JOHANNA MAYER: Picture a fairytale gone disastrously wrong, and there are cows everywhere. In one corner of the room, a man stares in shock at his own nose, which has sprouted a tiny cow. Meanwhile, a woman wearing a bonnet barfs out a cow. The man sitting next to her is covered in lumps that look kind of like pimples but are actually, in fact, a bunch of tiny baby cows.

A cow is crawling out of another guy's ear. A woman is sprouting a pair of cow horns. It is a cowpalooza.

And sitting at the center of this whole cow cacophony is a remarkably cow-free woman. She's white-knuckling her chair with one arm, and her other arm is in the grip of this really cold nasty-looking man. And he's plunging a big fat needle into her arm. She's getting vaccinated.

From Science Friday, this is Science Diction. I'm Johanna Mayer. Today, we're talking about the origin of the word vaccine.

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This truly wild anti-vax cartoon was published in 1802. And the message is clear. If you get vaccinated, you are turning into a cow-- stay away. Obviously, we know that's not true, but it turns out our beloved bovine friends do have a lot to do with the origins of the word vaccine and so did a person in that cartoon-- the man smack dab in the middle of those vaccinated half-cow humans sticking the needle into that scared woman's arm. His name was Edward Jenner, and he would go down in history as the inventor of the smallpox vaccine.

Smallpox-- this disease caused tiny painful pustules to pop up all over your body, and it is tough to overemphasize how devastating that disease was. Before we eradicated it, about a third of people who got it died. The British used it as biological warfare against the Native Americans. Smallpox was instrumental in the fall of both the Aztec and the Inca empires. It was bad.

And for thousands of years, it seemed like there was just no escape. From farmers in Africa to Egyptian pharaohs, everyone got it. No one was safe.

And people tried everything they could think of to protect themselves-- from herbal remedies to prescribing 12 bottles of small beer every 24 hours. That was a real recommendation from a 17th-century doctor. None of that worked. But a lot of people were doing something that did-- well, kind of.

They were deliberately exposing themselves to smallpox. And the idea was that you would get a mild smallpox infection, but it would be much less severe than a full-blown case. People in Africa and Asia and pretty much all over the world had independently figured this out.

There's even a story from the 1700s about a woman in Turkey who used to wander the marketplace with a nutshell. And inside the nutshell, she kept blisters from smallpox infections. And in exchange for a gift, she would infect you.

Obviously, giving yourself smallpox on purpose was kind of dangerous. It didn't always work. People still died. It was also sort of gross, but it was the best that people had until Edward Jenner comes along.

The story goes that one fine day, Edward overheard a milkmaid proudly declare, I shall never have smallpox, for I have had cowpox. I shall never have an ugly pockmarked face. Her words were ringing in Edward's ears years later when he decided to test this milkmaid's theory that if you had cowpox, you wouldn't get smallpox.

Now the milkmaid story, it's probably apocryphal, but it is true that Edward didn't just come up with this brilliant scheme by himself. There was also a farmer named Benjamin Jesty, who definitely tested this out before Edward. We think that Edward probably just heard about this theory from locals who'd worked with cows in their everyday lives. But in any case, there was a definite logic to this idea.

Smallpox and cowpox are part of the same viral family. The two diseases just manifest differently. Obviously, we know smallpox was serious. Cowpox, on the other hand, wasn't so bad. You usually just got kind of gross but ultimately mild sores.

So if this worked, if you actually could use cowpox to prevent smallpox, this was the answer. So for 30 years, that was the idea that was turning around and simmering in the back of Edward's brain. And in 1796, he finally decided to test it out.

The experiment was simple. Edward needed had just two things, a fresh sample of cowpox and a test subject. The cowpox sample, easy enough-- Edward knew a young woman who lived nearby.

Her name was Sarah Nelms, and she had a favorite cow. She was brown and white, and her name was Blossom. Thanks to Blossom, Sarah just so happened to have a fresh cowpox sore on her hand.

