Edward Jenner pictured in a portrait
Esteemed scientist Edward Jenner used the eight-year-old son of his gardener for the first ever challenge trial, with just a hunch as to whether it would be successful.
Luckily, it worked. And the study led to the invention of the smallpox vaccine, which saw the debilitating disease eradicated in 1977, more than a hundred years later.
The life-threatening condition caused fever, vomiting, mouth sores and fluid-filled blisters to appear on the skin which would then develop scabs.
Victims would be left with life-long scarring on their skin, and 30 per cent of all those who suffered from the disease would eventually die.
But, after the vaccine was administered worldwide, deaths from smallpox plunged from 150million in the 1950s to zero today.
How did the first challenge trial come about?
Edward Jenner had the idea for the trial after hearing about an old country tale, which said milkmaids who caught cowpox from the animals would never catch smallpox.
Cows infected with the mild infection had a few weeping spots (pocks) on their udders, but suffered little discomfort. Milkmaids occasionally caught it from their animals and felt off-colour for a few days, but could then return to work unscathed.
Mr Jenner thought he would test the affect of cowpox as a vaccine by purposefully infecting someone with it, and then exposing them to smallpox so he could monitor their response.
What happened in the first challenge trial?
In May 1796 a milkmaid, Sarah Nelmes, came to Mr Jenner about a rash that had appeared on her hand. He diagnosed cowpox and Ms Nelmes confirmed that one of her cows, Blossom, had recently suffered from the disease.
Spotting his chance Mr Jenner asked his gardener’s eight-year-old son, James Phipps, to take part in the experiment. On May 14 he made a few scratches in the boy’s arm and inserted some skin samples from the rash on Ms Nelmes’ hand.
The boy then became mildly ill with cowpox, but recovered a few days later.
On July 1 Mr Jenner exposed his gardener’s son to smallpox, to discover whether his trial had been successful. Fortunately, the boy did not develop smallpox on that occasion, or the many times he was tested afterwards.
Source: The Jenner Institute