He Accidentally Discovered the Very First Vaccine

An English physician living in a quiet village in the late 1700s made a remarkable observation. Milkmaids never seemed to catch smallpox. Somehow they appeared immune. Driven by curiosity and determination, he set out to test a theory. In the spring of 1796, he took a small sample of pus from a cowpox sore on a milkmaid's hand and introduced it into the arm of a young boy. The boy became mildly ill for a few days, but soon recovered. Weeks later, the doctor exposed him to smallox and to his astonishment, the boy stayed perfectly healthy. He named this protective method vaccination, derived from vaka, the Latin word for cow. His discovery became the world's first successful vaccine, ultimately leading to the eradication of smallox.