Fig. 3: VSV-CCHFnp1 vaccine protects mice from death against heterologous CCHFV challenge.

Six-week-old C57BL/6J mice were vaccinated intraperitoneally (IP) with 1 × 10⁴ PFU VSV-CCHFnp1 or VSV-CCHFnp2 or VSV-CCHFgpc or VSV-EBOV on day -28 relative to challenge. On day 0, mice were treated IP with MAR1-5A3 to block type I IFN receptor signaling and challenged IP with 100 TCID₅₀ CCHFV strain UG3010. Mice were weighed daily (a), and monitored for survival (b). N = 8 mice per group. c–e Viral RNA in indicated tissues at day 5 post challenge was quantified by RT-qPCR. f–h Replicating virus in indicated tissues at day 5 post challenge was quantified by a TCID₅₀ assay. N = 6 mice per group. One animal in the VSV-EBOV group succumbed during viral challenge at day 0 (cause unknown), leaving five animals in the group. The dashed line indicates the limit of detection. Statistical comparisons were calculated using log-rank test with Bonferroni’s correction for multiple comparisons test (b) one-way ANOVA with Tukey’s multiple comparisons test (c–h) and results are indicated as *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001. Comparisons with p values >0.05 were not displayed. Data shown as geometric mean plus standard deviation.