Edward Jenner Biography

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World of Microbiology and Immunology on Edward Jenner

Edward Jenner discovered the process of vaccination, when he found that injection with cowpox protected against smallpox. His method of immunization via vaccination ushered in the new science of immunology.

Jenner was born in Berkeley, England, the third son and youngest of six children of Stephen Jenner, a clergyman of the Church of England. He was orphaned at age five and was raised by his older sister, who was married to a clergyman. When Jenner was thirteen years old, he was apprenticed to a surgeon. Then in 1770, he moved to London, England, to work with John Hunter (1728 - 1798), an eminent Scottish anatomist and surgeon who encouraged Jenner to be inquisitive and experimental in his approach to medicine. Jenner returned to Berkeley in 1773, and set up practice as a country doctor.

During and prior to Jenner's lifetime, smallpox was a common and often fatal disease worldwide. Many centuries before Jenner's time, the Chinese had begun the practice of blowing flakes from smallpox scabs up the nostrils of healthy persons to confer immunity to the disease. By the seventeenth century, the Turks and Greeks had discovered that, when injected into the skin of healthy individuals, the serum from the smallpox pustule induced a mild case of the disease and subsequent immunity. This practice of inoculation, termed variolation, reached England by the eighteenth century. However, it was quite risky as those who were inoculated frequently suffered a severe or fatal case of smallpox. Despite the risk, people willingly agreed to inoculation because of the widespread incidence of smallpox and the fear of suffering from terribly disfiguring pockmarks that resulted from the disease.

As a young physician, Jenner noted that dairy workers who had been exposed to cowpox, a disease like smallpox only milder, seemed immune to the more severe infection. He continually put forth his theory that cowpox could be used to prevent smallpox, but his contemporaries shunned his ideas. They maintained that they had seen smallpox victims who claimed to have had earlier cases of cowpox.

It became Jenner's task to transform a country superstition into an accepted medical practice. For up until the mid - 1770s, the only documented cases of vaccinations using cowpox came from farmers such as Benjamin Jesty of Dorsetshire who vaccinated his family with cowpox using a darning needle.

After observing cases of cowpox and smallpox for a quarter century, Jenner took a step that could have branded him a criminal as easily as a hero. On May 14, 1796, he removed the fluid from a cowpox lesion from dairymaid Sarah Nelmes, and inoculated James Phipps, an eight-year-old boy, who soon came down with cowpox. Six weeks later, he inoculated the boy with smallpox. The boy remained healthy. Jenner had proved his theory. He called his method vaccination, using the Latin word vacca, meaning cow, and vaccinia, meaning cowpox. He also introduced the word virus.

The publication of Jenner's An Inquiry into the Causes and Effects of the Variolae Vaccinae set off an enthusiastic demand for vaccination throughout Europe. Within 18 months, the number of deaths from smallpox had dropped by two-thirds in England after 12,000 people were vaccinated. By 1800, over 100,000 people had been vaccinated worldwide. As the demand for the vaccine rapidly increased, Jenner discovered that he could take lymph from a smallpox pustule and dry it in a glass tube for use up to three months later. The vaccine could then be transported.

Jenner was honored and respected throughout Europe and the United States. At his request, Napoleon released several Englishmen who had been jailed in France in 1804, while France and Great Britain were at war. Across the Atlantic Ocean, Thomas Jefferson received the vaccine from Jenner and proceeded to vaccinate his family and neighbors at Monticello. However, in his native England, Jenner's medical colleagues refused to allow him entry into the College of Physicians in London, insisting that he first pass a test on the theories of Hippocrates and Galen. Jenner refused to bow to their demands, saying his accomplishments in conquering smallpox should have qualified him for election. He was never elected to the college. Jenner continued his medical practice, as well as collecting fossils and propagating hybrid plants in his garden, until his death from a stroke at the age of 73.

Nearly two centuries after Jenner's experimental vaccination of young James, the World Health Organization declared endemic smallpox to be eradicated.