Common variable immunodeficiency disease or CVID is a group of about 150 immunodeficiency disorders that are all characterized by low levels of all three types of immunoglobulin in the blood and the lack of any other underlying condition. The disease can be caused by a number of different causes, many of which are genetic in origin. A patient will not properly produce antibodies in response to infection (even dead or damaged diseases used in a vaccination). They therefore become home to many opportunistic and uncommon infections.