Vaccination disease people tried to prevent by inoculation and was the first disease for which a vaccine was produced. The smallpox vaccine was invented in 1796 by English physician Edward Jenner and although at least six people had used the same principles years earlier he was the first to publish evidence that it was effective and to provide advice on its production. Louis Pasteur furthered the concept through his work in microbiology. The immunization was called "vaccination" because it was derived from a virus affecting cows ( 'cow'). Smallpox was a contagious and deadly disease, causing the deaths of 20–60% of
1947 New York City smallpox outbreak Bar had developed a fever and pronounced rash. He was admitted to Bellevue Hospital, but because of the rash was transferred three days later to Willard Parker Hospital, a communicable disease hospital also in Manhattan. On admission to Willard Parker, the differential diagnosis was drug reaction (since Le Bar had reported taking proprietary headache powders and aspirin), erythema multiforme, Kaposi's varicelliform eruption, and smallpox. However, because Le Bar had a smallpox vaccination scar, an atypical rash, and no history of exposure, smallpox was immediately ruled out. A biopsy of the skin lesions did not reveal the Guarnieri bodies characteristic of