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
1974 smallpox epidemic in India the last cases of smallpox, called "Target Zero", with the identification of the last smallpox patient in India occurring on May 24, 1975. By 1980, smallpox was certified as being eradicated from the world. Smallpox was eradicated due to the WHO's smallpox eradication program. This program was formally established in 1958, but because of logistics disagreements between the WHO and the Indian government, did not progress rapidly. Headway only began to take place in India after the reorganization of the WHO in the mid 1960s. Donald Henderson, who was a U.S. Public Health Services Officer stationed in New Delhi, said