Virological efficacy of Ronapreve in K18-hACE2 mice infected with SARS-CoV-2 Delta. Viral quantification of SARS-CoV-2 sub-genomic RNA (sgE), relative to 18S, using qRT-PCR in lung and brain samples harvested from each group 9 days post-infection. Infected mice were administered with a single IP dose of either saline (n = 4) or Ronapreve, 400 µg/mouse, in saline (n = 4). Data for individual animals are shown with the mean value represented by a black line. *, P ≤ 0.05 (unpaired, two-tailed t-test). One complete brain from the saline-administered mice was used for another in situ study. The remaining brain samples (n = 3) were available for qPCR analysis.