A new, inexpensive, easy-to-use cholera vaccine that is stockpiled for emergencies worked very well during a cholera outbreak in Africa, Doctors Without Borders reported recently.

Two doses of the oral vaccine called Shanchol, invented in Vietnam and produced in India, provided 86 percent protection against cholera, which causes diarrhea and dehydration so severe that it can kill, a study published in The New England Journal of Medicine last month found.

The study was done by Epicentre, the research arm of Doctors Without Borders, and the Health Ministry of Guinea, during a large 2012 outbreak there. More than 316,000 doses were given out, and about 75 percent of the residents of cholera-affected areas got two doses, which is good coverage for an outbreak already underway.

Two vaccines have been stockpiled by the World Health Organization since 2013. But the older vaccine, Dukoral, made by a subsidiary of Johnson & Johnson, was invented mostly for the wealthy travel market.