Public health was and is where the largest numbers of lives are saved, usually by understanding the epidemiology of a disease—its patterns, where and how it emerges and spreads—and attacking it at its weak points. This usually means prevention. Science had first contained smallpox, then cholera, then typhoid, then plague, then yellow fever, all through large-scale public health measures, everything from filtering water to testing and killing rats to vaccination. Public health measures lack the drama of pulling someone back from the edge of death, but they save lives by the millions.
