What is CMV?

CMV is a very common viral infection, especially in young children and teenagers. Most adults have had the infection at some point. CMV may stay in a person’s system for years, but the person remains well and knows nothing about it.

Most people have no symptoms. For women who develop the illness while pregnant, there is a small risk that their baby will be born with a permanent disability.

What causes CMV?

CMV is transferred from person to person through bodily fluids. Most commonly, this is through a child's saliva. The virus is also found in other body fluids such as breast milk, blood, vaginal secretions or semen. The virus can also be spread from a pregnant women to her unborn child.

CMV symptoms

The symptoms of CMV can vary. Some people have no symptoms. Others might have symptoms like:

• fever
• tiredness
• sore throat
• swollen glands
• abdominal pain

Some people can get seriously ill. Most people who become seriously ill have problems with their immune systems, either due to a condition like HIV or due to being on chemotherapy.

If a woman is newly infected with CMV while pregnant, there is a risk her unborn baby will also become infected (congenital CMV).

The vast majority of babies with congenital CMV remain well all their life. A few develop long-term problems. The most common problem is hearing loss.

CMV diagnosis

If you're worried about the possibility of having CMV, you can have two tests:

• a test for the virus itself from fluids such as urine
• a blood test for an immune response to the virus

CMV testing is recommended for pregnant women who develop a viral illness or when ultrasound shows a foetal abnormality.

CMV treatment

Most people will recover well from CMV without treatment. Pregnant women or people with immune problems should see their doctor for advice about the risks and benefits of treatment in their specific situation. There are treatments, but they are still thought to be experimental.

CMV prevention

Women who are pregnant or considering becoming pregnant should take precautions to avoid being infected with CMV from young children. If you are pregnant and come in close contact with young children, then:

• wash and dry your hands after touching young children
• wear gloves while changing nappies if you can
• wash your hands especially well after changing nappies or handling items such as toys that might have traces of saliva or urine
• avoid sharing food or toothbrushes
• take care when kissing babies to avoid contact with their saliva
• clean toys or surfaces that might have come into contact with their saliva, urine or body fluid

There is no vaccine to prevent CMV infection.