Recurrent fevers in infant with no specific cause?

Has anyone experienced something like this with their littles?

Went in for my sons two month vaccine's and couldn't get them AGAIN. This is the second time we've tried, but couldn't get them because of fever.

He's had fevers on and off since he was born and we've been to the hospital twice over it but came back with normal lab values on all the routine tests! They just said he must have a virus each time, but now two months old, we're being referred to an immunologist/allergist.

If anyone's experienced something similar and would like to share, I'd appreciate it!