no one will suggest that you try this…but my neighbor recently had shingles and I have not given my son any imunization after much personal research on my part, i was thinking of getting him exposed i mean i had chicken pox i believe now since the vaccine the cases can be more severe than they used to be. But i am sure less severe if he were to get it as an adult. If he were to get a fever from this it would defently affect his PKU. i am not that sure about other sicknessed my son is only months old and i have not exerienced very much sickness with him. let me know whay you descided and how it does or does not go.