Treating genital herpes reduces HIV transmission.
Most people with sexually acquired HIV also have herpes simplex virus type 2 (HSV-2), the cause of genital herpes.
Co-infection with both HIV and HSV-2 is associated with increased genital HIV shedding, which may increase HIV transmission. HIV is actually shed from genital ulcers caused by HSV-2. And several HSV-2 proteins can reactivate dormant HIV infection.
Some evidence shows suppressing HSV-2 with valcyclovir (Valtrex) reduces HIV levels in the blood and in genital secretions. It was hoped that this would translate into reduced HIV progression or transmission.