English country doctor who in 1796 tested the hypothesis that milkmaids who caught cowpox were immune to smallpox by inoculating 8-year-old James Phipps with cowpox material and then exposing him to smallpox — which did not develop. His 'Inquiry' (1798) introduced vaccination (from 'vacca,' Latin for cow) and sparked the eventual eradication of smallpox in 1980, the only human disease ever eradicated. Jenner refused to patent his discovery, giving it freely to the world.
- Nationality: british
- Roles: physician, scientist
