The Mysterious Arm Scar That Quietly Tells the Story of Humanity’s Greatest Medical Victory
For many people born before the early 1970s, a small circular scar on the upper arm is more than just a childhood mark—it’s a lasting reminder of one of medicine’s greatest achievements. The distinctive scar, often featuring a ring of tiny impressions surrounding a central indentation, was left behind by the smallpox vaccine.
Unlike modern vaccines administered with a single injection, the smallpox vaccine used a special two-pronged needle that made several quick punctures in the skin. A blister formed, followed by a scab that eventually healed, leaving the familiar circular scar many older adults still carry today.
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