What should happen if a massive viral outbreak appears out of nowhere and the only possible treatment is an untested drug? And who should receive it? The two American missionaries who contracted the almost-always-fatal virus in West Africa were given access to an experimental drug cocktail called ZMapp. It consists of immune-boosting monoclonal antibodies that were extracted from mice exposed to bits of Ebola DNA. Now in isolation at an Atlanta hospital, they appear to be doing well. It's an opportunity the 900 Africans who've died so far never had. The reasons for different treatment are partly about logistics, partly about economics and, partly about a lack of any standard policy for giving out untested drugs in emergencies. Before this outbreak, ZMapp had only been tested on monkeys. But privileged humans were always going to be the first ones to try it. ZMapp requires a lot of refrigeration and careful handling, plus close monitoring by experienced doctors and scientists-better to try it at a big urban hospital than in rural West Africa, where no such infrastructure exists. And the two Americans who got it in Africa had been infected for more than a week, making its efficacy completely unknown.