MT-ND2 and COVID-19: The mtDNA variants A4833G (Thr122Ala in NADH dehydrogenase subunit 2, ND2), A4715G (synonymous mutation in ND2), T3394C (Tyr30His in ND1) and G5417A (synonymous mutation in ND2)/C16257a (D-loop)/C16261T (D-loop) were found to increase an individual’s risk of developing severe COVID-19 in our study.