Fig. 1. Disease severity following SARS-CoV-2 infection in vaccinated and non-vaccinated hamsters.
a, Experimental scheme. Syrian hamsters were vaccinated as indicated and challenged with SARS-CoV-2 (1 × 105 p.f.u. SARS-CoV-2 Delta). Prime and prime-boost experiments were performed independently. b, Body weights (in %) after virus challenge were measured until analysis timepoint and displayed according to vaccination group. Violin plot (truncated) with quartiles and median. c–l, Results of prime-vaccinated and challenged animals (c–e,i,j) and results of prime-boost-vaccinated and challenged animals (f–h,k,l): number of genomic RNA (gRNA) copies detected in oropharyngeal swabs (c,f) and homogenized lung tissue (d,g). e,h, Quantification of replication-competent virus as p.f.u. per 50 mg homogenized lung tissue. Dotted line marks the limit of detection (DL = 5 p.f.u.). Titre below the detection limits set to DL/2 = 2.5 p.f.u. i,k, Lung inflammation was scored including severity of pneumonia, alveolar epithelial necrosis and endothelialitis. j,l, Lung oedema score accounting for perivascular and alveolar oedema. m, H&E-stained left lung sections illustrate different severities of pneumonia including peribronchial cuffs and consolidated areas between different vaccine schedules and non-vaccinated animals at 5 dpc. Scale bar, 3 mm. In c–e and f–h scatter dot plots: lines indicate means, symbols represent individual hamsters. In i,j,k,l: centre lines represent medians, boxes the 25th to 75th percentiles, and whiskers the minimum to maximum values; symbols represent individual hamsters. In c–l, two-way analysis of variance (ANOVA) and Tukey’s multiple comparisons test are shown. n = 5 animals per group. *P < 0.05, **P < 0.01, ***P < 0.001 and ****P < 0.0001. Fig. 1a was created with BioRender.com.