Immunofluorescence data showed (29) that ACE2 is expressed at higher levels in epithelial cells of the upper respiratory tract, lung, heart, kidney, testis (30), intestine, liver, pancreas, stomach, duodenum, and rectum (31), and the higher levels of ACE2 in the cilia of the nose compared to the bronchi (32) also suggest that the nose may be the initial site of viral invasion and infection. Here, ACE2 is linked to infection.