Acyclovir to reduce HIV-1 transmission from people coinfected with HIV-1 and HSV

Around 60–90% of people infected with HIV-1 are seropositive for herpes simplex virus type 2 (HSV 2). There is evidence that coinfection with HSV-2 increases the infectiousness of HIV-1 and that treatment for HSV-2 reduces plasma HIV-1 RNA levels. Now, a trial in southern and East Africa has confirmed that treatment with acyclovir reduces HIV-1 RNA levels but does not prevent HIV-1 transmission.

The study included 3,408 heterosexual couples at 14 sites in seven African countries. In each couple one partner was coinfected with HIV-1 and HSV-2, and the other partner was not infected with HIV-1. The HIV-1 infected partners were not taking antiretroviral therapy at the time of enrolment. Randomization of infected partners was to acyclovir 400 mg twice daily or placebo. There were 132 HIV-1 seroconversions. Among these, 84 were shown by viral sequencing to be within-couple infections; 41 in the acyclovir group and 43 in the placebo group, a nonsignificant difference. Acyclovir reduced mean plasma concentration of HIV-1 RNA by 0.25 log10 copies per mL, and the risk of HSV 2-positive genital ulcers by 73%. There were no serious adverse events related to acyclovir.

Treatment of coinfected partners with acyclovir reduced plasma HIV-1 RNA levels and the risk of HSV-2-positive genital ulcers but did not reduce inter-partner HIV-1 transmission.

Celum C et al. Acyclovir and transmission of HIV-1 from persons infected with HIV-1 and HSV-2. NEJM 2010;362:427–439.