History of smallpox In the late 1770s, during the American Revolutionary War, smallpox returned once more and killed thousands. Peter Kalm in his "Travels in North America", described how in that period, the dying Indian villages became overrun with wolves feasting on the corpses and weakened survivors. Smallpox was also used as a weapon by the British. In 1799, the physician Valentine Seaman administered the first smallpox vaccine in the United States. He gave his children a smallpox vaccination using a serum acquired from Edward Jenner, the British physician who invented the vaccine from fluid taken from cowpox lesions. Though vaccines were misunderstood
Vaccination policy once vaccination rates reach a certain level, even if this level is below that optimal for the community. For example, a 2003 study found that a bioterrorist attack using smallpox would result in conditions where voluntary vaccination would be unlikely to reach the optimum level for the U.S. as a whole, and a 2007 study found that severe influenza epidemics cannot be prevented by voluntary vaccination without offering certain incentives. Governments often allow exemptions to mandatory vaccinations for religious or philosophical reasons, but decreased rates of vaccination may cause loss of herd immunity, substantially increasing risks even to vaccinated individuals.