In 1796, a country doctor in Gloucestershire named Edward Jenner noticed that milkmaids who had caught cowpox didn't get smallpox. He took fluid from a cowpox sore on a milkmaid's hand, scratched it into the arm of an eight-year-old boy named James Phipps, and waited. Six weeks later, he exposed the boy to smallpox. The boy didn't get sick. The age of vaccination had begun.
What followed over the next two centuries is arguably the single greatest reduction of human suffering in history. Vaccines eliminated smallpox entirely. They reduced polio by 99.9%. They turned measles, mumps, rubella, diphtheria, tetanus, and whooping cough from childhood killers into rare events. Before vaccines, parents buried their children with a regularity that modern families cannot fathom. Diphtheria alone killed 15,000 American children a year in the 1920s. Today it kills almost none.
The scientists who built on Jenner's insight — Pasteur, Salk, Sabin, and hundreds of others — didn't just develop medicines. They developed the principle that prevention could be more powerful than cure. Jonas Salk, when asked who owned the patent on the polio vaccine, said: "The people. Could you patent the sun?" He never made a cent from it.
Vaccines have saved more lives than any other human invention. Not buildings. Not computers. Not weapons. A scratch on a child's arm.
"Perhaps the reason the Universe gave you a broken world is so that you could have a chance to fix it."