Edward Jenner (1749–1823) was a British family doctor who practiced throughout his life in the village of Berkeley, Gloucestershire. He apprenticed for two years with John Hunter, then the preeminent medical teacher in Britain, but never took any examinations to obtain a medical degree. Instead, he purchased a medical degree from a Scottish university and later applied for and was granted an M.D. degree from Oxford University. He was keenly interested in all aspects of natural history, and he wrote a notebook describing the habits and habitats of birds in his district. A man with considerable intellectual and leadership qualities, he also founded a local medical society that survived for many generations.
At the time of Jenner's birth, smallpox was an ever present threat to life and health. When it did not kill outright, it often left a legacy of disfiguring facial pockmarks, and if it affected the eyes it caused blindness.
The practice of variolation—inoculation into the skin, or insufflation into the nose, of dried secretions from a smallpox bleb—was invented in China around 1000 C.E. and spread along the silk route, reaching Asia Minor some time in the seventeenth century. Lady Mary Wortley Montague, wife of the British ambassador to the Ottoman Empire, described the practice, also called ingrafting, in a letter to her friend Sarah Chiswell dated April 1, 1717, and imported the idea to England when she returned home. By the time Jenner was a child, ingrafting had become widespread among educated English families as a way to provide some protection against smallpox. If virulent smallpox virus had happened to survive in the batch of secretions used, however, the procedure sometimes caused severe illness and even occasional fatalities. This was generally considered to be a risk worth taking, as it was substantially less than the risk of death or disfigurement posed by epidemic smallpox itself.
Jenner knew the popular belief in Gloucester-shire that people who had been infected with cowpox, a mild disease acquired from cattle, did not get smallpox. He reasoned that since smallpox in mild form was transmitted by variolation, it might be possible to similarly transmit cowpox. He made many observations, starting in 1778, and a smallpox outbreak in 1792 provided him with the opportunity to confirm his belief that persons previously infected with cowpox did not get smallpox. In 1796 he began a courageous and unprecedented experiment—one that by modern standards would be considered unethical—that would have an incalculable benefit for humankind. He inoculated a boy, James Phipps, with secretions from a cowpox lesion. Over the following months he inoculated others, most of them children, inoculating twenty-three in all. They all survived unharmed, and none got smallpox. In 1798, Jenner published his results in An Inquiry into the Causes and Effects of the Variolae Vaccinae. His findings rank among the most important medical discoveries of all time.
The importance of Jenner's work was immediately recognized, and although there were skeptics
In due course, Jenner's discovery led to a successful campaign by the World Health Organization to eradicate smallpox. In 1980, the World Health Assembly proclaimed that smallpox, one of the most deadly scourges of mankind, had been eradicated. At the beginning of the new millennium, samples of the smallpox virus survive in secure biological laboratories in several countries, but thanks to Edward Jenner, this terrible disease need never again take a human life.
JOHN M. LAST
Jenner, E. (1798). An Inquiry into the Causes and Effects of the Variolae Vaccinae. Reprint. Birmingham, AL: Classics of Medicine Library, 1978.
LeFanu, W. R. (1951). A Bio-bibliography of Edward Jenner, 1749–1823. London: Harvey and Blythe.