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,
HMS Surprise (1796) time, Le Drézénec, who had been recently promoted to "capitaine de frégate", was suffering from smallpox and was incapacitated. Consequently, her first lieutenant, Lieutenant Le Breton, commanded "Unité". Captain Thomas Fremantle in command of the frigate HMS "Inconstant" had heard there was a French frigate in Bône, and sailed to intercept her. When "Unité" arrived in the afternoon of 20 April 1796, the watch aboard "Unité" identified "Inconstant" as a neutral vessel and Le Breton did not clear the ship for action. About an hour later, "Inconstant" sailed alongside, boarded and captured "Unité" intact. About a year after capture, "Unité"