Abstract
Interferons establish innate antiviral immunity. Two recent papers in JEM by Lopez et al. (2021. J. Exp. Med.https://doi.org/10.1084/jem.20211211) and Cheemarla et al. (2021. J. Exp. Med.https://doi.org/10.1084/jem.20210583) show that an appropriate supply of antiviral interferon enables epithelial cells of the nasopharyngeal mucosa to inhibit SARS-CoV-2 growth and that interferon-induced mucosal genes serve as biomarkers of infection.