·018	Yes, group A	Group A influenced clinical outcomes but no association with mortality
Leaf RK et al. [48] USA	561 critically ill patients.	Nil, local population data used for comparison	45·1 (39·8)	37·8 (45·2)	Yes, group A	No association with any ABO phenotype and mortality
Latz CA et al. [6] USA	1289 patients	Nil	34·2 (NA)	45·5 (NA)	Yes, positive correlation with group B , AB & Rh(D)Negative with group O	No association with risk of intubation, peak of inflammatory markers and death
Gerard C et al. [12]	1175 patients	3694 controls	37·7 (32·2) P < 0·001	49·4 (57·6)	Yes, presence of anti‐A antibodies in serum and more specifically IgG anti‐Aassociated with higher susceptibility to SARS‐CoV‐2 infection.	Mortality risk not assessed
Abdollahi A et al. [50] Iran	397 patients	500 normal controls	40·3 (36) P = 0·19	28 (38) P = 0·002	Yes, group AB with higher susceptibility than other groups.	No association of ABO or RHD phenotype with severity of disease. No association of ABO or RHD with mortality assessed.
Hoiland et al. [4] Canada	125 critically ill patients admitted to ICU	Nil, Comparison of blood group distributions between blood donor data was performed.	37 (35) p‐0·60 No difference from blood donors	Group O 43% (n = 41) No difference from blood donors	Yes, group A and AB	Higher proportion of COVID‐19 patients with blood group A or AB required mechanical ventilation, and continous renal replacement therapy and had longer ICU stay compared with patients with blood group O or B.
Barnkob et al. [3] Denmark	7422 COVID positive patients among 473 654 individuals tested	466 232 COVID‐negative individuals	More A (P <0·001), B (P = 0·011), and AB (P = 0·091) individuals were COVID positive.	38·41% (95% CI, 37·30–39·50) group O compared with 41·70% (41·60–41·80) in controls	Yes, Decreased infection risk in group O	ABO blood group as a risk factor for SARS‐CoV‐2 infection but not for hospitalization or death from COVID‐19.