Fig. 6. Intranasal pretreatment with nafamostat protects mice from SARS-CoV-2 infection.

a–h Two hours before SARS-CoV-2 infection, mice were intranasally treated with 3 mg/kg nafamostat or 0.9% normal saline (vehicle). Weight loss (b), survival (c), and clinical disease symptoms (d) were monitored daily, and data were tested for significant differences using multiple t-tests. Infectious viral titers in the lungs (e) and viral loads in the lungs (f) and nasal turbinate (g) of the infected mice were detected by using a plaque assay and RT-qPCR, respectively. Symbols represent means ± SEM. h Representative images (n = 4 per group) of the hematoxylin and eosin-stained lung sections at 6 dpi. Images show low (upper; bars, 100 μm) and high magnification (lower; bars, 100 μm).