Cytomegalovirus infection

Cytomegalovirus is a common virus that stays in the body for life once you’re infected. While most healthy people never know they have it, the virus can cause serious problems for pregnant women, newborns, and those with weakened immune systems.

Table of contents

• What is cytomegalovirus
• Who is affected by CMV
• Signs and symptoms
• How CMV spreads
• Testing and diagnosis
• Treatment and recovery
• Prevention

What is cytomegalovirus

Cytomegalovirus, or CMV, is a common virus that belongs to the herpes virus family.^[1] The virus has the largest genetic material of any herpes virus and is found worldwide.^[3] CMV is extremely common—in the United States, nearly 1 in 3 children is already infected by age 5, and over half of adults have been infected by age 40.^[4] Some estimates suggest that up to 90% of all people will be infected by age 80.^[2]

Once CMV enters a person’s body, it stays there for life and can reactivate. A person can also be infected again with a different strain of the virus.^[4] After the initial infection, the virus becomes inactive and remains dormant in the body, typically in certain white blood cells called monocytes (a type of immune cell).^[3] When the immune system is weakened, the virus can become active again and cause illness.

Who is affected by CMV

While CMV can infect anyone, most people don’t have symptoms. The virus is most dangerous for certain groups of people.^[2]

Pregnant women and newborns are a major concern. If a woman gets cytomegalovirus during pregnancy or shortly before getting pregnant, she can pass the virus through the placenta (the organ that connects mother and baby during pregnancy) to the developing baby. This can increase the risk of pregnancy loss or the baby being born with health problems.^[2] When a baby is born with a CMV infection, it is called congenital CMV (present at birth). About 1 in 200 babies is born with congenital CMV infection, and about 1 in 5 of these babies will have birth defects or other long-term health problems.^[4] CMV is the most common infectious cause of birth defects in the United States.^[4]

People with weakened immune systems face serious risks from CMV. This includes people living with HIV or AIDS and those who have had an organ or stem cell transplant.^[2] If you’re taking immune-suppressing medications for a transplant, your immune system can’t easily fight off infections like cytomegalovirus. While most people can fight off CMV without symptoms, a new or reactivated infection can cause serious complications in someone with a weakened immune system, including severe organ damage and even organ rejection.^[2]

You’re at higher risk for cytomegalovirus if you are under the age of 5, work with or live with children under the age of 5, have a compromised immune system, or live in close contact with many other people.^[2]

Signs and symptoms

Most people with CMV show no signs or symptoms and aren’t aware that they have been infected.^[4] The symptoms vary greatly depending on whether the person has a healthy or compromised immune system and whether the infection is present at birth or happens later in life.

Symptoms in healthy people

Most people who have a healthy immune system don’t get symptoms of CMV.^[2] When symptoms do appear, they are usually mild and can include fever, sore throat, fatigue, and swollen glands.^[4] Some people may develop symptoms similar to mononucleosis (an infection that causes extreme tiredness), including extreme tiredness, muscle aches, sweating, headache, sore throat, swollen lymph nodes, and rash.^[2] These symptoms usually get better without treatment within about 3 weeks.^[7] Occasionally, CMV can cause mononucleosis or hepatitis (liver problems).^[4]

Symptoms in people with weakened immune systems

If you have a weakened immune system, you might get a new CMV infection or have a previous infection that reactivates when your body is no longer able to fight it off easily. Symptoms depend on what part of your body the virus infects and could include fever, fatigue, shortness of breath, difficulty breathing, blurry vision, diarrhea (possibly with blood), belly pain, trouble swallowing or painful swallowing because of ulcers in the mouth or esophagus, confusion, and muscle weakness.^[2][6] In people who have advanced HIV, CMV can cause an eye infection called retinitis (inflammation of the retina), which may lead to blindness.^[6]

Symptoms in babies with congenital CMV

Most babies with congenital CMV do not have symptoms of the infection at birth.^[5] However, some babies will show signs of the infection at birth or over time. These symptoms may include premature birth, low birth weight, small size, liver enlargement and jaundice (yellowing of the skin and eyes), spleen enlargement, lung infection, anemia, purple skin blotches or rashes, seizures, hearing loss, small head compared to body size, and developmental delays.^[5] Babies born with CMV can have brain, liver, spleen, lung, and growth problems.^[4] The most common long-term health problem in babies born with CMV infection is hearing loss, which may be detected soon after birth or may develop later in childhood.^[4]

How CMV spreads

CMV spreads from person to person through body fluids. These include blood, saliva, urine, semen, breast milk, tears, and mucus.^[1][4] The virus is found in bodily fluids and can be easily spread in households and in daycare centers.^[5]

