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Cytomegalovirus (CMV) Infections: What Parents Need to Know

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By: Mary T. Caserta, MD, FAAP

Cytomegalovirus (CMV) is a common virus that belongs to the herpes family, like the one that causes chickenpox (varicella zoster virus). CMV is the most common infection acquired before birth—known as a "congenital" CMV infection—in the United States.

Read on to learn about signs of CMV, ways to treat congenital CMV infection and what to know about CMV in pregnancy.

How does CMV affect children?

CMV infection is generally mild. Most newborns with congenital CMV infection have no signs of illness at birth and remain well. However, they are at risk of hearing loss and developmental challenges in infancy and childhood. CMV infection acquired after birth can cause serious illness in people with conditions that affect the immune system.

The virus is common in adults, too. Most people with CMV do not have signs or symptoms so they do not know that they have been infected. More than half of adults are infected with CMV by age 40.

Once a person is infected, the virus stays in their body for the rest of their life—usually in a resting or inactive state. But the virus can become active and be detected in that person's spit, urine or other body fluids. People can spread it to others through close contact. If the virus becomes active, it can cause illness if the person has a condition or takes medication that affects their immune system.

CMV disease

In some cases, CMV infection can cause serious problems. About 1 in 5 babies with congenital CMV infection will have birth defects or other long-term health issues.

  • Babies born with congenital CMV infection may have hearing changes or a learning disability.
  • Newborns may have low birth weight, jaundice (yellowing of the skin and eyes), swollen lymph nodes, a small head compared to their body, an enlarged liver or a skin rash. They may have problems throughout life such as deafness and other special health needs.
  • Infants with congenital CMV infection may not show signs of infection at birth. Still, some may develop hearing loss or other special health needs in childhood. This is not very common.
  • Teens who acquire CMV infection may have symptoms similar to infectious mononucleosis. These may include fever that lasts more than a few days, sore throat, body aches and fatigue.
  • Children with immune system compromise may have symptoms that affect their lungs, liver, kidneys, bone marrow or bowels. The infection can also cause problems for children who receive an organ transplant.

How CMV spreads

CMV infection spreads through contact with body fluids such as spit (saliva), tears, urine and blood.

Infections are spread in infants, children and adults at home or child care, including:

  • during diaper changes.
  • while bathing.
  • during close contact such as kissing, placing an infant's pacifier in your mouth or sharing food.
Ways to lower the risk of spreading CMV infection
  • Handwashing. Clean hands before and after feeding or wiping the noses/faces of infants and toddlers, changing diapers or touching objects such as pacifiers that were in contact with saliva.
  • Keep a child's pacifier out of a parent, caregiver or other child's mouth.
  • Avoid sharing cups, utensils and toothbrushes with others.

CMV can also pass from a pregnant person to the fetus through the placenta and cause congenital CMV. It can pass from a pregnant person to their infant through fluids in the birth canal during childbirth and to babies through breastmilk. Healthy newborns and infants who acquire CMV infection during or after birth usually remain well and without any signs of CMV disease.

Children who have human immunodeficiency virus (HIV) infection or whose immune system is not functioning for another reason (for example, because of cancer treatment) are at higher risk of problems if they are infected with CMV.

How is CMV diagnosed and treated?

To diagnose a CMV infection, a pediatrician or other health care clinician may order lab tests of urine, saliva, blood or other body fluids.

Fortunately, most children with CMV do not need treatment. Medical treatment is recommended for newborns with congenital CMV who have signs of illness. Even with treatment, babies with CMV infection may have or develop hearing changes or other developmental challenges.

Serious CMV infections in children with immune system compromise, such as those with HIV infection or an organ transplant, can be treated with a medicine called ganciclovir or valganciclovir. This medicine is also used to treat newborns with moderate or severe congenital CMV disease.


Many of us do not know we have a CMV infection. Even without symptoms, we can spread the virus through body fluids like urine and saliva. But there are ways to help reduce the spread of the virus to pregnant people and others who are at risk of serious illness.

More information

About Dr. Caserta

Mary T. Caserta, MD, FAAP, is a Professor of Pediatrics in Infectious Diseases at the University of Rochester Medical Center (URMC) in New York. Her early research focused on human herpesvirus research. Recently, her research has focused on viral respiratory disease. For over 10 years, she also has conducted clinical trials, including on the treatment of congenital CMV infection. Dr. Caserta is a fellow of the Infectious Disease Society of America and member of the Pediatric ID Society. Dr. Caserta is a member of the American Academy of Pediatrics Committee on Infectious Diseases.

Last Updated
American Academy of Pediatrics (Copyright @ 2024)
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
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