WHEN THE VACCINE CAUSES THE POLIO

ONE OF THE MOST SUCCESSFUL PUBlic-health programs ever conducted, without doubt, was the U.S. campaign against polio in the 1950s and '60s. In less than a decade, the withering scourge that had at one point struck nearly 60,000 children a year was all but eradicated from American shores. Almost forgotten in the decades since, however, has been the terrible price a small number of children pay as a by-product of the protection the rest of the population enjoys. According to the Centers for Disease Control and Prevention, six babies a year, on average, contract paralytic polio from the very vaccine that...