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 in Mexico caused Viceroy Félix Calleja to take preventive measures like fumigations and vaccination, which were successful. There were sporadic outbreaks until 1826 when smallpox appeared in Yucatán, Tabasco and Veracruz brought by North American ships. In 1828, there were reported cases in Hidalgo, Oaxaca, State of Mexico, Guerrero, Chiapas, Chihuahua and Mexico City. Efforts to eradicate smallpox in Mexico started with Dr José Ignacio Bartolache who wrote a book in 1779 about smallpox called “Instrucción que puede servir para que se cure a los enfermos de las viruelas epidemicas que ahora se padecen en México”(Instructions that may help to cure smallpox