Fig. 1

Overview of this study. We considered four emerging zoonoses prioritized by the WHO R&D Blueprint and CEPI (Lassa fever, Middle Eastern respiratory syndrome (MERS), Nipah, and Rift Valley fever). For each, we modeled spillover, human-to-human transmission, and reactive vaccination. The left side of the figure shows the primary animal reservoirs, geography, and human-to-human transmission potential of each pathogen. The middle shows the three reactive vaccination scenarios we considered: vaccinating an entire population within the same geographic area as a detected outbreak, vaccinating healthcare workers within that geographic area, or vaccinating contacts associated with each spillover case. On the right side of the figure are the two main model outputs: an estimate of the vaccine stockpile required for reactive vaccination and the projected health impact of the reactive vaccination campaigns under each strategy