If you grew up in Asia, Africa, Latin America, or parts of Eastern Europe, there’s a good chance you have a small, round scar on your upper arm. It’s about the size of a pencil eraser, slightly indented, and maybe a little lighter than the surrounding skin.
For years, you might not have thought about it. But eventually, someone asked. Or you noticed it in a photo. Or you found yourself wondering, Where did this come from?
Some people invent explanations. Others feel embarrassed, assuming it’s some childhood accident they’ve forgotten. But the truth is simpler and more universal than you might think.
That little scar has sparked decades of confusion. Let’s clear it up.
Common Misconceptions About the Round Arm Scar
Misconception #1: “It’s from a vaccine I got as a child.”
The truth: This one is actually correct—but only for certain generations and regions.
The round scar on the upper arm is indeed from a vaccine. Specifically, it’s the mark left by the BCG vaccine (Bacillus Calmette-Guérin), which protects against tuberculosis (TB).
