Prevalence of ABO blood types in severe and mild patient groups.

ABO allele frequencies and resultant ABO phenotypes were consistent with known prevalence in the Caucasian population. [26] There is no significant difference in blood type distribution amongst mild and severe patients, or in any subgroup analysis (see Text S1) by Fisher exact test. (n = 778, p = 0.446)ABO等位基因频率与相应ABO表型与高加索人群中的已知流行率相符[26]。经费希尔精确检验（Fisher exact test）分析，轻症与重症患者的血型分布无显著差异，任意亚组分析（详见补充文本S1）亦未发现显著差异（样本量n=778，p=0.446）。