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.
I had bouts last winter, where I was borderline sinusitis again but I think it was my immune system struggling with flu season and the colder weather.
I also get a lot of joint pain... I think most of it is from my treatments.