Figure 5.

Prophylactic treatment with COVID‐HIG protects mice from SARS‐CoV‐2 infection. a) Experimental design. Adv5‐hACE2 was intranasally inoculated into IFNAR^−/− C57BL/6 mice (n = 8 per group). Five days after transduction, Adv5‐hACE2‐transduced mice were intraperitoneally injected with 300 mg kg⁻¹ COVID‐HIG 24 h before (prophylactic treatment) infection or with 200 µL 10% maltose 2 h after SARS‐CoV‐2 infection (control, shared with the therapeutic treatment group). b) Daily body weight changes in COVID‐HIG prophylactic‐treated or maltose‐treated mice. Data are shown as the mean ± SEM of n = 8 animals per group. Statistical significance was determined using two‐way ANOVA. **P < 0.01. c) Viral RNA levels in the lung tissues of COVID‐HIG prophylactic‐treated or maltose‐treated mice were determined using qRT‐PCR at 6 day‐ post‐infection. Data are represented as mean ± SEM of n = 8 animals per group. Statistical significance was determined using an independent t‐test. *P < 0.05. d) Histopathological analyses of COVID‐HIG‐treated or untreated mice challenged with SARS‐CoV‐2. Representative images of lung sections stained with hematoxylin and eosin at 6 day‐post‐challenge. Blue arrows indicate pathological changes in the alveolar wall and alveolar cavity. Yellow arrows indicate bronchiole lesions. Green arrows indicate pathological changes to blood vessels. The image in the lower panel is an enlarged view of the black dotted box in the image in the upper panel.