As a child, I noticed a strange circular scar high on my mother’s arm but eventually forgot about it. Years later, I saw the same scar on an elderly woman, which reminded me to ask my mother about it.
She explained that the scar came from the smallpox vaccine, something she had told me before. Smallpox was once a deadly viral disease that killed about 3 in 10 infected people and left many others disfigured. Thanks to widespread vaccination, smallpox was eliminated in the U.S. by 1952, and routine vaccinations ended in 1972.
Before the early 1970s, nearly all children were vaccinated against smallpox, and the procedure left a distinctive scar—essentially proof of vaccination.
The scar formed because the vaccine was administered with a two-pronged needle that made multiple punctures in the skin. This caused blisters that eventually scabbed over, leaving the permanent mark many older adults still carry today.