Cytomegalovirus (CMV) infection


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You can get CMV at any age, but many people are first infected during childhood and are unaware they've been infected.

When you develop a CMV infection for the first time, it's known as primary CMV. It's thought that 50-80 per cent of adults in the UK are infected with CMV.

Once you've been infected, the CMV virus stays in your body for the rest of your life, but in most cases it remains inactive and doesn't cause further problems.

Who gets CMV infection?

In the UK it is estimated that one to two babies in every 200 will be infected with CMV in the womb - known as congenital CMV infection.

Around 13 per cent of babies born with congenital CMV will have symptoms at birth, and a similar number of babies who don't have symptoms at birth will develop problems at a later stage.

Many babies acquire CMV infection during delivery by passage through an infected birth canal or after birth through infected breast milk – called perinatal CMV infection.

Children who have not been infected with CMV are often infected during the toddler or nursery years and most people will have been infected with CMV by the time they reach puberty.


This depends on when you first became infected with the virus.


CMV remains dormant in your body after your initial infection, but the virus can later become reactivated, particularly if your immune system is compromised, resulting in what's known as a recurrent CMV infection.

Fortunately, the risk of passing the virus to your baby during a recurrent infection is very low (about 1 percent) and the risk of serious complications is even lower.




Among these women there's about a 30 to 50 percent chance that the baby will become infected in the womb. The chance that the baby will end up with serious health problems from the virus is also much higher.

How is CMV spread?

CMV is excreted in urine, saliva, breast milk, cervical secretions and semen of infected individuals, even if the infected person has never experienced clinical symptoms.

CMV is not spread by casual contact with infected persons.

What are the signs and symptoms of CMV infection?

Most cases of CMV don't cause any symptoms and you may not even realise you're infected.

If symptoms do occur they are similar to flu symptoms and can include a high temperature of over 38°C (100.4°F), fatigue, a sore throat and swollen glands, muscle and joint pain and a loss of appetite.

These symptoms will usually last for between one and two weeks.

People with a weakened immune system may experience the most severe symptoms, including pneumonia and inflammation of the liver.

While most infants with congenital CMV infection do not show symptoms at birth, a very small number may develop psychomotor, hearing or dental abnormalities over the first few years of their life.

Symptoms of congenital CMV at birth can include jaundice (yellowing of the skin and whites of the eyes), pneumonia (lung infection), rash, an enlarged liver and spleen, low birth weight and seizures (fits).

Some of these symptoms can be treated, but some babies will develop long-term conditions as a result of the infection.

What is the treatment for CMV infection?

There is no specific treatment for CMV infection.

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