Which English physician pioneered the smallpox vaccine?

English physician Edward Jenner pioneered the smallpox vaccine. In 1796, he demonstrated that infection with cowpox could protect a person from smallpox, a much deadlier disease caused by the variola virus. His work established the principle behind vaccination and produced the world’s first vaccine.

Jenner had noticed that milkmaids who contracted cowpox often appeared protected from smallpox. He tested this idea by inoculating James Phipps, an eight-year-old boy, with material from a cowpox sore and later exposing him to smallpox material. The boy did not develop smallpox, although modern ethical standards would not permit this type of experiment.

Jenner published his findings in 1798 in An Inquiry into the Causes and Effects of the Variolae Vaccinae. The words vaccine and vaccination ultimately derive from vacca, Latin for cow. Variolation, an older method that deliberately exposed people to smallpox, was different: it could provide protection but also cause severe disease and spread infection.