There a several possible explanations for the low rates of COVID-19 transmission and disease severity in these regions: (1) individuals living in high plateau regions are more adapted to a hypoxic environment and thus develop less serious disease (13, 35, 36); (2) reduced air pollution and increased vitamin D levels at high altitude result in milder symptoms (37, 38); (3) whether individuals in the plateau of Sichuan have ACE2 gene variants as reported (39, 40). This evidence concerns the gene ACE2 and COVID-19.