MAINTAINING PUBLIC HEALTH in a nation of nearly 275 million people is no simple task. It takes a coordinated effort among various entities—doctors, government agencies, public health programs, schools, and individuals. These efforts have paid off in many ways.

Today, diseases that annually claim thousands of lives around the world are rarely fatal in America. Pertussis, also known as whooping cough, was once the leading cause of death in children in the United States, killing twelve thousand children each year. Today fewer than one thousand cases a year are reported in America, and most of these are in adults who survive the disease without complications. Measles, listed as one of the top six causes of death in children worldwide, is now also rare in the United States. Fewer than three hundred cases of measles were reported nationwide in 1995.

The near elimination...