it had a long been known among farmers that people who work with cows rarely caught smallpox, instead, they often cough a similar but much milder disease called cowpox. A British doctor named Edward Jenner was fascinated by this. And so he studied cowpox. He became convinced that, by injecting people with cowpox, he could protect them against the much worse Disease smallpox. In 1796,he vaccinated a boy with cowpox and, two months later, with smallpox. The boy did nit get smallpox. In the next two years, Jenner vaccinated several children in the same way, and none of them go the disease.