Common variable immunodeficiency (CVID) is the name for a group of immune system disorders characterised by recurrent infections and low antibody levels,

Patients with CVID have chronic tiredness and, due to their malfunctioning immune system, are susceptible to a very wide range of infections, which can in turn lead to more serious complications;.

It was first identified and named as a group condition in the 1950s.

Although it's known that it can be inherited, this only accounts for 10-25% of cases. And even though some gene mutations have been identified, the ways in which they manifest the disease are not understood.

In general, the causes are currently considered unknown.

Therapies for CVID are complicated by lack of treatment options, its poor definition, and the frequently-occurring long delays at arriving at a correct diagnosis.

For further details, see PMC145(6): 709–727.