When patients’ age, comorbidity (whether diagnosed or not) and ancestry (the top five principal components) were controlled, significant association (BH-corrected P < 0.01, OR = 1.56 for ACE2-hg1, OR = 0.65 for ACE2-hg2) was detected based on the ordered logistic regression between COVID-19 severities and haplogroup types (Fig. 4B). This evidence concerns the gene ACE2 and COVID-19.