You can’t catch CMV from simply being in the same room as someone with the virus. It is spread through bodily fluids, so the chance of catching it through casual contact is very low. However, pregnant women need to take care, particularly if they work with young children or have very young children at home.
This section explains how CMV is spread, how it is transmitted to an unborn baby, gives information about breast feeding and outlines the risks of your child passing on CMV if they are infected.
How is CMV spread?
CMV is found in bodily fluids, including urine, saliva, blood, mucus and tears. It is spread through close contact with bodily fluids. The main way pregnant women catch CMV is from small children’s saliva and urine. So women who work with children, or who have a family already, need to be especially careful during pregnancy. There are some simple measures that can reduce the chance of catching CMV infection, these are described in the Risk Reduction section.
How long does the virus stay on surfaces?
The CMV virus survives on different surfaces for different periods of time. For example, it survives at least 15 minutes on hands, longer on plastic and shorter on wood.
Studies suggest that it can survive on surfaces long enough for people to pick it up. However, direct transmission through person-to-person contact is still considered the most likely way for people to catch it.
Is it safe to breast feed my baby?
CMV can be passed through breast milk. However, if your baby is born full term, and you have CMV, they will not develop any problems if you are breast feeding.
Babies who have been infected with CMV in the womb may also be re-infected with a new strain of CMV in the breast milk. It is thought that this does not cause further problems. The benefits of breast milk are numerous and well documented and if you wish to breast feed your baby you should be encouraged to continue.
Should I continue to breast feed if my baby is being treated with anti-viral medication?
Yes, you can continue to breast feed if your baby is being treated with anti-viral medication.
My child has congenital CMV, are other people at risk of CMV infection from them?
If your child was born with congenital CMV and still has an active infection then others can catch it through close contact with their bodily fluids.
If I have a baby with congenital CMV, could my next baby also have congenital CMV?
There is little information about the risks of having a second child with congenital CMV.
The risk of having a second baby with CMV symptoms as a result of your original virus reactivating is actually very low – around 0.01% or 1 in 10,000. In general, women are advised to wait a year from delivery before trying for another baby to reduce this risk as far as possible.
However, there is still a risk of being re-infected with a different strain of CMV and it is therefore important that all pregnant women practice simple hygiene precautions even if they have had CMV before.
Should my child’s nursery or school take special precautions?
Around a quarter of young children will already be carrying the virus. There is therefore no need for education settings to treat your child any differently from other children. Any of the children they work with could have an active CMV infection.
All nurseries and schools should ensure that staff are practicing good hygiene precautions with all children. This means washing hands after changing nappies, not sharing cups and cutlery with children and washing toys regularly. These simple hygiene measures have been shown to reduce the risk of catching CMV.
Should I find out if my child is still shedding the virus?
Most children with congenital CMV will shed the virus (which means it will be present in their bodily fluids) through toddler and preschool age. Infants and children who catch CMV after they are born will also shed CMV. The virus will affect each child differently and the length of viral shedding can range from just a few months to eight years of age, and possibly longer.
It is not necessary to keep checking if your child still has the virus active in their urine or saliva because its presence does not appear to influence or predict problems. Furthermore, schools and nurseries should not require your child to be tested for CMV shedding before admitting them. Your child should not be denied access to nursery or education because of the diagnosis of congenital CMV infection.
Can CMV be transmitted through egg or sperm donation during fertility treatment?
There is little evidence on this. CMV has been identified in sperm, but the risks of transmitting CMV through donor sperm have not been quantified. It is not known whether CMV can be transmitted via egg donation and whether the risks are greater or less than with sperm donation. Despite a relatively low risk, congenital CMV infection from donated sperm cannot be ruled out.