Health Encyclopedia

The Doctor Who Discovered Vaccines

With all the media attention on new viruses and possible flu pandemics, it's easy to forget that some of the most devastating bugs ever to plague humankind have been wiped out.

Consider smallpox. The last lab samples sit under lock and key. But two centuries ago, just before an English country doctor named Edward Jenner stepped forward to attack it, smallpox killed people by the tens of thousands.

Dr. Jenner was born in a small town in Gloucestershire in 1749. While studying medicine in London, he was offered the opportunity to be the naturalist on one of Captain Cook's expeditions to the South Seas. He declined the offer because he preferred to practice medicine in the rural district where he had been raised.

And so he did. He loved the Gloucestershire landscape, and he studied its rocks, observed the migrations of its birds, and even built the first aerial balloon seen in those parts.

One thing consistent from Gloucestershire to the South Seas in Dr. Jenner's time was smallpox. It occasionally broke out in intense and lethal epidemics.

Other times it struck people at random. It claimed lives the world over. As with chickenpox today, people who had survived one case of smallpox were immune to it. Those who survived a bout of smallpox, however, were often hideously disfigured for life by pocklike scars. A primitive form of smallpox vaccination called "variolation" had gradually become popular in England, where "matter" from a skin pox of a smallpox-infected individual was inoculated into an uninfected person's skin. Most of the time, the inoculated person got a very mild case of smallpox and seemed to be protected from getting severe smallpox. But about 2 percent of people variolated got severe smallpox as a result of the procedure and died. Variolation was also problematic because it spread other diseases. 

While Dr. Jenner treated country folk and played violin in the local music club, he thought about finding a cure for smallpox--and wondered if the answer was hidden in a bit of Gloucestershire lore.

The popular belief held that a mild disease called cowpox kept away the dangerous smallpox. Cowpox was a disease of cows, but milkmaids occasionally caught it, and those who did almost never got smallpox.

Dr. Jenner first investigated this in 1775 and within five years he had satisfied himself that cowpox was usually caused by the same (or a similar) type of virus that caused human smallpox. Human cases of cowpox were scarce in Gloucestershire at the time, however, so Dr. Jenner did not get to test his idea until more than 20 years later.

In 1796, in one of the most famous scenes in medical history, Dr. Jenner took matter from the cowpox lesions on a milkmaid's finger and injected it into the skin of 8-year-old James Phipps. James developed symptoms of cowpox: a mild fever and a small skin lesion.

Six weeks later, Dr. Jenner inoculated James with smallpox. But James did not get the disease. The process of inoculating the boy with cowpox matter--a process Jenner called "vaccination" from the Latin word for cow (vacca)--had worked.

Dr. Jenner repeated his experiment in 1798, and he published his success, announcing it to the world.

After overcoming the initial skepticism of the medical establishment, the Royal Jennerian Society was established in 1803 to give proper vaccinations.

For the first time, vaccinations were done on a sweeping scale.

The triumph paved the way for immunizations, such as the chickenpox vaccine.

Dr. Jenner died in 1823, having done more than any other person to wipe out one of history's most dreadful diseases.

The World Health Organization officially declared smallpox eradicated from the world in 1977, when the last case occurred in Africa. Its eradication was a result of mass vaccinations that began with Dr. Jenner’s cowpox vaccine. The vaccine has remained basically unchanged since then.



Medical Reviewers:

  • Foster, Sarah, RN, MPH
  • newMentor board-certified, academically affiliated clinician