ACE2 and COVID-19: In the hematogenous route, the virus may infect endothelial cells of the blood–brain barrier or leukocytes to disseminate into the CNS.46 ACE2 is widely expressed on the epithelial cells of the oral mucosa.47 Moreover, the olfactory route is a shortcut for many viruses to enter the CNS.48 Olfactory receptor neurons project dendrites into the nasal cavity and extend axons through the cribriform plate into the olfactory bulb.48 Meanwhile, hyposmia and hypogeusia are reported in some COVID-19 patients.49 These evidences could partly support our conclusion.