My daughter's endo never mentioned anything about the shots not working, but she did believe she should have all her immunizations just the same as any non-CAH child would. The only one she didn't approve of was the chicken pox vaccine. She felt that it would lose it's effectiveness after however many years, and with chicken pox everyone knows (and my husband is living proof) that the older you are the worse they can be when you get them. She thought it was better to just let her get it over with while she's young... it's an uncomfortable problem but not all that serious. My daughter's going to be 9 this year, and even though she's been exposed to chicken pox several times she still hasn't had them. I suppose it's bound to happen sooner or later and I don't think it's going to be a big problem.