TWO hundred years ago, on May 14th, 1796, Edward Jenner deliberately infected an eight year old boy with cowpox. Some weeks later the same child was exposed to the related but far more deadly disease of smallpox.
It was a dangerous experiment and anyone wanting to do the same now would probably be struck off and run out of town. Yet today, we remember Dr Jenner and the boy, James Phipps, whose collaboration helped to tame "the speckled monster".
Jenner was testing the notion that someone exposed to cowpox was less likely to succumb to smallpox. Fortunately for all concerned, the boy survived and was untouched by smallpox.
Jenner made a medical practice of what was previously a black art. Vaccination as we know it was born and the rest, as they say, is medical history.
An ancient disease
Smallpox is a highly contagious viral disease that was often fatal. The earliest incidences (from China, India and Asia) were recorded as early as 1090 BC.
Returning crusaders are thought to have brought it to Europe some 2,000 years later, from where it spread to the Americas, all with devastating consequences.
The old Chinese manuscripts also record what may well brave been the invention of vaccination according to one text an anonymous Taoist monk was using a type of vaccine in the 10th century BC. He apparently used attenuated (or weakened) germs, kept in sealed flasks, and would "vaccinate" someone by placing in their nostril a pad impregnated with some of these germs.
Certainly, by the late 10th century AD there seems no doubt that Chinese, Indian and Turkish medics had discovered the principle of using a weakened form of the disease to protect people against the real thing in a sense, using the bad to, good effect.
The practice appears to have died out in China during the 12th century, but was still widely used in Turkey, where it was seen by Lady Mary Wortley Montagu, wife of the English ambassador to Constantinople.
Writing to a friend in 1717, Lady Mary described how the engraving was done by "old women who make it their business to perform the operation", scratching a needleful of the pox into a person's arm.
Lady Mary, like many at that time, had had first hand experience of smallpox and in her own words was patriot enough to take pains to bring this useful invention into fashion in En land". Not only did she have her own children vaccinated, but during the 1721 epidemic in London, she persuaded Princess Caroline to inoculate her children as well.
Newgate guinea pigs
But Caroline was unwilling to make what at the time must have seemed a risky move. So the technique was tried first on six Newgate prisoners and poor children. Only then did the princess have her daughters, vaccinated.
Vaccination then fell out of fashion until Jenner's historic experiment in 1796. Jenner's approach was to use the related but less serious cowpox disease in cattle as the basis for his vaccine. Jenner believed that small pox originated in horses' hoove and spread from there to cattle and people.
Given that starting premise it's surprising that Jenner had any success at all, but success he had. In 1803, the Royal Jennenan Society offered free vaccination to the public, and 12,000 people were inoculated in London over the next 18 months.
That same year, one of his students, Richard Denning, coined the term vaccine, from the Latin vaccinae meaning of the cow.
Today vaccine are a common and important way of preventing many infectious diseases. But it was not until 1978 that smallpox was declared fully eradicated, following a world wide vaccination campaign by the World Health Organisation.
It was the first disease to be deliberately eradicated, although stocks of the virus are still stored in freezers at two secure locations in the US and Moscow. So successful was the vaccine campaign that the WHO is in the unusual position of having to decide later this monthly whether those last remaining stocks should also be destroyed.