Table 2.

Risk of SARS-CoV-2 infection amongst blood groups in cohort studies and in cross-sectional studies.

Study	Blood Group A		Blood Group B		Blood Group AB		Blood Group O		Overall
	Risk	Pos./Tot.	Risk	Pos./Tot.	Risk	Pos./Tot.	Risk	Pos./Tot.	Risk
Ahmed et al., 2021 [26]	27.0%	34/126	28.4%	19/67	41.4%	12/29	15.8%	21/133	24.2%
Barnkob et al., 2020 [27]	1.6%	3296/202,507	1.7%	897/53,735	1.8%	378/21,160	1.5%	2851/196,252	1.6%
Boudin et al., 2020 [28]	77.3%	521/674	73.8%	135/183	77.1%	54/70	74.5%	553/742	75.7%
Coluk et al., 2021 [29]	68.3%	69/101	62.5%	20/32	55.6%	5/9	72.5%	50/69	68.2%
Haizler-Cohen et al., 2021 [30]	15.2%	145/955	14.2%	72/508	14.9%	22/148	15.8%	209/1319	15.3%
Horspool et al., 2021 [31]	17.4%	4/23	22.2%	2/9	0.0%	0/2	13.3%	4/30	15.6%
Ibrahim et al., 2021 [32]	10.2%	18/176	8.0%	7/88	6.3%	1/16	13.1%	40/306	11.3%
Khosroshahi et al., 2021 [33]	9.3%	21/225	6.9%	11/160	0.0%	0/52	5.2%	12/233	6.6%
Latz et al., 2020 [35]	16.6%	440/2649	19.4%	201/1035	19.8%	61/308	16.1%	587/3656	16.9%
Lehrer et al., 2021 [36]	5.9%	323/5516	5.3%	66/1238	5.3%	23/431	5.7%	308/5390	5.7%
Levi et al., 2021 [37]	32.6%	816/2505	33.2%	237/713	30.0%	71/237	30.4%	913/3002	31.5%
Mahallawi et al., 2021 [38]	29.2%	117/401	12.6%	32/253	16.4%	9/55	15.1%	76/503	19.3%
Niles et al., 2020 [39]	11.8%	11,017/93,750	11.8%	4282/36,140	11.4%	1153/10,133	13.0%	17,739/136,513	12.4%
Quiroga et al., 2021 [40]	21.9%	34/155	15.2%	5/33	25.0%	2/8	15.3%	19/124	18.8%
Ray et al., 2021 [41]	3.0%	2420/81,797	4.1%	1378/33,536	3.8%	390/10,221	2.9%	2883/100,002	3.1%
Schetelig et al., 2021 [42]	5.3%	2345/44,131	4.8%	570/11,866	5.3%	285/5370	4.7%	1916/40,975	5.0%
Zhang et al., 2021 [43]	9.4%	728/7744	10.0%	177/1763	9.1%	56/613	9.1%	682/7466	9.3%

Notes: Pos. = individuals positive for SARS-CoV-2; Tot. = total number of individuals tested for SARS-CoV-2.