May 14, 1796. Edward Jenner puts a theory to the test: can contracting one disease save you from another? Jenner goes down in history as the man who brought us one of the greatest advances in modern medicine: the vaccine. Its discovery led to the eradication of smallpox, a virus that killed an estimated 300 million people in the 20th century alone and one of two diseases to ever be defeated. But the story of that first vaccine begins long before Jenner was even born. How did an unlikely trio in colonial America pave the way for Jenner’s life-saving innovation? And how did a strange sequence of events help us defeat one of the oldest and deadliest diseases in human history? Special thanks to our guest, Stephen Coss. You can find his book here: http://www.stephencoss.com/ Thank you also to Dr. Nathaniel Hupert for speaking with us about vaccines and epidemics.   See acast.com/privacy for privacy and opt-out information.