Genital Herpes: Can Daily Treatment Reduce Transmission?

Why can genital herpes spread without visible sores?

The distinction between symptom relief and transmission prevention matters when assessing herpes products. In an October 1 warning letter to Amazon, the FDA cautioned that unapproved sexually transmitted infection remedies can create false reassurance and delay appropriate care. The agency stated that it has approved no over-the-counter drug to treat or prevent an STI. That concern makes evidence about partner protection especially relevant. [FDA warning letter](https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/amazoncom-inc-736006-10012026)

WHO explains that herpes can spread through contact with skin that appears normal, although transmission risk is greatest when sores are present. Both HSV-1 and HSV-2 can cause genital infection. Treatment can control symptoms, but it does not cure the infection. Consequently, judging infectiousness solely by whether a sore has healed can miss periods when transmission remains possible. [WHO herpes fact sheet](https://www.who.int/news-room/fact-sheets/detail/herpes-simplex-virus)

How much can daily valacyclovir reduce HSV-2 transmission?

The evidence includes an established trial published in the New England Journal of Medicine in 2004. Researchers followed 1,484 monogamous heterosexual couples without immune compromise; one partner had symptomatic genital HSV-2 and the other was susceptible. The infected partner received daily valacyclovir or placebo for eight months. Both groups received safer-sex counseling and were offered condoms. This was a study of medication added to prevention support. [Corey and colleagues](https://www.nejm.org/doi/full/10.1056/NEJMoa035144)

HSV-2 acquisition occurred in 14 susceptible partners in the valacyclovir group and 27 in the placebo group, corresponding to 1.9% and 3.6%. The absolute difference was approximately 1.7 percentage points during follow-up. Protection was incomplete, and these figures describe this particular population and observation period. They should not be presented as a universal annual transmission risk or evidence that medication makes every sexual encounter risk-free. [Trial results](https://www.nejm.org/doi/full/10.1056/NEJMoa035144)

What prevention plan should couples discuss with a clinician?

CDC guidance distinguishes daily suppression from short treatment courses taken during outbreaks. Suppression reduces recurrent episodes by 70–80% among people with frequent recurrences, but that statistic measures outbreaks, not transmission. Whether daily treatment is appropriate depends on the infection type, symptoms, and individual circumstances. [CDC treatment guidance](https://www.cdc.gov/std/treatment-guidelines/herpes.htm)

Condoms reduce transmission risk but cannot cover every potentially infectious area. CDC also recommends avoiding sexual contact when sores or warning symptoms, such as tingling, occur. Discussing the diagnosis with partners supports informed decisions. Fewer outbreaks can improve quality of life, while continued precautions address the remaining possibility of transmission between episodes. [CDC prevention counseling](https://www.cdc.gov/std/treatment-guidelines/herpes.htm)