The Mark of a Smallpox Vaccine

Many of us have a small, round scar on our upper arm—a lasting reminder of the smallpox vaccine. Before the 1970s, this vaccine was a common experience for many people. It used the live Vaccinia virus to trigger an immune response against the deadly Variola virus, which caused smallpox.

The Vaccination Process

After receiving the shot, people often saw blisters appear at the injection site. These blisters eventually healed and left behind a circular scar. Each needle prick delivered a small amount of the vaccine, which caused the blisters.

The Formation of the Scar

Initially, the injection site swelled after the shot, but it quickly returned to normal. However, 6 to 8 weeks later, a lump resembling a mosquito bite would form. This lump grew into a tumor that eventually opened, oozed fluid, and turned into an ulcer. Finally, it healed into a scar that lasted forever.

The End of Smallpox

Smallpox was eradicated in most of the Western world by the early 1970s. Consequently, vaccinations ceased in the 1980s due to a lack of exposure to the Variola virus. Today, the scar serves as a historical reminder of a once-dangerous disease.