Smallpox, a deadly virus causing severe fever and skin rashes, claimed the lives of 3 in 10 people by the early 20th century. Survivors were often left with permanent scars. The variola virus caused smallpox, but a vaccine using a related but safer virus, vaccinia, was developed. This vaccine stimulated the immune system to fight smallpox, leading to its eradication by the early 1950s. Routine vaccinations in the U.S. ended in 1972.

The smallpox vaccine left a distinctive scar, typically a small, round indentation on the arm, caused by the use of a bifurcated needle. The vaccination triggered an immune response, scabbing over and healing into a scar. Though some experienced mild symptoms, severe side effects were rare.

Today, smallpox scars are a relic of the past, with options for reducing their appearance, such as sunscreen or professional treatments. The vaccine remains a powerful symbol of humanity’s victory over smallpox.