When the first COVID-19 vaccines were approved for emergency use last December, it felt like - at last! - our nightmare\xa0was nearly over. Then came reports of botched distribution efforts, from broken websites to factory mix-ups. Scientists created the vaccine in record time, but it was beginning to look like that might\u2019ve been the easy part.\nBut if you think vaccine distribution was a logistical nightmare in 2021, try doing it in the early 1800s. In 1796, Edward\xa0Jenner discovered that cowpox worked as a vaccine against smallpox.\xa0All you had to do\xa0was\xa0pop a cowpox sore on someone\u2019s skin and transfer the lymph fluid (a.k.a. pus) into a cut on a second person. Soon, they'd\xa0develop a few\xa0sores, but when they recovered, they'd be immune to smallpox, a\xa0far more serious disease.\nThis worked well enough for short distances, but when smallpox began to destroy Spanish colonies in the Americas, Spain had to figure out a way to move the vaccine across the ocean. Their solution was resourceful, effective, and\xa0very ethically dubious. Science writer Sam Kean\xa0brings us the story of the world's first vaccination campaign.\nGuest:\xa0\nSam Kean is a science writer, author of The Bastard Brigade, and host of the podcast Disappearing Spoon\xa0from the Science History Institute.\nFootnotes & Further Reading:\xa0\nListen to our episode on the origin of the word \u2018vaccine.\u2019\nListen to a full episode about this story on Sam Kean\u2019s podcast,\xa0Disappearing Spoon.\nCredits:\xa0\nScience Diction is produced by Johanna Mayer and Elah Feder. Elah is our Editor and Senior Producer. Daniel Peterschmidt is our composer.\xa0Nadja Oertelt is our Chief Content Officer.