FIG 7.

The rAd5-YFV vaccine in combination with rYFV provides protection to NHPs with preexisting adenovirus immunity against lethal aerosol challenge with WT CO92. To induce preexisting adenovirus immunity, four NHPs were injected in the quadriceps muscle with 5 × 10¹⁰ v.p. of Ad5-Empty (day 0). On day 30, these NHPs were immunized by the intranasal route with 1 × 10¹¹ v.p. of rAd5-YFV, followed by 50 μg of rYFV boost (emulsified 1:1 in alum adjuvant) via the i.m. route on day 42. Another four NHPs received saline only (without immunization) and served as a control. On day 85, the NHPs were challenged with WT CO92 by the aerosol route with a Dp ranging from 1.32 × 10⁷ to 8.08 × 10⁷ CFU. The animals were euthanized when a clinical score of ≥8 was reached or at the termination of the experiment, and percent survival was plotted. The P values are in comparison to the NHP control group and are based on Kaplan-Meier curve analysis.