I managed to miss scarlet fever, but my best friend of the time (and neighbor, which means, better part of a mile from here out in The Boonies) had it and was a little off kilter for around a month. I wasn't allowed contact with him during the interval.
Yeah, I was on limdu for a week, but was weak (physically) for about a month as well.
If it was untreated, it could have left me sterile. (I later on had 4 kids, 3 in 3 years! So, definiately NOT the case - LOL).