Figure 2. In vivo attenuation of ΔPRRA mutant.

A) Primary SARS-CoV-2 challenge schematic. Two groups of male hamsters (N=4) were challenged with 10⁵ plaque forming units of either SARS-CoV-2 WT or ΔPRRA mutant and evaluated over a 28 day time course for B) weight loss, C) disease score, D) viral titer from nasal wash, and E) viral RNA from oral swabs. F) Schematic for rechallenge of previously infected hamsters. Twenty eight DPI, hamsters from SARS-CoV-2 WT and ΔPRRA were rechallenged with 10⁵ PFU of SARS-CoV-2 WT and evaluated for G) weight loss, H) disease score, I) viral titer from nasal wash, and E) viral RNA from oral swabs. P-values based on Student T-test and are marked as indicated: *<0.05 **<0.01 ***<0.001.