In 1796 he scratched cowpox into a boy's arm — and invented vaccination.
Edward Jenner (1749–1823) was the English country doctor who invented vaccination: on May 14, 1796, he inoculated 8-year-old James Phipps with cowpox and proved it protected against smallpox — launching the two-century campaign that eradicated the disease worldwide in 1980.
A country doctor in Berkeley, Gloucestershire, he had heard milkmaids say they would never get smallpox because they had caught the milder cowpox. He turned folk wisdom into tested science, publishing his results in 1798.
Jenner was born in 1749 in Berkeley, Gloucestershire, and apprenticed at fourteen to a country surgeon before studying in London under the great anatomist John Hunter. He returned to Berkeley to practice — and to pursue natural history, publishing respected work on the cuckoo.
Smallpox then killed roughly one in twelve of the population and blinded or scarred countless more. The only protection was variolation — deliberately infecting patients with smallpox itself, which killed about 2 percent of those treated. Jenner sought something safer.
On May 14, 1796, Jenner took matter from a cowpox sore on the hand of the milkmaid Sarah Nelmes and scratched it into the arm of James Phipps, the gardener's 8-year-old son. The boy developed a mild fever, recovered — and on July 1 Jenner challenged him with live smallpox matter. Phipps did not fall ill. He never would.
Jenner published the 'Inquiry into the Causes and Effects of the Variolae Vaccinae' in 1798 — from 'vacca', Latin for cow, came 'vaccine' and 'vaccination'. He vaccinated his own children, gave the technique away freely, and watched it spread: Napoleon had his troops vaccinated; the practice circled the globe within years.
Opposition was fierce — cartoons showed vaccinated patients sprouting cow parts — but the evidence won. Vaccination became compulsory in Britain and across Europe through the 19th century, and the World Health Organization's global campaign drove smallpox to extinction: the last natural case was in Somalia in 1977, eradication declared in 1980.
Smallpox remains the only human disease ever eradicated — and the only one eradicated by a deliberate human campaign. The Jenner Institute at Oxford, founded in his tradition, now develops vaccines against malaria, tuberculosis and emerging threats.
