[Elspode]

People who are pushing 50 (like me, for example) can remember when they got their polio vaccinations, I'll bet. For us, oral vaccines for polio had not yet been invented, and the process at the time involved being stuck multiple times with a needle over a dime to quarter-sized area of the upper outside bicep, just below the shoulder. It must have been semi-traumatic, because I got mine at age 4 or thereabouts, and I remember the experience pretty clearly.

Needless to say, it leaves a permanent scar, one that really doesn't look like anything else. For the younger folks, check out your parents' or older friends' arms (presuming they'll let you, and not think you're being bizarre). We've all got 'em.

As evidence of how much vaccination technology has improved over the years, I remember my mother (who would have been among the first generation of our society to have received systematic vaccination against polio) having had a scar that was the size of a silver dollar. Makes the scars we 50's babies carry around not so bad by comparison.