Smallpox was one of history’s deadliest viral diseases, causing high fever and a distinctive rash. By the early 20th century, outbreaks killed roughly 30% of those infected, while survivors often carried permanent scars as reminders of their illness. The disease was caused by the variola virus, which spread easily and was often fatal. In response, scientists developed a vaccine using a related virus called vaccinia.

This live virus could not cause smallpox but stimulated the immune system to produce protective antibodies, marking a turning point in public health. The smallpox vaccine left a unique scar, typically a small, round or slightly oblong mark on the upper left arm, though size could vary depending on the body’s response. Unlike modern injections, the vaccine was delivered with a bifurcated needle, repeatedly jabbing the skin.

This technique caused a temporary injury, triggering scab formation and eventually leaving a lasting mark. Recipients sometimes experienced mild side effects such as fever, soreness, or swollen lymph nodes. Rare complications, including allergic reactions or infections, occurred in a small number of cases.

Routine smallpox vaccinations ended in the United States in 1972 after the disease was eradicated globally. Today, scars from the vaccine serve as historical reminders of the fight against a deadly virus. For those wishing to reduce the appearance of these scars, treatments such as sunscreen, softening ointments, or professional procedures like dermabrasion can help. The smallpox vaccine and the marks it left behind stand as a lasting symbol of scientific achievement and the power of vaccines to protect public health. Even decades later, they remind us of humanity’s triumph over one of the most lethal diseases in history.