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,
Smallpox scientists performed the research to help development of new vaccines as well as trace smallpox's history, the possibility of the techniques being used for nefarious purposes was immediately recognized, leading to new regulation questions. The British used smallpox as a biological warfare agent at the Siege of Fort Pitt during the French and Indian Wars (1754–1763) against France and its Native American allies. The actual use of smallpox had official sanction. British officers, including the top British commanding generals, ordered, sanctioned, paid for and conducted the use of smallpox against the Native Americans. As described by historians, "there is no