In 1798, Edward Jenner published his work on the development of a vaccination that would protect against smallpox.

Two years earlier, in 1796, he had first speculated that protection from smallpox disease could be obtained through inoculation with a related virus, vaccinia or cowpox. He tested his theory by inoculating eight-year-old James Phipps with cowpox pustule liquid recovered from the hand of a milkmaid, Sarah Nelmes.