ACE2 and COVID-19: Lower expression of ACE2 has been observed in elderly men compared to women of the same age (64), which reinforces the observation that elderly men are more susceptible to SARS-CoV-2 infection (66) and develop more severe symptoms and complications of COVID-19 (64, 66), even more so those with associated comorbidities, although other factors such as the immune response of individuals and viral load also participate (64).