Children are a common source of CMV. The virus can stay in a child’s body fluids for months after the infection. People who are often around young children are more likely to get infected.^[4] An infected person can spread CMV from direct contact with saliva or urine, especially from babies and young children, through sexual contact, from breast milk to nursing infants, through transplanted organs and blood transfusions, and during pregnancy.^[4]

A pregnant woman can transmit the virus to the developing baby during pregnancy. An infant can also become infected during delivery or shortly afterward, including through breast milk.^[1] CMV can also be transmitted at delivery or through breast milk, but these infections usually do not cause illness in a full-term baby. Premature babies, however, are at greater risk for health complications from CMV transmission through breast milk.^[5]

Testing and diagnosis

Healthcare providers can order blood tests to identify CMV infection in adults who have symptoms.^[4] Lab tests of blood, saliva, and urine can be done to find out if you have a CMV infection.^[1] Blood tests can find proteins called antibodies (substances the immune system makes to fight infection) that the immune system makes in response to a CMV infection. These proteins can linger in the blood for months to years after an infection.^[8]

For newborns, blood is not the best fluid to test. Saliva or urine tests are preferred for newborns. These tests must be done within 2 to 3 weeks of birth to confirm if the baby has congenital CMV.^[4]

Most often, pregnant women aren’t tested for CMV.^[8] But if you’re pregnant, testing may be recommended if you’re exposed to someone who is ill from CMV, you get symptoms such as fever, headache, fatigue, sore throat, and swollen glands, an ultrasound imaging test suggests that your unborn baby might have a CMV infection, or you have a weakened immune system.^[8] If testing spots antibodies that suggest you’ve had a recent CMV infection, more testing is recommended. If your healthcare professional finds a new CMV infection while you’re pregnant, a prenatal test called amniocentesis (removal of fluid from the womb for testing) may be recommended to find out whether the unborn baby has been infected.^[8]

Treatment and recovery

Most often, healthy people don’t need treatment for CMV infections.^[1] Healthy people who are infected with CMV usually do not require medical treatment. The body should be able to control the infection on its own, and the signs of infection are treated as they happen.^[14] Because CMV is a virus, antibiotics will not work against it and are not prescribed. Acetaminophen or ibuprofen may be given for fever, sore throat, or headache.^[14]

Medications called antivirals (drugs that fight viruses) are available to treat CMV infection in people who have weakened immune systems and babies with signs of congenital CMV at birth.^[4] The drug of choice for the treatment of CMV disease is intravenous ganciclovir (given through a vein), although valganciclovir may be used for less severe CMV treatment in selected cases.^[9] These medications weaken the virus and lower the chance of serious problems, but they do not cure the CMV infection.^[4]

For babies with congenital CMV, valganciclovir is an antiviral that might improve hearing and developmental outcomes. It can have serious side effects and has only been studied in babies with signs of congenital CMV infection.^[4] Infants with life-threatening symptoms are recommended to receive 2 to 6 weeks of intravenous ganciclovir and then switch to oral valganciclovir, and those without life-threatening symptoms are recommended to use oral valganciclovir during the entire 6-month period.^[13] During antiviral drug treatment, blood tests are performed to identify side effects like low white blood cell counts, low platelet counts, kidney failure, and liver problems.^[13]

An antiviral medication may be used to treat a cytomegalovirus infection in people whose immune systems are weakened or for transplant patients. These people usually need to be in the hospital.^[14] Additionally, cellular therapy (treatment using cells) may be used to treat CMV in patients with a weakened immune system. Specialized immune cells have been successfully used to treat CMV without the need for potentially toxic antiviral medications.^[14]

Prevention

You can lower your chances of getting CMV by reducing contact with saliva and urine from babies and young children.^[4] The best way to lower the chance of getting cytomegalovirus during pregnancy is to practice good hygiene. Proper hand washing with soap and water is effective in removing the virus from the hands.^[5]

To prevent CMV infection, make sure you:

• Wash your hands often with soap and water, especially after changing diapers, feeding young children, wiping their nose, or helping a child to use the toilet.^[1][4]
• Do not share food, utensils, cups, or pacifiers with a child.^[4]
• Regularly wash toys or other items that may have young children’s saliva or urine on them.^[7]
• Avoid kissing young children on their mouth—forehead kisses are great instead.^[18]
• Don’t touch your face after handling used tissues or diapers.^[1]

Although an infected person may transmit the virus at any time, proper hand washing with soap and water is effective in removing the virus from the hands.^[5] Women who have young children at home or work with young children may be at higher risk of CMV during pregnancy.^[18]

There is currently no vaccine for CMV.^[7] However, vaccines for CMV are under development.^[20]