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Cytomegalovirus (CMV) infection

Medically reviewed by Last updated on Mar 13, 2024.


Cytomegalovirus (CMV) is a common virus. Once infected, your body retains the virus for life. Most people don't know they have CMV because it rarely causes problems in healthy people.

If you're pregnant or if your immune system is weakened, CMV is cause for concern. Women who develop an active CMV infection during pregnancy can pass the virus to their babies, who might then experience symptoms. For people who have weakened immune systems, especially people who have had an organ, stem cell or bone marrow transplant, CMV infection can be fatal.

CMV spreads from person to person through body fluids, such as blood, saliva, urine, semen and breast milk. There is no cure, but there are medications that can help treat the symptoms.


Most healthy people who are infected with CMV may experience no symptoms. Some experience minor symptoms. People who are more likely to experience signs and symptoms of CMV include:


Most babies who have congenital CMV appear healthy at birth.

A few babies who have congenital CMV who appear healthy at birth develop signs over time — sometimes not for months or years after birth. The most common of these late-occurring signs are hearing loss and developmental delay. A small number of babies may also develop vision problems.

The following signs and symptoms are more common in babies who have congenital CMV and who are sick at birth:

People who have weakened immunity

If your immune system is weakened, you might experience serious problems that affect your:

Healthy adults

Most people who are infected with CMV who are otherwise healthy experience few if any symptoms. When first infected, some adults may have symptoms similar to infectious mononucleosis, including:

When to see a doctor

See your doctor if:

If you have CMV but are otherwise healthy, and you're experiencing any mild, generalized illness, you could be in a reactivation period. Self-care, such as getting plenty of rest, should be enough for your body to control the infection.

When your child should see a doctor

If you know you were infected with CMV during your pregnancy, tell your baby's doctor. The doctor will likely assess your baby for hearing or vision problems.


CMV is related to the viruses that cause chickenpox, herpes simplex and mononucleosis. CMV may cycle through periods when it lies dormant and then reactivates. If you're healthy, CMV mainly stays dormant.

When the virus is active in your body, you can pass the virus to other people. The virus is spread through body fluids — including blood, urine, saliva, breast milk, tears, semen and vaginal fluids. Casual contact doesn't transmit CMV.

Ways the virus can be transmitted include:

Risk factors

CMV is a widespread and common virus that can infect almost anyone.


Complications of CMV infection vary, depending on your overall health and when you were infected.

Healthy adults

Rarely, CMV causes a healthy adult to develop mononucleosis. Other rare complications for healthy adults include problems with the digestive system, liver, brain and nervous system.

People who have weakened immunity

Complications of CMV infection can include:

Infants who have congenital CMV

An infant whose mother first became infected with CMV during pregnancy is more likely to experience complications. Complications for the baby can include:


Careful hygiene is the best prevention against CMV. You can take these precautions:

If you have weakened immunity, you may benefit from taking antiviral medication to prevent CMV disease.

Experimental vaccines are being tested for women of childbearing age. These vaccines may be useful in preventing CMV infection in mothers and infants, and reducing the chance that babies born to women who are infected while pregnant will develop disabilities.


Laboratory tests — including tests of blood and other body fluids or tests of tissue samples — can detect CMV.

During pregnancy and after delivery

If you're pregnant, testing to determine whether you've ever been infected with CMV can be important. Pregnant women who have already developed CMV antibodies have a very small chance of a reactivation infecting their unborn children.

If your doctor detects a new CMV infection while you're pregnant, a prenatal test (amniocentesis) can determine whether the fetus has been infected. In this test, your doctor takes and examines a sample of amniotic fluid. Amniocentesis is generally recommended when abnormalities that might be caused by CMV are seen on ultrasound.

If your doctor suspects your baby has congenital CMV, it's important to test the baby within the first three weeks of birth. If your baby has CMV, your doctor likely will recommend additional tests to check the health of the baby's organs, such as the liver and kidneys.

In people who have weakened immunity

Testing for CMV can also be important if you have a weakened immune system. For example, if you have HIV or AIDS, or if you've had a transplant, your doctor may want to monitor you regularly.


Treatment generally isn't necessary for healthy children and adults. Healthy adults who develop CMV mononucleosis generally recover without medication.

Newborns and people who have weakened immunity need treatment when they're experiencing symptoms of CMV infection. The type of treatment depends on the signs and symptoms and their severity.

Antiviral medications are the most common type of treatment. They can slow reproduction of the virus, but can't eliminate it. Researchers are studying new medications and vaccines to treat and prevent CMV.

Preparing for your appointment

Here's some information to help you get ready for your appointment.

What you can do

Before your appointment take these steps:

For CMV, questions to ask your doctor include:

What to expect from your doctor

Your doctor will likely ask you a number of questions, including:

In addition, if you think you have been exposed during pregnancy:

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