Edward Jenner
Invention of the vaccine

Inoculation was already a standard practice in Asian and African medicine but involved serious risks, including the possibility that those inoculated would become contagious and spread the disease to others. In 1721, Lady Mary Wortley Montagu had imported variolation to Britain after having observed it in Istanbul. While Johnnie Notions had great success with his self-devised inoculation (and was reputed not to have lost a single patient), his method's practice was limited to the Shetland Isles. Voltaire wrote that at this time 60% of the population caught smallpox and 20% of the population died from it. Voltaire also states that the Circassians used the inoculation from times immemorial, and the custom may have been borrowed by the Turks from the Circassians. In 1766, Daniel Bernoulli analysed smallpox morbidity and mortality data to demonstrate the efficacy of inoculation.

By 1768, English physician John Fewster had realised that prior infection with cowpox rendered a person immune to smallpox. In the years following 1770, at least five investigators in England and Germany (Sevel, Jensen, Jesty 1774, Rendell, Plett 1791) successfully tested in humans a cowpox vaccine against smallpox. For example, Dorset farmer Benjamin Jesty successfully vaccinated and presumably induced immunity with cowpox in his wife and two children during a smallpox epidemic in 1774, but it was not until Jenner's work that the procedure became widely understood. Jenner may have been aware of Jesty's procedures and success. A similar observation was later made in France by Jacques Antoine Rabaut-Pommier in 1780.

Jenner postulated that the pus in the blisters that affected individuals affected by cowpox (a disease similar to smallpox, but much less virulent) protected them from smallpox. On 14 May 1796, Jenner tested his hypothesis by inoculating James Phipps, an eight-year-old boy who was the son of Jenner's gardener. He scraped pus from cowpox blisters on the hands of Sarah Nelmes, a milkmaid who had caught cowpox from a cow called Blossom, whose hide now hangs on the wall of the St. George's Medical School library (now in Tooting). Phipps was the 17th case described in Jenner's first paper on vaccination.

Jenner inoculated Phipps in both arms that day, subsequently producing in Phipps a fever and some uneasiness, but no full-blown infection. Later, he injected Phipps with variolous material, the routine method of immunization at that time. No disease followed. The boy was later challenged with variolous material and again showed no sign of infection. No unexpected side effects occurred, and neither Phipps nor any other recipients underwent any future 'breakthrough' cases.

Jenner's biographer John Baron would later speculate that Jenner understood one could be inoculated against smallpox by being exposed to cowpox by observing the unblemished complexion of milkmaids, rather than building on the work of his predecessors. The milkmaids story is still widely repeated even though it appears to be a myth.

Donald Hopkins has written, "Jenner's unique contribution was not that he inoculated a few persons with cowpox, but that he then proved that they were immune to smallpox. Moreover, he demonstrated that the protective cowpox pus could be effectively inoculated from person to person, not just directly from cattle." Jenner successfully tested his hypothesis on 23 additional subjects.

Jenner continued his research and reported it to the Royal Society, which did not publish the initial paper. After revisions and further investigations, he published his findings on the 23 cases, including his 11-month-old son Robert. Some of his conclusions were correct, some erroneous; modern microbiological and microscopic methods would make his studies easier to reproduce. The medical establishment deliberated at length over his findings before accepting them. Eventually, vaccination was accepted, and in 1840, the British government banned variolation – the use of smallpox to induce immunity – and provided vaccination using cowpox free of charge (see Vaccination Act).

The success of his discovery soon spread around Europe and was used en masse in the Spanish Balmis Expedition (1803–1806), a three-year-long mission to the Americas, the Philippines, Macao, China, led by Francisco Javier de Balmis with the aim of giving thousands the smallpox vaccine. The expedition was successful, and Jenner wrote: "I don't imagine the annals of history furnish an example of philanthropy so noble, so extensive as this". Napoleon, who at the time was at war with Britain, had all his French troops vaccinated, awarded Jenner a medal, and at the request of Jenner, he released two English prisoners of war and permitted their return home. Napoleon remarked he could not "refuse anything to one of the greatest benefactors of mankind".

Jenner's continuing work on vaccination prevented him from continuing his ordinary medical practice. He was supported by his colleagues and the King in petitioning Parliament, and was granted £10,000 in 1802 for his work on vaccination. In 1807, he was granted another £20,000 after the Royal College of Physicians confirmed the widespread efficacy of vaccination.
keywords:forbidden_words