Cytomegalovirus (CMV) is a common virus that is part of the herpes family of viruses. 

It causes few symptoms in most people. If you do experience symptoms, they may be similar to flu or glandular fever, and include a high temperature (fever), sore throat and swollen glands.

Many people are first infected with CMV as a child and do not even know they have been infected. However, CMV can be caught at any age. Once you have been infected by CMV, the virus stays in your body for the rest of your life, but does not usually cause further problems.

However, CMV can sometimes recur, which can be a problem if you have a weakened immune system  due to chemotherapy, for example. If this happens, the virus can affect your organs and cause problems with vision, ulcers and pneumonia.

CMV can also cause serious problems if a woman develops a CMV infection during pregnancy, as the infection can spread to the unborn baby (known as congenital CMV).

It is estimated that one to two babies in every 200 will be born with congenital CMV in the UK. Of these, about 13% will have problems when they are born and around another 14% will develop problems later on. Problems that congenital CMV can cause include hearing loss and learning difficulties.

Read more about the symptoms of CMV.

How does CMV spread?

CMV is spread through bodily fluids, such as saliva and urine. It can be passed on through close contact with young children, such as changing nappies, or can be spread from one person to another when kissing or having sex.

Read more about the causes of CMV infections.

Can CMV be prevented?

It is not always possible to prevent the spread of CMV, and most people don't need to worry about being infected, as the infection is usually mild.

You can reduce your chances of developing an infection by practising good hygiene, such as regularly washing your hands with soap and warm water. This is especially important after changing nappies.

If you have a weakened immune system, you can take further steps to reduce your chances of infection, including taking extra care washing yourself, your clothes and your bed linen regularly.

Possible vaccines for the condition are currently being researched, but ware unlikely to become publicly available for several years.

Read more about preventing CMV.

Treating a CMV infection

As CMV causes no symptoms in most people, it is not usually diagnosed. If you are at risk of complications, a blood test can determine if you have ever had CMV or if you have recently caught it for the first time. Blood, urine and saliva swab tests can be used to determine if a newborn baby has congenital CMV.

Most CMV infections are not treated. However, if you have mild symptoms, painkillers can help reduce any pain or fever.

CMV that recurs in someone with a weakened immune system is usually treated with antiviral medicines, which slow the spread of the virus. In some cases, it may need to be treated in hospital. Some babies with congenital CMV may also receive antiviral treatment.

Read more about treating CMV.