Something as small as a circular mark on an arm can tell a surprisingly big story.
It can remind us of a time when smallpox was a serious global threat, of the enormous vaccination campaigns that helped eliminate it, and of how dramatically medicine has changed.
So the next time you notice that distinctive round scar on an older person’s arm, don’t assume it’s just an old injury.
It may be a tiny reminder of one of humanity’s greatest public-health victories.
