Fig. 5. Pathological features of Omicron.
Syrian hamsters were intranasally inoculated with B.1.1 (n = 3), Delta (n = 3) or Omicron (n = 3). a, b, Histopathological features of lung lesions. Lung sections from infected hamsters were stained with haematoxylin and eosin (H&E). a, Section of all four lung lobes at 5 d.p.i. In the middle panels, the inflammatory area with type II pneumocytes is indicated in red. The number in the panel indicates the percentage of the section represented by the indicated area. Right, summary of the percentage of the section represented by type II pneumocytes (3 hamsters per group). Raw data are shown in Extended Data Fig. 8. b, H&E staining of the lungs of infected hamsters. Uninfected lung alveolar space and bronchioles are shown (left). Scale bars, 250 μm (uninfected lung alveolar space and bronchioles and infected hamsters at 1 and 7 d.p.i.); 100 μm (infected hamsters at 3 and 5 d.p.i.). c, Histopathological scoring of lung lesions. Representative pathological features are shown in our previous study2. Data are mean ± s.e.m. (a, c). In a, each dot indicates the result from an individual hamster. Statistically significant differences (*P < 0.05) versus B.1.1 and Delta were determined by two-sided unpaired Student’s t-tests without adjustment for multiple comparisons. In c, statistically significant differences versus B.1.1 and Delta through time points were determined by multiple regression. FWERs calculated using the Holm method are indicated.