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How Cows and Milkmaids Gave Us Vaccines

Cornelia Poku
Cornelia Poku
June 25, 2020

Vaccines, from the Latin word vacca which means cow.

Yes, cow!

While many people know that the first-ever vaccine was for smallpox, a lot of people don’t know about the role cows had in developing that vaccine.

A recent episode of NPR’s Planet Money podcast dug a little deeper into this history.

Some experts say smallpox goes as far back as the 6th century. The devastating smallpox disease was very contagious, had a 30% death rate, and left visible scars on survivors.

The concept of immunity existed but had not been deeply explored.

At some point, in the middle ages, experimenters in China had the idea to “manufacture immunity.” They would scrape off a bit of the unfortunate scabs that smallpox left on its living victims, they would turn it into a powder and then blow it up people’s noses.

It worked—kind of. Severe infections dropped. “I mean, it doesn't work perfectly. But the death rate amongst those who have been treated is much lower,” said Josefa Steinhauer, associate professor of biology at Yeshiva University on the Planet Money episode. We don’t have exact numbers of how effective this new method was. But it was helpful enough to traverse the globe.

As this method of smallpox immunity traveled the world, it was amended and adapted, but it was still very messy and largely unsanitary.

By the late 1700’s some milkmaids in England noticed that their cows had developed something that looked similar to smallpox. But it wasn’t hurting or killing the cows. And the milkmaids themselves were getting similar bumps on their hands and were coincidentally not getting smallpox.

brown and white cattle on green grass field

Milkmaids were thought to be immune to smallpox and, before long, it became known that if you too wanted to be immune, all you had to do was get exposed to “cowpox.”

It wasn’t so simple of course. There were some negative side-effects since these humans were the first to experiment with transmitting a disease directly from its animal host to humans.

English physician Edward Jenner decided to formalize the exposure process—and he found the milkmaids to be the perfect intermediary since they worked so closely with cows anyways.

Jenner standardized the practice of spreading cowpox from human to human and the rest is history! 

We talk a lot about animals infecting humans, but this is one time in history where an animal spread a cure (technically)!

Once the concept of a vaccine was discovered, it took about 200 years to completely eradicate a devastating disease that had been around for over 1,500 years.

And today, biotech companies like SAB Biotherapeutics are using cows to develop a vaccine for COVID-19 by using the animals to produce human antibodies. This origin story about something we can no longer imagine life without speaks to the power and potential of effective One Health policies.

There is such an interconnectedness between animals and humans that we will really struggle to solve human issues without considering all the ways our relationships with animals affect us.

To learn more about One Health, read BIO’s issue brief.