Edward Jenner: The Father of Modern Vaccination

Edward Jenner pioneered the creation of the smallpox vaccine and his work is reflected in modern vaccines.

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By Emily Young-Squire

Pharmaceutical companies like Pfizer and Moderna are working to distribute their COVID-19 vaccines as the pandemic plagues hundreds of thousands of people globally. Their vaccines work by introducing weakened or inactive parts of a particular infectious organism to a human body. In more recent vaccines, it is the antigen, a substance that can induce an immune response, that is introduced, rather than the organism. The immune system will react and produce the antibodies necessary to fight off the real pathogen when it infects the body. As millions are already vaccinated against COVID-19 and many more will be in the coming months, it is important to recognize the scientist who made vaccinations so widespread: Edward Jenner.

It all started with smallpox, a lethal illness that affected humans since the first agricultural settlements 12,000 years ago. There is even evidence of scarring caused by the disease on mummified remains of ancient Egyptians. Those who contracted smallpox were very likely to die from it, and those who survived were likely left disfigured due to extreme scarring and blindness. During the 18th century, many practiced crude treatments in a desperate attempt to find a cure: sleeping with the windows open, keeping bed sheets at half-mast, and drinking 12 small beers a day. No one had an answer to the mysterious plague because the germ theory had not yet been proposed.

Edward Jenner, the father of vaccination, could have been one of the many who perished after encountering smallpox as a child. When Jenner was eight years old, he was treated for smallpox through inoculation, a first-rate medical treatment at the time. It involved fasting, purging, and bleeding to prepare the patient before introducing dried pustules, pimple-like overgrowths of bacteria from a recent smallpox victim, into a wound on the patient's hand. If the young patient then developed smallpox and survived, they would be immune to the disease. Unfortunately, not many people survived the variolation process, but fortunately, Jenner did. When he grew up, he trained in London to become a surgeon but later returned home to Berkeley to open a private practice.

During this transition, Jenner came into close contact with cows and milkmaids from the surrounding farms. There, he noticed that milkmaids enjoyed immunity from smallpox despite never going through the difficult variolation process that he had endured. Jenner suspected that there was a correlation between cowpox immunity and smallpox immunity. On a superficial level, cowpox was a disease that looked a lot like smallpox, with patients having crusty overgrowths on their skin. However, cowpox was a relatively harmless disease compared to smallpox. To test his hypothesis, Jenner decided to purposefully introduce cowpox to a young patient to determine whether they would also gain immunity to smallpox.

On May 14, 1796, Jenner carried out his risky plan on his gardener’s eight-year-old son, James Phipps. He took a sample of pus from a local milkmaid and introduced it to scratches he made on Phipps’s arm. Phipps contracted cowpox but recovered quickly in a week. Jenner then introduced variola smallpox material into Phipps. Astonishingly, Phipps did not develop any signs of smallpox and was consequently considered immune. Jenner wrote of his findings, but the Royal Society of Medicine shut him down when they realized that his discovery was a threat to their established practices. When he attempted to self-publish, he was met with extreme opposition. Cartoons at the time suggested that patients were afraid to be treated with material from a cow because they too would begin to show bovine characteristics. Jenner even coined the word “vaccination” through the Latin word for cow, vacca. Through Jenner’s influential friends such as Frederik Augustus, Napoleon Bonaparte, and Thomas Jefferson, the practice gradually became well respected by established doctors and the general public.

But how did making two scratches on an arm turn into the vaccination method we know today? Fifty years after Jenner’s discovery, the hypodermic syringe was invented. This syringe had the sanitation advantage of using a sealed glass tube that contained the medication or fluids, lowering the risk of spreading the infection. In 1885, Louis Pasteur used one to vaccinate a rabies-infected individual who then survived, representing great progress for immunization. However, hypodermic syringes were also limited because their large needles could easily rust or break, their glass barrels often broke, and their tips leaked. The needles also needed to be sterilized and sharpened.

Luckily, disposable needles were invented in the 1960s, providing a safer and cleaner way to inject vaccines. Through technological improvements, sharper and thinner needles were created. Scientists and engineers are still trying to find other methods of injection, such as through the mouth or nose, that would get the vaccine into the body with minimal side effects and a cost-effective method. As of right now, hypodermic injection, which the COVID-19 vaccine is administered as, is still the most common method.

Nearly two centuries after Jenner’s time, the World Health Organization declared that smallpox was “dead” in 1980, concluding their campaign to eradicate the deadly disease. It became the first major infectious disease to be eliminated completely. Thanks to significant progress in vaccinations, once fatal diseases like polio, measles, and mumps are nearly eliminated from most countries. Today, the COVID-19 vaccines are using a new technique where mRNA from the SARS CoV-2 virus is introduced to the body. However, the vaccine still maintains some of Jenner’s ideas of producing an immune response against the disease. There is no doubt that the work Jenner started saved and will continue to save millions of lives.