Use of antiviral treatment and prophylaxis is unlikely to have a major impact on the prevalence of herpes simplex virus type 2

Background: Genital infection with herpes simplex virus (HSV) is common and can cause severe morbidity, over many years in some cases. Aciclovir provi des suppressive therapy but there is debate over the effects of its use on the spread of infection. Objectives: To explore the influence of the natural history of genital HSV and the impact of antiviral therapy. Methods: A simple mathematical model of HSV-2 transmission dynamics was dev eloped, and parameter values estimated from published data. Results: The relative durations of the risk of transmitting HSV-2 and the d uration of therapy generate a non-linear relation between the duration of a ntiviral therapy and the reduction in prevalence of infection. If there is a wide distribution of risk of HSV-2 transmission over the course of an inf ection then practicable aciclovir use is unlikely to have any great impact on disease transmission dynamics. Conclusions: There are still many uncertainties in the transmission dynamic s of HSV-2. In particular, infectiousness over the course of an infection r equires more detailed exploration. To have a significant impact on the prev alence of HSV-2 aciclovir use would have to be widespread and for a long du ration.