CVID is a disorder that affects the immune system. The condition involves issues with your B cells, a type of white blood cell. Symptoms can include repeated infections and autoimmune conditions.

Though its name includes the word “common,” CVID is a rare disease. It’s known as “common” because it is the most common primary immunodeficiency. However, CVID only affects around 0.004% of people worldwide.

CVID is called “variable” because it can look very different from person to person, depending on the immunodeficiencies they have.

In 90% of cases of CVID, the exact cause is not known. However, it’s thought to involve both genetic and environmental factors. The genetic issues are believed to be due to a defect in how the body makes antibodies, key proteins that help fight infections. Antibodies and the immune system also have a key role in inflammation.

In 10% of CVID cases, the cause is known. The most common cause in these cases is changes in the TNFRSF13B gene, which is vital for proper development of B cells and antibody production.

However, in everyone with CVID, the immune system doesn’t produce enough of certain antibodies, specifically IgG, IgA, and sometimes IgM.

If you have CVID, you may notice repeated or severe infections, such as sinusitis, pneumonia, or ear infections.

Beyond infections, some people with CVID can develop other problems like autoimmune conditions, where the immune system attacks the body. Around 25% of people with CVID have an autoimmune disorder.

​Sometimes, a person will receive an autoimmune diagnosis first, without knowing the underlying cause is CVID. If immunosuppressants are then given to treat this condition, people can develop an increased risk of infections.

Symptoms of CVID can include:

  • frequent bacterial infections of the lungs, sinuses, or ears
  • diarrhea or gut inflammation caused by infections like Giardia or autoimmune enteropathy
  • skin conditions such as eczema or vasculitis (inflammation of blood vessels)
  • signs of chronic illness like weight loss, fatigue, or swollen lymph nodes
  • if repeated lung infections are left untreated, damage can occur

Due to the dysfunction of the immune system, people with CVID also have an increased risk of certain types of cancer, such as non-Hodgkin lymphoma and stomach cancer.

CVID usually appears without a clear family history and tends to be diagnosed in adulthood, although it can occur earlier. It affects both males and females.

It’s a heterogeneous condition, which means the exact immune problems vary among different people with CVID.

If you have signs of CVID, such as repeated infections, your doctor may carry out tests to check your immune function.

Diagnosing CVID involves blood tests showing low immunoglobulin levels and low antibody responses to vaccines or infections. Doctors also rule out other reasons for low antibodies before confirming CVID.

​Other important immune cells, such as T cells, may also be assessed.

A diagnosis can also come about if a person develops other conditions associated with CVID, such as autoimmune conditions or certain cancers.

An immunologist typically provides a CVID diagnosis.

The cornerstone of CVID treatment is immunoglobulin replacement therapy. This treatment provides you with purified antibodies from healthy donors to help protect against infections and restore proper function of your immune system.

Immunoglobulin therapy can be given through an intravenous infusion (IVIG) or as a subcutaneous injection (under the skin), helping to reduce infection frequency and improve your quality of life. IVIG may be given every few weeks, but subcutaneous may be given weekly.​

Alongside this, antibiotics are used to manage or prevent infections when needed. Inflammatory complications may require additional treatments, including immunosuppressive drugs, but these require careful balancing to avoid increasing infection risk.​

With proper treatment, many people with CVID can live a normal life. However, early diagnosis and treatment are crucial to avoid long-term damage, especially to the lungs.​

If you have CVID, staying vigilant about infections and reporting symptoms early is important.

Regular medical follow-ups can help monitor your lung health and immune function.

Here are some practical tips you can follow:

  • Keep up with immunoglobulin therapy schedules.
  • Take antibiotics as prescribed for bacterial infections.
  • Practice good hygiene to lower your risk of infections.
  • Avoid exposure to people with contagious illnesses when possible.
  • Maintain a healthy lifestyle with balanced nutrition and exercise.
  • Inform healthcare providers about your condition before any medical procedures.​

CVID is a common form of immunodeficiency that primarily affects your body’s ability to produce effective antibodies. This means you may have increased risk of infections and other immune problems.

Recognizing the symptoms and getting diagnosed early means you can get prompt treatment to prevent infections and other health issues. Immunoglobulin replacement therapy can prevent infections and reduce complications.

For anyone living with CVID, ongoing medical care and awareness are key to maintaining a good quality of life.