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
Donald Henderson United States Agency for International Development (USAID) program to eliminate smallpox and control measles during a 5-year period in 18 contiguous countries in western and central Africa. This project was funded by USAID, with field operations beginning in 1967. The USAID initiative provided an important impetus to a World Health Organization (WHO) program to eradicate smallpox throughout the world within a 10-year period. In 1966, Henderson moved to Geneva to become director of the campaign. At that time, smallpox was occurring widely throughout Brazil and in 30 countries in Africa and South Asia. More than 10 million cases and 2