ACE2 and COVID-19: It has also been reported that ACE2 expression increases in varies types of human lung cells, including airway epithelial cells, alveolar AT2 cells, and submucosal gland secretory cells with increasing age, male gender, and smoking by a meta‐analysis of single‐cell RNA‐seq study, all of these factors are epidemiologically correlated to COVID‐19 susceptibility and lethality.36