For the novel coronavirus (SARS-CoV-2), however, the pattern of smell loss is different. Many people with COVID-19 reported a sudden loss of sense of smell and then a sudden and full return to a normal sense of smell in a week or two.

“Initially, we thought that the virus might be infecting and destroying the olfactory neurons. These are the cells that transmit the signal from the aroma molecule in your nose to the area in the brain where these signals get interpreted as “smell”.

However, an international collaboration showed recently that the ACE2 proteins the virus needs to invade the cells were not found on the olfactory neurons. But they were found on cells called “sustentacular cells”, which support the olfactory neurons.”

https://www.theepochtimes.com/coronavirus-scientists-uncover-why-some-people-lose-their-sense-of-smell_4196706.html?