Here’s The Truth Behind This Scar On People’s Upper Left Arm

Smallpox, once a deadly global threat, killed 3 in 10 infected people and left survivors with lifelong facial scars. Caused by the variola virus, it was finally defeated thanks to a groundbreaking vaccine using the live vaccinia virus — a safer relative that trained the immune system to fight off smallpox.

The vaccine, delivered using a bifurcated needle that repeatedly punctured the skin, often left a distinct scar. While side effects ranged from mild flu-like symptoms to rare complications, the vaccine’s impact was monumental.

Smallpox was declared eradicated by the early 1950s, and routine U.S. vaccinations ended in 1972. Today, only select high-risk individuals are vaccinated. The vaccine scar stands as a lasting symbol of one of medicine’s greatest victories.