I was immunized as a baby (born in 1955). Everybody was immunized until sometime in the 1970’s. Son was immunized while in the navy (2005-2008) and I, too, wondered why it was necessary. I wonder if it wears off or if you are permanently immune.
I was born in 65, and every single boy in our class had a round scar on our left shoulder, most of the girls did too but some got it elsewhere so you didn’t see it.
They were as common and as overlooked as a belly button.