Common Variable Immunodeficiency (CVID) is an antibody deficiency that leaves the immune system unable to defend against bacteria and viruses, resulting in recurrent and often severe infections primarily affecting the ears, sinuses, and respiratory tract (sinopulmonary infections). In the majority of cases, the diagnosis is not made until the third to fourth decade of life. Permanent damage to the respiratory tract (bronchiectasis) may occur due to severe and repeated infections.

Although genetic mutations that lead to CVID have been identified, the exact cause and genetic inheritance pattern of CVID is unknown in most cases. Both males and females are affected. It is one of the most common forms of primary immunodeficiency disease (PIDD), and the severity of symptoms varies from one person with the disease to another.

CVID can be associated with autoimmune disorders that affect other blood cells causing low numbers of white cells or platelets, anemia, arthritis and other conditions such as endocrine disorders.  Gastrointestinal problems including chronic diarrhea, weight loss, nausea, vomiting and abdominal pain can also be present. In some forms of CVID, patients develop granulomas in the lungs, lymph nodes, liver, skin or other organs.

People with CVID are also at an increased risk for certain cancers (lymphoid and gastrointestinal cancers primarily).  

Treatment for CVID involves immunoglobulin replacement, preventative antibiotics, and if indicated management of autoimmune and granulomatous disease.

CVID can be diagnosed anytime from childhood through adulthood.

As with other antibody deficiencies, the most common types of recurrent infections involve the ears, sinuses, nose, bronchi and lungs. These include:

Recurrent pneumonia and chronic infections in the lungs can lead to lung damage called bronchiectasis, which can complicate treatment.

CVID may be suspected in children or adults with a history of recurrent infections involving the lungs, bronchi, ears or sinuses.

An accurate diagnosis can be made through screening tests that measure immunoglobulin levels or the number of B cells in the blood.

CVID is treated with immunoglobulin replacement therapy (IRT), which most often relieves symptoms. IRT treatments must be given regularly and are life-long.

Antibiotics are used to treat most infections that result from CVID though patients may need treatment for a longer duration than a healthy individual.