An experimental vaccine for hepatitis E has proved nearly 96 percent protective in a test among soldiers in Nepal. . . . Other hepatitis vaccines don't work against hepatitis E, and there's no effective treatment for the disease that it causes. By some estimates, one-third of the world's population, mainly in Africa and Asia, has been infected at some time. A hepatitis E infection causes fatal liver failure in 1 to 3 percent of patients showing symptoms.
From Science News (subscription only) (with their source).