Cowpox to the mild form of smallpox and the observation that dairy farmers were immune from smallpox inspired the first smallpox vaccine, created and administered by English physician Edward Jenner. The word “vaccination,” coined by Jenner in 1796, is derived from the Latin root "vaccinus", meaning of or from the cow. Once vaccinated, a patient develops antibodies that make them immune to cowpox, but they also develop immunity to the smallpox virus, or "Variola virus". The cowpox vaccinations and later incarnations proved so successful that in 1980, the World Health Organization announced that smallpox was the first disease to be eradicated
History of smallpox a few small scratches on the arm of an eight-year-old boy who had never before contracted either smallpox or cowpox, named James Phipps. Phipps recovered as expected. Two months later, Jenner repeated the procedure using matter from smallpox, observing no effect. Phipps became the first person to become immune to smallpox without ever actually having the disease. He was variolated many more times over the course of his life to prove his immunity. When the next cowpox epidemic broke out in 1798, Jenner conducted a series of inoculations using cowpox, all of them successful except on his own son Robert.