The test subject was a little more complicated. Edward chose an eight-year-old boy named James Phipps. James was the son of Edward's gardener. It's not totally clear whether he did it as a favor, or maybe the gardener just felt like he couldn't say no to his boss.

But somehow James wound up sitting in that room with Edward and Sarah. Edward scratched open James's skin, scraped some fresh material from the cowpox solution on Sarah's hand, courtesy of Blossom, and he rubbed it into James's cuts.

James got a mild fever. He was kind of uncomfortable. He lost his appetite, but then he got better, pretty much standard fare for a case of cowpox. But then came the real test.

About a month later, Edward took James aside again. And this time, he exposed him to actual fresh smallpox matter.

And James didn't get sick. It worked. Edward exposed James to smallpox more than 20 times, and he never got sick. James was immune to smallpox.

Just going to state the obvious here-- testing live viruses on an eight-year-old kid breaks about 1,000 ethical rules, but it went down in history as the first official scientifically documented vaccination. And today, we know why Edward's experiments worked. Here's a quick recap from biology class.

Since cowpox and smallpox belong to the same family, once James was infected with cowpox, his body was able to develop the defenses to kick it. And then once he was exposed to smallpox, those same defenses were able to say, oh, hey, yeah, we recognize this and nip it in the bud. So here's where we get the word vaccine.

Edward wrote up his findings in a report called "An Inquiry Into The Causes and Effects of the Variola Vaccine". In Latin, variola means pustules, and vaccine means essentially something that comes from a cow. So variola vaccine basically means cow pustules or cowpox. And for a long time, the word vaccine was used specifically to talk about using cowpox to prevent smallpox. It wasn't until almost 100 years later that it came to mean more.

And it was thanks to Louis Pasteur. He was a really big fan of Edward's, and he wanted to kind of honor him. So when Pasteur created the rabies vaccine, he suggested that we start using the word vaccination to mean anytime we inoculate against any infection, just like we use the word today.

Smallpox was eradicated in 1980-- about 200 years after Edward sat down with James Phipps. We went from this disease that killed so many people to something that's just gone kaput, and that's not all thanks to Edward Jenner. All those people across Africa and Asia, that woman with the blisters and the nutshell in Turkey, the farmer who first guessed at the cowpox solution, they laid the foundation.

But Edward rigorously tested it, and he wrote it down. And he really dedicated himself to the cause. He didn't just run tests and publish papers. Decades after his famous experiment, Edward kept doing the hard work himself, giving out vaccinations to local poor kids for free. I can't get this image from Edward's later years out of my head.

In the garden of his country house, in the shadow of some yew trees sits this little stone hut, and that's where he would give these vaccinations. It's got a thatched roof. It's decorated with these big chunks of bark from forest trees. Honestly, it looks kind of like a toadstool or like a Smurf hut.

But there are stories of kids lining up all the way through Edward's garden, down the block, and into the nearby town, all waiting for Edward to inoculate them. The man who helped end this truly horrific disease would sit in that backyard hut devoting himself to this cause that he believed in above all else. He called the hut the temple of vaccinia.

Science Diction is written and produced by me, Johanna Mayer, with production and editing help from Elah Feder. Our senior editor is Christopher Intagliada, and we had additional story editing from Nathan Tobey. Our theme song and music by Daniel Peterschmidt, fact-checking help from Michelle Harris. We had mixing help from Kaitlyn Schwalje.

For more stories like these subscribe to Science Diction wherever you get your podcasts. And if you want to see a picture of Edward Jenner's temple of Vaccinia, head on over to sciencefriday.com/vaccine. You can also find an article there by Howard Markel on the same topic.

Special thanks this week to Dr. Elena Conis, Dr. Gareth Williams, and the Edward Jenner Museum. And as always, huge thank you to the entire Science Friday staff. We'll see you next time with a new word.

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