As a child, I noticed a strange scar high on my mother’s arm but forgot about it over the years. That curiosity returned when I saw the exact same scar on an elderly woman’s arm. When I asked my mother, she explained it came from the smallpox vaccine.
Before the 1970s, all children were vaccinated against smallpox, and the vaccine left a distinctive scar. Smallpox was a deadly disease, killing about 3 in 10 infected people, but widespread vaccination led to its eradication in the U.S. by 1952.
The scar formed because the vaccine was given using a two-pronged needle that punctured the skin multiple times, creating blisters that healed into a permanent mark.
