Background. Tenofovir is a potent anti-human immunodeficiency virus (HIV) agent that decreased risk of herpes simplex virus type 2 (HSV-2) acquisition in HIV pre-exposure prophylaxis trials. Whether tenofovir has utility in established HSV-2 disease is unclear. Methods. We randomized immunocompetentwomen with symptomaticHSV-2 infection to oral tenofovir disoproxil fumarate (TDF)/placebo vaginal gel, oral placebo/tenofovir (TFV) vaginal gel, or double placebo (ratio 2:2:1) in a one-way cross-over trial. Women collected genital swabs twice daily for HSV PCR during 4-week lead-in and 5-week treatment phases. The primary intent-to-treat end point was within-person comparison of genital HSV shedding and lesion rates. Results. 64 women completed the lead-in phase and were randomized. Neither TDF nor TFV gel decreased overall shedding or lesion rate in the primary analysis; TFV gel decreased quantity of HSVDNAby-0.50 (-0.86-0.13) log10 copies/mL. In the per-protocol analysis, TDF reduced shedding (relative risk [RR] = 0.74, P =.006) and lesion rates (RR = 0.75, P =.032); quantity of virus shed decreased by 0.41 log10 copies/mL. Conclusions. Oral TDFmodestly decreasedHSV shedding and lesion rate, and quantity of virus shed when used consistently. Vaginal TFV gel decreased quantity of virus shed by 60%. In contrast to effects onHSV-2 acquisition, tenofovir is unlikely to provide clinically meaningful reductions in the frequency of HSV shedding or genital lesions. Clinical Trials Registration. NCT01448616.
