This hypothesis proposes that infection of olfactory epithelium (OE)-related cells, such as sustentacular and basal cells, is the basis of anosmia-related symptoms in COVID-19 patients (Ref #1)

1. Gene expression profiles of human nasal biopsy samples revealed that neither ACE2 nor TMPRSS2 were detected in OSNs, which would be necessary for SARS-CoV-2 infection. This was confirmed by immunostaining of human biopsy tissue.

2. Immunostaining revealed, however, that OE cells such as sustentacular and basal cells express ACE2. This suggests that the MOA for COVID-19-mediated anosmia may be from damage of these OE cells.

3. These findings are confirmed by experiments performed in Syrian hamster models of SARS-CoV-2 infection (Ref #2)