Smallpox vaccine scars: What they look like and why

A childhood memory of a peculiar scar on my mother’s upper arm—a ring of indents—was forgotten until years later. I noticed an identical mark on an elderly woman while assisting her, which prompted me to finally ask my mother. She revealed it was from the smallpox vaccine.

Smallpox was a deadly and highly contagious disease caused by the variola virus. It claimed an estimated 30% of those it infected in the 20th century, leaving survivors often disfigured. A global vaccination campaign led to its eradication, declared by the World Health Organization in 1980.

Routine smallpox vaccinations in the United States ended in 1972. The distinctive scar is therefore primarily seen on older adults who received the vaccine before this time.

The scar resulted from the unique administration method. A two-pronged needle was dipped into the vaccine solution and used to puncture the skin multiple times, delivering the dose into the dermis.

The vaccine contained a live virus called vaccinia. This triggered a strong immune response, causing the injection site to form a blister that would eventually scab over and heal, leaving a permanent, circular scar.

This mark served as a kind of historical “vaccine passport,” a visible sign of protection. The eradication of smallpox stands as one of public health’s greatest triumphs, achieved through worldwide vaccination efforts.

For younger generations, this scar is a relic of the past. For those who bear it, it is a personal piece of medical history and a reminder of humanity’s victory over a devastating disease.