In contrast, C5178a and A249d (D-loop)/T6392C (CO1)/G10310A (ND3) variants were associated with a reduced risk of COVID-19 (OR = 0.681, 95% CI 0.504–0.919, P = 0.012; and OR = 0.639, 95% CI 0.483–0.847, P = 0.002, respectively) (Table 2 and Fig. 1). Here, MT-ND3 is linked to COVID-19.