Edward Jenner and Cowpox
The solution to safer smallpox inoculations came from English physician Edward Jenner. And surprisingly, he got help from a cow.
Edward Jenner was born into a big family (he was one of nine children) in 1749 in Berkeley, Gloucestershire. Because his father was a clergyman, young Edward and his siblings got a good basic education. But getting variolated as a teenager had an even greater impact on his life.
Jenner was grateful that he avoided smallpox by getting variolated at a young age. But he was also aware of the risks of the procedure. As he grew older he studied both zoology and human biology. That’s how he learned of a possible link between an animal disease and the dreaded smallpox that could be the key to safer inoculations.
The disease was cowpox. And it’s no wonder it attracted attention. Cowpox was a much milder disease than smallpox, and it didn’t cause as much scarring and death in the humans who contracted it. In fact, cowpox fatalities were less than one percent.
By the time Jenner began his career in the 1770s, there was growing evidence through observations by other doctors and even farmers that getting cowpox could be a way to avoid getting smallpox.
But these observations lacked solid proof. So when Jenner noted that dairymaids who worked with infected cows rarely got smallpox, he began to study the phenomenon in a disciplined and scientific way. He hypothesized that not only did contracting cowpox result in immunity to smallpox, but also that a method could be developed to transmit this immunity.
To test his hypothesis, he found a cowpox-stricken dairymaid and used her infected blisters to vaccinate 8-year-old James Phipps. Phipps fell briefly ill but recovered. And when Jenner then exposed Phipps to smallpox and the boy didn’t contract the disease, Jenner concluded his experiment worked.
Jenner tested his vaccine on many people, including his own son, before publishing his findings. When he did self-publish his Inquiry in 1798 (its full title is An Inquiry into the Causes and Effects of the Variolae Vaccinae, a Disease Discovered in Some of the Western Counties of England, Particularly Gloucestershire, and Known by the name of the Cow Pox) it was an immediate hit and he quickly became famous. Other scientists validated his observations, and by 1799 more than a thousand people had been vaccinated.
Such was his fame that even Jane Austen knew about Jenner. In a letter to her sister Cassandra, she describes a dinner party where guests took turns reading from “Dr. Jenner’s pamphlet.”
Napoleon was another fan. Despite waging war against the British, Napoleon had Jenner vaccinate his troops and awarded him a medal, calling him one of the “greatest benefactors of mankind.”
And in 1821 Jenner was named “physician extraordinary” to the newly crowned King George IV, the monarch better known as the Prince Regent or Prinny.
Jenner’s dream, which he expressed in 1801, was that his vaccine would one day eliminate smallpox entirely. And despite problems that still had to be resolved regarding stability and distribution, the vaccine was soon on its way around the world.
In 1803, Dr. Francisco Javier de Balmis took Jenner’s vaccine on a 3-year expedition, traveling throughout the Americas and Asia, where he vaccinated thousands of people, saving countless lives.
Meanwhile, variolation fell out of favor during the early 19th century. The practice was finally banned in England in 1840 and the government instead provided free vaccinations with Jenner’s cowpox vaccine.
Just as there are anti-vaxxers today, there were those in Jenner’s time who strongly opposed vaccination. Some people thought the vaccine would make cow-like parts erupt all over their bodies. And there were religious leaders who objected to the new vaccine on the grounds that by preventing the disease the vaccine went against God’s will.
But while scientists labored and people argued the disease continued to rage. There were at least two more smallpox pandemics in Europe before 1840. And the Franco-Prussian War (1870-71) was the cause of yet another pandemic that killed half a million people.
Success at Last
Jenner’s development of a vaccine in the 1790s was only the beginning, not the end of the story of the fight against smallpox. It took the work of many other scientists to test and create a smallpox vaccine that was uncontaminated, stable and could be safely transported to countries around the world.
In 1853 Parliament made smallpox vaccinations mandatory for infants in Great Britain. By the 1860s two-thirds of all British babies had been vaccinated and there was a resulting drop in the number of infant deaths caused by the disease.
However, vaccination remained controversial and anti-vaccination leagues formed in Britain and the United States. Fortunately, vaccinations continued and the disease’s grip on mankind weakened.
Following a series of global vaccination campaigns in the 19th and 20th centuries, success came at last.
In 1979, the World Health Organization declared smallpox officially eradicated. Smallpox is still the only human disease that’s been exterminated by vaccination.
It took 180 years, but Jenner’s dream of wiping smallpox off the face of the earth finally came true.
Edward Jenner died in 1823. A humble man, he was considered a hero in his lifetime and still is today. While he may not have been the first to realize that cowpox could lead to immunity against smallpox, his work made smallpox inoculations popular and laid the groundwork for the widespread vaccinations that eventually defeated the disease.
In addition, his scientific inquiries became the basis of the modern science of immunology.
Jenner’s work put him ahead of his time – so much so that it was almost another century before French chemist Louis Pasteur developed the next vaccines, for rabies and anthrax, in the 1880s.
But why is that we call all inoculations “vaccines”? Jenner’s name for his discovery came from the Latin word for cow, “vacca.” So, technically, it should apply only to his cowpox vaccine.
But Pasteur wanted to pay homage to Jenner’s creation of the first vaccine by naming all inoculations, including the ones he developed, “vaccinations” even though cows had nothing to do with them.
Pasteur’s tribute to Jenner caught on and that’s why now we have “vaccines” for influenza, tetanus, shingles, pneumonia and many other potentially deadly diseases.
Hopefully soon there’ll be a vaccine for coronavirus, too. When that day comes, it will be yet another outcome of Jenner’s pioneering work over 200 years ago.
For more information on this topic see this article, “Edward Jenner and the history of smallpox and vaccination,” available from the National Institutes of Health.
Also, read this article on smallpox vaccines by the World Health Organization. (It’s a relief to know that despite the disappearance of smallpox there are still stockpiles of vaccine in existence.)