Could be anti-vaccine types. They don’t realize how much they are putting their children in jeopardy. I guess when they see the kid in a casket, maybe they will wake up.
There is no vaccine.[1] Prevention is by frequent handwashing, not sharing personal items, and staying away from other people when sick.
https://en.wikipedia.org/wiki/Scarlet_fever
It’s a hygiene issue. Most muslims don’t have/use TP, they use their left hand.