Lung pathology.

(A) Radar charts representing mean pathology scores, scaled 1 to 5. In all cases, scores for uninfected unvaccinated (black) and vaccinated (red) individuals are included for comparison. Mean pathology scores of challenged unvaccinated individuals are shown in blue and challenged BNT162b2 primed individuals in orange. From left to right and top to bottom: Mock vs WA1/2020. Mock vs Alpha. Mock vs Beta. Mock vs Delta. Mock vs Mu. Histological parameters: 0 = none, 1 = minimal, 2 = mild, 3 = moderate, 4 = marked, 5 = severe. Overall lesion scores are scaled to 0–5 for representation. (B) Section slides with Hematoxylin and Eosin staining of lungs from one animal in each experimental group.