I'm not a mother, but I know that you have to have immunization to measles to be in public school (MMR, measles, mumps, rubella shot). I don't know about someone as young as this boy, if he would have been immunized or if he could still get it. I looked up the Fifth Disease http://en.wikipedia.org/wiki/Fifth_disease and it doesn't seem like it's the same as measles, but I don't know exactly what the child's symptoms are, but if the doctor said Fifth Disease, it seems to be different.