Smallpox vaccine scars! What they look like and why

For many of us, childhood memories are often anchored to small, inexplicable details—the way a certain floorboard creaked, the scent of a grandmother’s kitchen, or the sight of a mysterious mark on a parent’s skin. For decades, children across the globe observed a peculiar physical trait on the upper arms of their elders: a singular, circular scar, often characterized by a ring of small indents surrounding a larger, slightly depressed center. It was a mark so ubiquitous that it eventually faded into the background of everyday life, a commonality shared by a generation that had survived a different era.

I remember distinctly the afternoon I first truly noticed the mark on my mother’s arm. To my young eyes, it looked like a small, silver coin had been pressed into her skin and left a permanent ghost. I asked about it, but the answer I received was a fleeting bit of medical trivia that failed to stick in my pre-adolescent mind. It wasn’t until years later, while assisting an elderly woman on a train, that the curiosity returned. As I reached out to steady her, I saw the exact same ring-like indentation on her bicep. It felt like discovering a secret society’s emblem. When I later recounted the encounter to my mother, she gave me the same answer she had years prior, but this time, I was ready to understand the weight of it: it was the smallpox vaccine scar.