Common Variable Immunodeficiency Support Group
Common variable immunodeficiency (CVID) is a group of 20-30 primary immunodeficiencies (PIDs) which have a common set of symptoms but with different underlying causes. CVID's underlying causes are different, but the result of these are that the body doesn't produce sufficient antibodies in response to exposure to pathogens.

as far as I understand it, no treatment can give you CVID. It is a genetic disorder. Some people think this is the case because it seems to come out of no where. The research states that the cases vary so wildly, some people do not show symptoms until their 30's, others are born with problems. the severity range is very complex.
I hope you are doing well.