Clinical and Virologie Efficacy of Herpes Simplex Virus Type 2 Suppression by Acyclovir in a Multicontinent Clinical Trial

Acyclovir suppressive therapy (400 mg twice daily) reduces herpes simplex virus (HSV) type 2-associated genital ulcer disease and lesionai HSV shedding. In an international trial of acyclovir for suppression of HSV type 2 to prevent human immunodeficiency virus (HIV) acquisition (HIV Prevention Trials Network 039), acyclovir had a smaller effect on the frequency of genital ulcer disease as well as a smaller effect on the frequency and quantity of lesional HSV DNA in Af-rican women and Peruvian men, compared with its effects in men in the United States. The observed regional varia-tion in the clinical and virologic efficacy of acyclovir for HSV suppression warrants further evaluation of determinants of responses to acyclovir. (ClinicalTrials.gov identifier: NCT00076232.)