This section of the website is for UK healthcare professionals only. If you are not a healthcare professional, please click here.
This section of the website is for UK healthcare professionals only. If you are not a healthcare professional, please click here.

This section of the website is for members of the public. If you are a healthcare professional,visit the HCP section of the site. This website is not intended to replace the advice of a healthcare professional. You should consult your doctor or another suitably trained healthcare provider when considering what type of treatment is most appropriate for you.

What is Cytomegalovirus (CMV)?

CMV is a very common virus that is part of the herpes simplex family. Between 50 - 80% of adults in the UK are thought to have the virus but most people don’t know they have it.1 You can get CMV at any age, but many people are first infected during childhood and are unaware they have it.2

CMV can spread very easily and is predominately transmitted through bodily fluids such as blood, saliva, urine and breast milk. Once infected, your body retains the virus for life, however most people don't even know they have CMV because in most cases the virus remains inactive and rarely causes problems in healthy people.2

Haematopoietic stem cell transplants (HSCTs)

Haematopoietic stem cell transplants (HSCT) procedures, commonly known as blood or bone marrow transplants replace damaged blood cells with healthy ones. HSCTs are mostly given to treat blood cancers such as leukaemia and myeloma, and for other blood disorders like sickle cell anaemia, but increasingly non-blood related disorders like multiple sclerosis. HSCTs are broadly divided into two main groups:3

  • Autologous transplantation- uses the patients’ own cells which are harvested prior to high-dose therapy. It enables the patient to be treated with doses of chemotherapy which are higher than would be possible without subsequent replacement of the harvested cells, because the therapy destroys the patient’s remaining stem cell tissue.3
  • Allogeneic transplantation- harvests the stem cells from a donor and is used to treat carefully selected patients with a range of malignant and non-malignant blood-related disorders and other specific disorders of the immune system. It involves replacing the bone marrow stem cells of a patient following high-dose therapy, with stem cells from a tissue-type matched or mismatched donor.3

CMV in allogeneic-HSCT patients

Both recipients of autologous and allogeneic HSCTs who have dormant underlying CMV are at risk for CMV reactivation, but where patients have received the stem cells from others (allogeneic) they are at greater risk than when a patient’s own cells have been used (autologous).4

Allogeneic-HSCT patients are at risk of viral infections such as CMV due to the necessary use of immunosuppressive agents needed to treat or prevent graft vs host disease. CMV disease, resulting from CMV replication through reactivation or new infection is a serious and potentially life threatening complication for HSCT recipients. The risk of developing or reactivating CMV infection depends on the CMV-serostatus (+/-) of the donor and recipient of the transplant.4

Further information about CMV

Find out more about CMV at, the official website of the National Health Service in England.

Further information about stem cell transplants

Find out more about stem cell transplants at, the official website of the National Health Service in England.

Contact Information

Our address for correspondence is:
Hertford Road,
EN11 9BU

Alternatively you can telephone: 01992 467272
Or Email:

Reporting side effects: If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in the package leaflet. You can also report side effects directly via the Yellow Card Scheme at or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects, you can help provide more information on the safety of this medicine.


  1. Thomson KJ, Peggs KS et al. Allogeneic transplantation in the UK: an aggregation of marginal gains? Br J Haematol. 2013;163(2):149–159.
  2. NHS. Report warns of threat to unborn babies from CMV virus. Available at:
  3. NHS. Cytomegalovirus. Available at:
  4. NHS Commissioning Board. Clinical Commissioning Policy: Haematopoietic Stem Cell Transplantation. Available at:
  5. Ljungman P, Hakki M, Boeckh M. Cytomegalovirus in hematopoietic stem cell transplant recipients. Hematol Oncol Clin North Am. 2011;25(1):151–169.