To the casual observer, the heavy snow, gale winds and high tides that struck most of the Northeast last week seemed to have turned Rhode Island into a disaster area. Like homeless refugees, long lines of crying children clinging to their parents snaked through the gloom. But it was not the storm that turned out the Sunday crowds. Rhode Island was engaged in a well-planned exercise in preventive medicine.
Health authorities had estimated that the state contained 52,000 children, aged one to twelve, who had never had measles or been vaccinated against it. Faced with mounting evidence that ordinary red or...