Also the observations that elevated plasma glucose levels and diabetes are independent risk factors for mortality and morbidity in patients with SARS (18) and COVID-19 (16, 19) are beyond doubt, but consideration needs to made that these could reflect, at least in part, a state of insulin resistance and elevated insulin levels that are driving increased ACE2 expression in lung epithelial cells and aggravating disease severity. This evidence concerns the gene ACE2 and diabetes mellitus.