Because CMV is a very easy virus to transmit—it can be spread through saliva—there is no easy way to prevent being infected with this virus. However, there are ways to prevent CMV from causing active disease and illness:

Preventing CMV Disease
	Keep your immune system healthy. CMV disease, especially CMV retinitis, can occur once the immune system becomes seriously damaged (less than 100 CD4 cells). Using HIV drugs can help protect the immune system and, as a result, help prevent CMV from causing active disease.
	See an ophthalmologist (eye doctor) on a regular basis. If you have a suppressed immune system, you should see an ophthalmologist on a regular basis, usually every three to six months. An ophthalmologist can examine the back of your eyes for any signs of CMV. This is very important, as an ophthalmologist can diagnosis CMV—and recommend treatment—before permanent damage to eyesight occurs.

In the past, experts recommended the use of oral valganciclovir (Valcyte) to prevent CMV in people with CD4 counts below 50 cells. This is no longer recommended by the DHHS, because Valcyte prophylaxis is expensive, can cause CMV to become resistant to the medication and prevent its use as treatment and there is a lack of clinical trial data showing that it prolongs survival in people living with HIV.