The word 'vaccine' comes from the Latin for cow.
In 1796 Edward Jenner took material from a milkmaid's cowpox sores and put it into cuts on an eight-year-old boy's arm. Weeks later, exposure to smallpox left the boy unharmed. Jenner called cowpox Variolae vaccinae, 'pustules of the cow', and so gave us the word vaccination.
Smallpox was one of history's great killers. In Jenner's time it is estimated to have killed around one in ten people worldwide, and more in crowded towns. The main defence was variolation: deliberately infecting someone with material from a smallpox sufferer in the hope of a mild case. It often worked, but it carried real risks, including a serious infection that could spread to others. Lady Mary Wortley Montagu had brought the practice to Britain from Constantinople in 1721.
The idea that cowpox, a much milder disease caught from cattle, might protect against smallpox was already circulating. On 14 May 1796, Jenner, a country doctor in Gloucestershire, put it to the test. He took pus from the hand of Sarah Nelmes, a milkmaid who had caught cowpox from a cow called Blossom, and introduced it into two small cuts on the arm of James Phipps, his gardener's son. Phipps had a mild fever. When Jenner later exposed him to smallpox material, no disease followed.
Jenner was not the first to try cowpox. Several people had done so, including a Dorset farmer, Benjamin Jesty, who protected his wife and children during a 1774 epidemic. And the popular tale that Jenner was inspired by milkmaids' unblemished skin appears to be a myth. His real contribution, as the physician Donald Hopkins put it, was proof: he showed that people given cowpox then resisted smallpox, and that the protection could be passed from person to person rather than only from cattle. He published his cases in 1798.
The idea travelled fast. Spain's Balmis Expedition carried the vaccine to the Americas and Asia, and Napoleon, then at war with Britain, had his troops vaccinated and freed two English prisoners at Jenner's request. Britain banned variolation in 1840. In 1980 the World Health Organization declared smallpox eradicated, with vaccination central to the effort. Blossom's hide still hangs in the library of St George's medical school in London.
Source: Wikipedia — Edward Jenner · Text summarised from Wikipedia (CC BY-SA 4.0)
