Thomas Geisbert, a researcher at UTMB, who helped develop several VSV Ebola vaccines, including the one made by NewLink Genetics, contends “it’s a much stronger vaccine system.” The VSV replicates, unlike the chimpanzee adenovirus vector, stimulating an immune response that Geisbert argues is as good as the one achieved by the prime-boost approach NIAID has championed. “In the context of an outbreak, where you are going to put first responders on an airplane, you don’t have time for a prime-boost,” he says. “You need a single injection.”