I always looked at the shots as a good thing.  As you say, much better than getting the full blown illness at some point.  Also, as it is a shot we know what to expect, so we have everything to hand.  Whereas with normal illness, they come out of the blue sometimes and they can be vomiting before we know they were even ill. 

My daughter is studying vaccines at school and how they work so we have been talking about this.  We think that if you gave double before the shot it would not make any difference  Sue because although you may think it would obliterate a virus normal kids who have shot would get stressed at the time of the shot anyhow and their cortisol levels would shoot up in response to that--so how do you judge what is right or what is wrong?  It cannot do any harm in my opinion, but I have always waited until we got home and monitored him for a day or so after the shot and only doubled up after the fact.  Perhaps it is best to just wait until you get home and then give a double dose of cortisol an hour or two later?