My 14 mo. old is due for his MMR at the end of this month. We decided he should get his shot after reading about the effectiveness, risks of immunizing, and dangers if they aren't immunized. He has had 2 peds and 2 ped endos and all 4 highly recommended immunizing (including chicken pox and MMR). I think there is a risk, but the stats showed it to be so rare, and on balance the diseases themselves can be so dangerous we felt it was better to go with it.