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Cytomegalovirus (CMV)

About CMV

Cytomegalovirus (CMV) is a common infection that can affect anyone. Many adults will have had a CMV infection by the time they're 40 years old, but most won't know it because it usually doesn't cause symptoms.

In healthy kids, a CMV infection is rarely serious and any symptoms it does cause tend to be mild. But CMV infection can be serious for babies and people with weakened immune systems due to illness or medicines, or for an unborn child if the mother has the virus.

Once a person has the infection, the virus (a member of the herpesvirus family) stays in the body but usually lies dormant (or inactive). It can come back weeks or years later and cause more serious illness, but this is more common in kids with immune system problems.


The symptoms of a CMV infection vary depending on the age and health of a child, and the number of times a child has had it.

Babies who are infected in the womb usually show no symptoms of a CMV infection after they're born. In a few cases, there are symptoms at birth, which can include premature delivery, being small for gestational age, jaundice, enlarged liver and spleen, microcephaly (small head), and feeding difficulties. These babies are also at high risk for developing hearing, vision, neurological, and developmental problems.

Premature and ill full-term infants who are infected soon after birth are at risk for neurological and developmental problems over time.

Although CMV infections that happen in kids after the newborn period usually don't cause significant illness, some kids may develop pneumonia, hepatitis (inflammation of the liver), or a rash.

Older kids and teens who become infected may have mono-like symptoms, including fatigue, muscle aches, headache, fever, and enlarged liver and spleen. These symptoms tend to be mild and usually last only 2 to 3 weeks.

CMV can cause serious infections in people who have received organ transplants or those whose immune systems are weakened. In someone with AIDS or HIV, CMV infection may involve the lungs, nervous system, gastrointestinal tract, and the eyes, sometimes causing blindness.


If symptoms of CMV do appear, how long they last depends on how the infection happens and the age and general health of the person who has it. For example, serious CMV infections before birth may cause developmental problems that affect a child for a lifetime. On the other hand, infection in teens may last only 2 to 3 weeks and cause no lasting problems.

How it Spreads

Among kids, the virus is commonly spread in childcare centers or preschool settings, where it passes easily through indirect contact, especially though contaminated toys.

In the United States, about 1% of infants are infected with CMV before birth — usually only if the mother has developed a first-time CMV infection during pregnancy. An infected mother can pass the virus to her child before, during, or after birth.

Anyone with a new or past CMV infection can transmit the virus to others, even if he or she isn't showing any symptoms. But transmission usually requires fairly close contact; the virus can be spread through saliva, breast milk, vaginal fluids, semen, urine (pee), and stool (poop). It also can be present in blood products and donated organs, causing infection after a blood transfusion or organ transplantation.

Diagnosis & Treatment

Doctors can diagnose the infection by taking a culture from a person's throat, urine, blood, or other body tissues or fluid. Blood tests also can look for certain antibodies that are part of the immune system's response to a CMV infection. Sometimes other tests are used.

No specific treatment is recommended for otherwise healthy kids with CMV infection.

In newborns, organ-transplant patients, those being treated for cancer, and kids who have immune disorders such as AIDS, CMV infection can be life-threatening. These people may be treated with intravenous (IV) antiviral medication, usually in a hospital. Oral antiviral medicine also might be used at home once the infection is under control and no longer poses a serious risk. Because these antiviral medicines can have serious side effects, doctors use them with caution, especially in children.

In bone-marrow transplant patients, additional CMV-immune globulin (CMV-IVIG) and the antiviral drug ganciclovir given intravenously can be helpful in fighting CMV infections.


Currently, there is no vaccine to prevent CMV infection. For pregnant women, women who might become pregnant, childcare personnel, and anyone who has close contact with children, hand washing can help reduce the risk of infection. It's also a good idea to not share eating utensils with young kids and to avoid close contact with anyone who has the infection.

A mother who has a CMV infection shouldn't stop breastfeeding her baby — the benefits of breastfeeding are believed to outweigh the risks of passing CMV to the baby, who is unlikely to develop any symptoms if infected.

For organ-transplant patients who are at risk of getting CMV from a transplanted organ, preventive therapies are available. Blood banks have screening and processing procedures that help to prevent CMV from being passed in blood products.

Reviewed by: Raluca Papadopol, MD
Date reviewed: December 2014