In the 1960s, the U.S. started vaccinating kids for measles. As expected, children stopped getting measles. But something else happened. Childhood deaths from all infectious diseases plummeted. Scientists saw the same phenomenon when the vaccine was introduced elsewhere around the world. Now there's an obvious answer to the mystery: children who get the measles vaccine are probably more likely to get better healthcare in general. But Michael Mina and his colleagues have found there's more going on than that simple answer. “We found measles predisposes children to all other infectious diseases for up to a few years,” Mina says. Like many viruses, measles is known to suppress the immune system for a few weeks after an infection. But previous studies in monkeys have suggested that measles takes this suppression to a whole new level: it erases immune protection to other diseases. (National Public Radio)