Many people bear a small, round scar on their upper arm, a lasting trace from the smallpox vaccine, which was widely administered before the 1970s. This vaccine used the live Vaccinia virus to build immunity against the Variola virus, which causes smallpox.
Following the vaccination, “blisters formed at the injection site, eventually healing into a circular scar,” as described in the original article. The process involved multiple needle pricks that caused blisters, which led to temporary swelling and a lump similar to a mosquito bite. This lump grew, oozed fluid, and eventually healed into the scar that remains today.
By the early 1970s, smallpox had been eradicated in the Western world, and vaccination ceased in the 1980s due to the lack of further risk. The scar now stands as a historical reminder of a once-lethal disease.