Child touching mom's pregnant belly

What Child Care Providers Should Know About Cytomegalovirus (CMV)

What is cytomegalovirus?
Cytomegalovirus (CMV) is a common infection caused by a virus. Most people get infected during their life, but not everyone has symptoms. Some people get very sick from CMV infections. People who are at risk include:

  • People who are immunocompromised. 
  • People who are pregnant, because CMV can harm the fetus.
  • Infants born premature or at a very low weight.

Who gets CMV and how?
CMV is a type of herpesvirus. A person’s first CMV infection is called their primary infection. People get primary CMV infections from direct contact with body fluids. Examples of body fluids are saliva, blood, and urine. Diaper changing, feeding, bathing, and other activities can spread CMV. 

CMV can spread from a pregnant person to a baby before, during, or after birth. 

CMV is tricky because the virus stays inactive, or hidden, in the body after the primary infection. This inactive stage is called a latent infection. 

CMV can reactivate, or flare-up. CMV flare-ups are not common unless someone has a weakened immune system. Think about cold sores, caused by a similar virus. After people get cold sores for the first time, the virus hides in their body. The illness can come back, usually when people are tired, sick, or stressed. The same thing can happen with CMV.

CMV is also tricky because:

  • It spreads quickly. 
  • People infected with CMV may be contagious for weeks, months, or years.
  • People can be reinfected with a different strain of CMV, similar to how people can be infected with different types of the influenza virus. 
  • There are no vaccines for CMV yet.

What are the symptoms of CMV?
A child with CMV may have:

  • Fever
  • Body aches and weakness
  • Sore throat
  • Swollen glands (lymph nodes) in the neck
  • Enlarged liver or spleen

Many children do not have symptoms of CMV infections. However, CMV can be severe, even life-threatening, for people with weakened immune systems and premature infants.

How does CMV impact infants and toddlers?
Young children can easily become infected with CMV and spread the virus.

This is because children get exposed to more viruses and bacteria over time. The body can “remember” the viruses and bacteria and use the “memory” to fight the pathogens when they come back. Infants and toddlers get sick more often because they don’t have the same immune “memory” as older children. 

Is CMV dangerous for people who are pregnant?
If a person is infected with CMV for the first time or has an active infection while they are pregnant, there is a risk they will transmit the CMV virus through their blood to the fetus. This is called congenital CMV and in some cases can be harmful to the fetus.  The best thing is to try to prevent congenital CMV infections:

  • People who are pregnant should avoid direct contact with children’s saliva and body fluids. Consider working with children ages 3 and older. 
  • Staff who are pregnant or expecting to become pregnant should consult with their health care provider about their occupational health risks.
  • Program directors might ask staff to complete health assessment forms. Directors can provide reliable information about occupational health risks. 

Should children with CMV stay home?
Most children with CMV do not need to stay home from child care. It is so common, that there are probably other children with CMV in the child care program. Keep children home if they do not feel well enough to participate or if they require more care than can be provided without impacting the care of the other children.

Most children infected with CMV get better on their own. Families should check with their child’s health care provider if they have questions or concerns about their child’s symptoms.

Tips to reduce the risk of CMV

Practicing healthy habits can reduce the risk CMV infections:

  • Practice good handwashing.
  • Wear gloves and wash hands for diaper changes and contact with body fluids.
  • Teach children to cough into their elbow and away from people.
  • Wipe noses with clean tissues, dispose of them properly, and wash your hands.
  • Don’t allow children to share food, bottles, toothbrushes, eating utensils, drinking cups, or mouthed toys.
  • Follow the routine schedule for cleaning, sanitizing, and disinfecting in Caring for Our Children Appendix K. 

Where can I get more information?

Updated July 2023, UCSF California Childcare Health Program