Just randomly occurred to me earlier when talking to another of the parents.
I have a vague memory of someone saying that their school let them know when there were parents with immune issues, but then i was thinking, its hardly rare, is it?
But then, we were talking about kids being sent to school ill, and i'm sure the school would like an excuse to remind people not to send in their children when they are going to make everyone else ill 
What do you think?