Both of my kids were kind enough to bring them home from school to share with me many years ago. Well fortunately I must be immune, because I didn't get them either time, and at this late stage in life, I doubt that I ever will. As a kid I had both measles and mumps, so maybe there was some kind of connection to the immunity there?????

Here's hoping your son has a very mild case, and that Ariel manages not to catch them at all.