I think that sheltering does more harm than good.  You need to let your child build up an immunity to bugs and germs rather than try to hide from them.  Kids always pick stuff up, it’s just part of life.  Stop worrying so much and enjoy your little one.  My two kids have always gone to daycare and school and they have had their share of flu and tummy bugs that go around.  They have been no different to their cousins (all 25 of them) in that all kids are sick sometimes.  Some seem to get ill more than others but when compared to their non cah cousins there is no difference.  CAH is easily managed, it’s just that you need to be a bit more careful with a cah child when they are ill.  Get out and enjoy that baby of yours and please try to worry less!