Just as Maddisongirl said...CVID will get you IVIG on its own.

I will add that my vaccine challenge was inconclusive (likely due to autoimmune disease and how it can can effect the immune system), but I'm deficient in 3 of 4 IgG subclasses, so Medicare approved my IVIG on the labs alone and didn't require the vaccine challenge. I don't know if Medicare does this for everyone, but I have never had a problem getting IVIG with my Medicare...starting back to 1997.

I now get approved for IVIG based upon both the CVID/PID and the autoimmune based neuropathy (and receive a 3 times higher dose of IVIG for this diagnosis).