Mozart and smallpox the imperial family were successful, and led to greater public acceptance for the procedure. Smallpox struck the Mozart family again in the next generation: Nannerl's eldest son Leopold and two of her stepchildren caught the disease during an outbreak in the Salzburg area in 1787. All three children survived. In 1796, the discovery of vaccination—the use of the related cowpox virus to immunize against smallpox—by Edward Jenner revolutionized the ability of medicine to deal with smallpox. Vaccination reached Vienna around 1800, when yet another local epidemic created impetus for its adoption. One of the doctors trained in the Vienna campaign,
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