human cell atlas

The receptor protein ACE2 and the TMPRSS2 protease that can activate SARS-CoV-2 entry are expressed in cells on the inner lining of the nose. Mucus producing goblet cells and ciliated cells in the nose have the highest levels of both proteins, making them the most likely initial infection route for coronavirus. Additional key entry points were found in the cells of the eye's cornea and the intestines. This suggests other points of infection could be via the tear ducts and through fecal-oral transmission.