Once inside the body, the virus moves around by attaching to the same ACE2 protein on other tissues deep in the lungs, the heart, and the kidneys. The receptor can also be found in the lining of blood vessels, and possibly even the taste buds on our tongues. This is one reason why Covid-19 patients may present such a diverse set of symptoms.
A paper recently published in JAMA examines one measure of the amount of receptors in the noses of children and adults. I say one measure because what is measured is not the protein responsible for attachment, but rather the RNA which directs its production. Usually but not always, the amount of RNA in cells determines the amount of the corresponding protein. The authors assume that is the case, and their conclusion depends on that assumption.
Originally published on Forbes (May 27, 2020)