The 1947 New York City smallpox outbreak occurred in March, 1947 and was declared ended on April 24, 1947. The outbreak marked two milestones for America. First, it was the largest mass vaccination effort ever conducted for smallpox in America, and second, it marked the last outbreak of smallpox in America. Within three weeks of the discovery of the outbreak, the U.S. Public Health Service, in conjunction with New York City health officials, had procured vaccine and inoculated over 6,350,000 adults and children. Of that number, 5,000,000 had been vaccinated within the first two weeks. The rapid response was credited with limiting the outbreak to 12 people, 10 of whom recovered, while 2 died.