As a child, I clearly remember noticing a distinct scar on my mother’s arm, positioned high up, near her shoulder. It had the appearance of a ring of small indentations surrounding a larger one.
I’m not sure why that particular scar caught my attention back then, but I do recall being intrigued by it. Over the years, though, I gradually forgot about it, as tends to happen with the small details of life.
Of course, I didn’t actually forget that the scar was there—it was always in the same spot—but I did forget the reason behind it. Maybe I asked my mother about it once, and she explained, but if so, the details didn’t stick.
That is, until a few summers ago, when I helped an elderly woman off a train and noticed the same scar in the exact same place on her arm. My curiosity was immediately rekindled, but with the train pulling away, there wasn’t much opportunity to ask her about it.
Instead, I called my mother, who reminded me that she had indeed told me about the scar before—more than once, actually. Apparently, I’d just failed to commit the information to memory. She explained that the scar was the result of the smallpox vaccine.
Smallpox, a viral infection once responsible for widespread illness, caused a severe rash and fever, with an estimated 30% fatality rate during the worst outbreaks of the 20th century. Many survivors were left disfigured. Thanks to the successful and widespread vaccination campaign, smallpox was declared eradicated in the United States by 1952. By 1972, the smallpox vaccine was no longer part of routine childhood vaccinations.
Before that time, however, all children received the vaccine, and it left a distinct mark on their arms—a visible reminder of their vaccination. This scar was like an early form of a vaccine passport, signaling that a person had been immunized against smallpox.
And yes, as you might have guessed, that’s the same scar my mother bears—just like countless others in her generation.
Why did the smallpox vaccine scar?
The smallpox vaccine left scars as a result of the body’s healing process. Unlike many vaccines given today, it was administered using a unique two-pronged needle.
The vaccine was administered through multiple punctures in the skin, unlike the single injection typically given with modern vaccines. This technique targeted the dermis, the layer beneath the outer skin (epidermis).
Once injected, the virus in the vaccine began to replicate, leading to the formation of round bumps. These bumps eventually developed into vesicles—small, fluid-filled blisters—before bursting and forming scabs.
The end result of this healing process was the characteristic scar we’ve been discussing.
Do you have a smallpox vaccine scar? Share your experience in the comments!
