Ebola virus is a pretty scary disease for humans, but it’s equally scary for great apes. Since 1994, massive outbreaks in Africa have hit chimpanzees and killed an estimated third of the world’s gorillas. For the endangered chimps and critically endangered gorillas, the problem now rivals poaching and habitat loss. To inoculate a wild chimp or gorilla you’d need to deliver the vaccine via dart three times, and that’s where things get complicated. “Any vaccine that would require three immunizations — that’s going to be a logistical nightmare,” says Tom Geisbert, a vaccine expert at UTMB. Deep in the forests of central Africa darting the same animal three times seems like a long shot. It’s also unclear how long that immunity would last, too, though Geisbert suspects no more than a year. In contrast, the riskier live vaccine typically only requires one dose to protect the individual for a decade in some cases and would confer longer immunity. And if the one dose — whether of live or VLP vaccine — could be taken orally, that would be even better.