The small, circular scar on your upper arm serves as a reminder of the smallpox vaccination you received. This vaccination was commonly administered until the 1970s to protect individuals from the Variola virus, the cause of smallpox. It achieved this by utilizing the live Vaccinia virus to induce an immune response.
After receiving the vaccination, individuals would develop blisters at the injection site. These blisters would eventually crust over and heal within a few weeks, leaving behind a distinctive circular scar. The vaccination process involved using a bifurcated needle, which was dipped into the Vaccinia solution and then repeatedly inserted into the person’s arm to administer the vaccine. With each puncture, a small amount of the vaccine was introduced, resulting in the noticeable scars.
Following the vaccination, there would be a mild swelling at the injection site, lasting for 6 to 8 hours. After this initial edema subsided, the injection site would appear normal. However, around 6 to 8 weeks later, a swelling resembling a mosquito bite would reappear. This swelling would gradually expand and develop into a nodule, eventually bursting open, secreting fluid, and forming an ulcer. The scar would then develop as the ulcer healed. This entire process typically took two to five weeks, and in some cases, the ulceration and healing process would occur two or three times.
The resulting scar from this vaccination was permanent, and it served as evidence that an individual had been immunized against smallpox. However, with the successful eradication of smallpox from most of the Western world by the early 1970s, the need for smallpox vaccination decreased significantly. In fact, by the 1980s, it was confirmed that the Variola virus had been effectively eliminated from the human population, leading to the discontinuation of smallpox vaccinations altogether.
