Public health. No vaccines in the time of cholera.

With millions of people homeless, clean drinking water in short supply, and the infrastructure in tatters, water-borne diseases are one of the biggest threats in the Pakistani regions ravaged by floods. Experts are particularly worried about cholera, a disease that can cause explosive and lethal outbreaks. The International Vaccine Institute is lobbying for production of an inexpensive new oral cholera vaccine to be ramped up. But so far, the Pakistani government has no plans for a mass vaccination campaign, and the World Health Organization does not advocate one. One key problem: The vaccine requires two doses, given 2 weeks apart, which is nearly impossible to do in a massive population on the move, experts say. The debate is just the latest in an ongoing tussle about exactly how useful the new vaccine, called Shanchol—and an older, more expensive vaccine called Dukoral—is.