If Edward Jenner were to carry out his most famous experiment today, he would be struck off the medical register. As it happened, he has emerged as the father of vaccination and a giant of immunology.
The story involves a dairymaid called Sarah Nelmes, an eight-year-old boy called James Phipps and a cow known as Blossom. Sarah came to Jenner in 1796 with a rash on her right hand and he diagnosed cowpox rather than the deadly smallpox which at that time killed as many as 10-20 per cent of the population where an outbreak occurred.
Sarah told Jenner that one of her milkers – a docile Gloucester cow called Blossom – had recently been infected with cowpox. Indeed, Sarah’s pustules were on the part of the right hand that handled the animal’s teats. Eager to test the old adage that dairymaids were protected against smallpox because of exposure to cowpox, Jenner took some pus from Sarah’s pock-mocked hand and scratched it into the arm of young Phipps, the son of his gardener.
The lad became mildly ill but recovered, confirming that cowpox can be transmitted from person to person. Jenner followed up the transmission experiment by exposing the boy directly to smallpox. He did this by variolation, a practice brought to England from Turkey by Lady Mary Wortley in 1721, when the skin is scratched with the skin scab material of someone with a mild form of smallpox. Much to Jenner’s undoubted relief, the boy survived and the first scientific validation of what became known as vaccination – a name taken from the Latin word vacca, meaning a cow.
Smallpox was declared eradicated in 1980 following a global smallpox vaccination campaign, orchestrated by the World Health Organisation. The last natural case occurred in Somalia in 1977, although a laboratory accident in 1978 in Birmingham, England, killed one person and caused a limited outbreak. Smallpox eradication is one of the greatest examples of the power of vaccination to control and even eliminate infectious diseases through adaptive immunity, and we can thank Blossom for her role in this medical achievement. Today, this carefully preserved horns can be seen on display at Dr Jenner’s House, Museum and Garden in Berkeley, Gloucestershire.