Our son had a short period of time when his blood pressure was elevated...but he was on 2 tabs of florinef at the time!!! We were able to lower it later and have had no problems since. I had been told that the first year is a bit harder to treat, but things seem to normalize after the first year. WE had no problems with immunizations. WE gave tylenol regardless of fever for the first 24hours (often sore at the sight of the shot) and would nurse immediatley after the shot.