Smallpox vaccine scars: What they look like and why

As a child, I once noticed an unusual scar on my mother’s upper arm. It formed a small circle of marks around a larger indent, and although it briefly intrigued me, I eventually stopped thinking about it.

Years later, I saw the same type of scar on an elderly woman while helping her off a train. Curious, I called my mother, who reminded me that the scar was from the smallpox vaccine.

Smallpox was a deadly and highly contagious disease caused by the variola virus. It brought fever and severe skin eruptions and killed millions over centuries, with fatality rates reaching about 30 percent in the 20th century.

Because of its devastating impact, smallpox became the focus of a global vaccination effort. This campaign succeeded, and in 1980 the World Health Organization declared the disease eradicated. In the U.S., routine vaccinations ended in the early 1970s.

The vaccine left a scar because of how it was given. A two-pronged needle punctured the skin multiple times, introducing a live but weakened virus related to smallpox.

The body reacted by forming a blister that later scabbed and healed, leaving a permanent mark. This scar became a visible sign that someone had been immunized.

Today, the smallpox scar is a reminder of one of medicine’s greatest victories. Those who carry it bear a small but powerful symbol of how vaccination helped eliminate a deadly disease worldwide.