Fig. 1

Frequencies of mtDNA variants defining mtDNA haplogroups in controls and COVID-19 patients. Significant differences between the two groups are labelled as follows: *P < 0.05, **P < 0.01, ***P < 0.001 [adjusted P value was determined by multivariate logistic regression analysis, adjusted for age, sex, smoking and diseases (including cardiopulmonary diseases, diabetes, obesity and hypertension)]