Extended Data Fig. 4: Immunogenicity and protective efficacy in hamsters.

a, Left, Correlation analysis of NAb titres using SARS-CoV-2 (PRNT) and rVSV-ΔG-S (SNT) for a panel of seven sera. SNT₅₀ and PRNT₅₀ values were plotted to determine the correlation between the neutralization assays with a Pearson regression coefficient of 0.77 (P = 0.04). a, Right, NAbs in sera from four convalescent patients as determined by SNT. Hamsters were vaccinated and challenged as depicted in Fig. 1b. b, Viral RNA in spleen, liver, kidney, heart and ileum of hamsters (n = 6 for each group from a single experiment) vaccinated with YF-S1/2, YF-S0 or sham, and challenged by infection with SARS-CoV-2. Viral RNA levels were determined by RT–qPCR, normalized against β-actin mRNA levels, and calculated relative to the median of sham-vaccinated hamsters. c–e, NAbs (c, d) and binding antibodies (e) in vaccinated hamsters four days after challenge with SARS-CoV-2 (n = 12 hamsters per group from 2 independent experiments; for binding antibody quantification, sera of 3 hamsters were pooled). d, Pair-wise comparison of NAbs at day 21 after immunization (circles), and 4 days after challenge (squares). f, Syrian hamsters were immunized twice intraperitoneally with 1.5 × 10³ PFU each of vaccine construct YF-S0 produced on Vero E6 cells (n = 7 hamsters), or sham (n = 3 hamsters). At day 23 after vaccination, hamsters were inoculated with 2 × 10⁵ TCID₅₀ SARS-CoV-2 and followed up for four days. g, NAbs 21 days after vaccination. h, i, Viral loads in lungs of hamsters four days after infection quantified by RT–qPCR (h) and virus titration (i). Data in g–i are from a single experiment. Data are median ± IQR. Two-tailed uncorrected Kruskal–Wallis test (b, c, e) or a two-tailed Mann–Whitney U-test was applied (g–i). ns, not significant.

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