Table 3.

Results of the severity analysis.

First author, Year	Severe		Non-severe		Severe		Non-severe		Severe		Non-severe		Severe		Non-severe
	A	Non-A	A	Non-A	B	Non-B	B	Non-B	AB	Non-AB	AB	Non-AB	O	Non-O	O	Non-O
Xianfei Zeng, 2020	40	57	54	83	30	67	34	103	0	97	0	137	27	70	49	88
Michael Zietz 2020	62	117	144	279	35	144	69	354	8	171	8	415	74	105	202	221
Xiang Tianxin, 2020	3	2	19	21	1	4	10	30	0	5	1	39	1	4	10	30