HIV infectiousness reduced by anti-herpes drugs

Many people living with HIV are also infected with HSV-2, which is the major cause of genital herpes. It is already known that the risk of transmitting HIV is greater when the HIV-infected person has genital ulcers caused by HSV. Studies of HIV/HSV-2 co-infected persons have also shown that HIV levels are increased during genital HSV reactivation.

In a pilot study of the effect of HSV-2 suppression on levels of HIV infectiousness, Connie Celum and a team of researchers at the University of Washington and at Impacta, in Lima, Peru looked at the effect of daily HSV suppressive treatment in a small group of HIV/HSV-2 co-infected men who have sex with men.

Twenty men aged 22 to 41 enrolled in this trial, in Peru. The men studied had no prior antiretroviral therapy and were not currently receiving antiretroviral therapy for HIV infection. Subjects were randomly assigned to the anti-HSV drug, valacyclovir 500 mg, twice daily or matching placebo for initial treatment. After eight weeks subjects then crossed over to the alternative treatment (placebo or valacyclovir) for eight weeks, after a washout period. Participants visited the clinic three times a week during each treatment arm. At each visit, rectal secretions were collected and weekly blood samples were obtained to determine levels of HIV.

Researchers found a 50% reduction in levels of HIV in blood and a 30% percent reduction in rectal fluids during the 8 weeks when the HIV/HSV-2 co-infected men received valacyclovir to suppress reactivation of HSV. This reduction in HIV levels could have a significant impact on transmission of HIV. Since the only intervention was daily valacyclovir to suppress HSV, this study adds weight to the other evidence that HSV-2 reactivation increases HIV replication.