Expression levels were determined using the HPA (https://www.proteinatlas.org). Tissues that express ACE2 were broken down into five categories based off of the amount of ACE2 mRNA expression:

• (1, highest expression, score range: 122-10) small intestine, colon, duodenum, kidney, testis, gallbladder and heart muscle
• (2, medium high expression, score range: 5-1) adipose tissue, thyroid gland, epididymis, ductus deferens, breast, pancreas, rectum, ovary, esophagus, liver, seminal vesicle, salivary gland and placenta
• (3, medium low expression, score range: 0.9-0.5) vagina, lung, appendix, skeletal muscle, fallopian tube, lymph node, tongue, stomach and prostate
• (4, low expression, score range: 0.4-0.1) remaining tissues
• (5, no expression, score range: 0) parathyroid gland, bone marrow, monocytes, B-cells, NK-cells, dendritic cells and total peripheral blood mononuclear cell