What Is Cytomegalovirus (CMV)?

What Is Cytomegalovirus (CMV)?

This article is for people who have cytomegalovirus (CMV) or are at risk for getting it, or anyone who's interested in learning more about CMV. The goal of this activity is to help people engage in shared decision-making with their doctor about CMV.

You will learn about:

  • What CMV is and how it can stay in your body

  • Who can get CMV  

  • CMV symptoms and complications (additional problems)

  • How CMV can spread

  • Talking to your doctor about CMV

Test Your Knowledge

CMV Is a Common Virus in Humans

Cytomegalovirus, or CMV, is a type of virus commonly found in humans. CMV is so common, in fact, that nearly 1 out of every 3 kids in the United States will be infected by the time they're 5, and over half of all people will be infected by the time they're 40.

CMV is related to the viruses that cause chicken pox, shingles, cold sores, and mononucleosis ("mono"). Like these other viruses, once you get CMV, it stays in your body for your lifetime.

Dormant or Active?

If you're a fairly healthy adult, you may not even know you've been infected with CMV. And once you do have it, CMV will likely stay dormant (inactive) in your body.

But CMV can become active again if your immune system -- your body's natural defense system -- is weakened. This can happen if you're taking certain medicines, during treatment for cancer, if you're living with certain health conditions such as HIV, or after an organ, bone marrow, or stem cell transplant.

Who Can Get CMV and How?

Anyone at any age can get CMV. Types of CMV infection include:

  • Primary, or the first time you get CMV

  • Reinfection when you get infected again, but with a different strain (variety) of the virus

  • Reactivation when an earlier CMV infection in your body becomes active again after lying dormant 

  • Congenital when a baby gets CMV before being born due to their mother's primary infection, reinfection, or reactivation during pregnancy

  • Perinatal when a baby gets CMV from their mother during birth or shortly afterward, including from breast milk

Symptoms and Complications

Most adults who have a healthy immune system and get a primary CMV infection don't know they have it because they don't feel sick and may have few or no symptoms. But CMV can cause serious symptoms and complications (additional problems) for babies and people who have a weakened immune system.

In adults with a healthy immune system who do have symptoms, they may be mild and can include:

  • Fatigue (tiredness)

  • Fever

  • Sore throat

  • Swollen glands

  • Muscle aches

While rare, CMV can also sometimes cause complications in adults with a healthy immune system, including heart or brain inflammation (swelling), digestive system and liver problems, or illnesses caused by other viruses, such as mononucleosis.

People Who Have a Weakened Immune System

CMV can cause serious symptoms and complications for people who have a weakened immune system. For some -- especially those who've had an organ, stem cell, or bone marrow transplant -- it can even be deadly.

Many complications are due to inflammation and can include problems with your:

  • Eyesight, including vision loss

  • Liver, stomach, intestines, and esophagus (the muscular tube that connects your mouth to your stomach)

  • Lungs, including pneumonia  

  • Brain and nerves

  • Skin, including rashes and lesions

Congenital CMV

About 1 out of every 200 babies is born with congenital CMV. Most will have no symptoms at birth, but CMV can cause serious complications for babies. Even those who appear healthy at birth can develop complications months or years later.

Symptoms and complications of congenital CMV can include:

  • Premature birth

  • Low weight at birth

  • Pneumonia

  • Yellow skin and eyes (jaundice)

  • Liver and spleen problems

  • Hearing or vision loss

  • Rashes and/or purple spots or skin patches

  • A small head (microcephaly)

  • Growth or learning problems

  • Cerebral palsy or trouble with muscle tone and coordination

  • Seizures

How CMV Is Spread

CMV is spread from person to person. When CMV is active in your body, you can easily pass the virus to others through your body fluids, such as blood, saliva, tears, urine, semen, vaginal fluids, and breast milk.

This can happen through:

  • Direct physical contact, including sexual activity

  • Pregnancy, birth, or breast milk

  • Blood transfusions and organ, bone marrow, or stem cell transplants

Casual contact, such as hugging or holding hands, very rarely spreads CMV.

Talking to Your Doctor About CMV

Talk to your doctor about getting tested for CMV, especially if you have symptoms and a weakened immune system or are pregnant or thinking about getting pregnant. They may recommend a test that checks your blood or other body fluids.

If you're pregnant, your doctor may recommend you have certain prenatal tests (before your baby is born). Babies can also be checked for congenital CMV by testing their urine, saliva, or blood within 3 weeks after they're born. If your doctor thinks you may have a CMV infection, your baby should be tested as soon as possible.

Dr Megan H. Pesch talks about CMV infection, how the virus can stay in your body, and what that may mean for you and your family.

Questions to Ask Your Doctor

Questions you can ask your doctor about CMV can include:

  • What should I know about CMV?

  • Is there anything I should know if I have a weakened immune system?

  • What about if I'm pregnant, trying to get pregnant, or have a baby?

  • Are there any CMV symptoms that I should look out for?

  • Where can I find more information and resources?

Test Your Knowledge

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You have successfully completed the program What Is Cytomegalovirus (CMV)?

View Additional Materials on this topic that you may find useful:

Cytomegalovirus (CMV) and Congenital CMV Infection

Babies Born With Congenital Cytomegalovirus (CMV)

Resources for Pregnant Women and Parents

Patient Handout

Authors and Disclosures


Megan H. Pesch, MD, MS

Assistant ProfessorDivision of Developmental and Behavioral PediatricsUniversity of Michigan Medical School.

Disclosure: Megan H. Pesch, MD, MS, has disclosed the following relevant financial relationships: Served as an advisor or consultant for: DiaSorin Molecular; ModernaTx.

Clinician Reviewer

Karen Badal, MD, MPH

Senior Medical Education Director, Medscape, LLC.

Disclosure: Karen Badal, MD, MPH, has disclosed no relevant financial relationships.


Anita A. Galdieri, PharmD, RPh

Associate Director, Content Development. Medscape, LLC

Disclosure: Anita A. Galdieri, PharmD, RPh, has disclosed no relevant financial relationships.


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