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,
Vaccination policy However, mandatory vaccination policies raise ethical issues regarding parental rights and informed consent. To eliminate the risk of disease outbreaks, at various times governments and other institutions established policies requiring vaccination. For example, an 1853 law required universal vaccination against smallpox in England and Wales, with fines levied on people who did not comply. In the United States, the Supreme Court ruled in "Jacobson v. Massachusetts" (1905) that states have the authority to require vaccination against smallpox during a smallpox epidemic. All U.S states require that children be vaccinated in order to attend school; only three states (Mississippi, West Virginia,