Understanding viral tropism is an essential step towards reducing SARS-CoV-2 transmission, decreasing mortality from COVID-19, and limiting opportunities for mutant strains to arise. Currently, little is known about the extent to which distinct tissue sites in the human head & neck region and proximal respiratory tract selectively permit SARS-CoV-2 infection and replication. In this translational study, we discover key variabilities in the expression of ACE2 and TMPRSS2, essential SARS-CoV-2 entry factors, among the mucosal tissues of the human proximal airways. We show that SARS-CoV-2 infection is present in all examined head & neck tissues, with a notable tropism for the nasal cavity and tracheal mucosa. Finally, we uncover an association between smoking and higher SARS-CoV-2 viral infection in the human proximal airway, which may explain the increased susceptibility of smokers to developing severe COVID-19. This is at least partially explained by differences in IFN-beta1 levels between smokers and non-smokers.
View details for DOI 10.1016/j.xcrm.2021.100421
View details for PubMedID 34604819