Pretreatment with the highest dose of 10 8 pfu of DEF201 resulted in 100% survival, and 10 7 and 10 6 pfu doses also significantly protected 90% and 60% of hamsters, respectively, from mortality ( Figure 1A) . Moreover, the hamster that succumbed in the 10 7 group, survived 19 days. Importantly, only one out of ten hamsters treated with 10 8 pfu of the control rAd EV virus survived the infection; however, there did appear to be a slight delay in the time to death in the hamsters that received the control virus treatment.