I can't speak from personal experience on the immunizations because I don't recall that my daughter (also salt losing CAH) ever ran into any problems when she had hers. However, if she had a fever I think I would've doubled the dose. Many pediatricians are not very knowledgeable about CAH (even though some of them think that they are!)You should really speak to your endo about this and maybe have him/her send a letter to your pediatrician that details how he feels your child should be treated in respect to fevers, minor illnesses, etc... You've found the right place to come for answers. I'm sure you'll get many responses from the people on this board. Good luck with your son. P.S. My daughter has never used the liquid form of cortef. Based upon what I've read on this board, I'm very thankful. You should insist that your endo switch you over to the pills. At our last visit to the endo (about 2 weeks ago) she told me that the problem with the liquid cortef has been getting more attention and there is serious discussion now about removing it from the market.