Lowering the Risk of Passing On Genital Herpes: What Trials Show
Intimate HealthArticleHaving genital herpes doesn't mean you'll pass it on, and there are proven ways to lower the risk. In a trial of 1,484 couples, a daily antiviral pill for the partner with herpes cut new infections roughly in half overall, from 3.6% to 1.9% over 8 months. Across 6 studies, people who always used condoms had about 30% lower risk of catching it. Here is how the two fit together.
In this article
A herpes diagnosis often brings one worry above all: passing it to a partner. The virus can spread even when there are no symptoms.1 But two well-studied steps lower the risk.
A daily antiviral pill
In a trial of 1,484 couples where one partner had genital herpes and the other didn’t, the partner with herpes took valacyclovir 500 mg once a day or a placebo for 8 months.2 Both partners were offered condoms and safer-sex advice.2
| Partner who didn’t have herpes | Antiviral | Placebo |
|---|---|---|
| Caught herpes, any kind | 1.9%2 | 3.6%2 |
| Got symptomatic herpes | 4 of 7432 | 16 of 7412 |
The antiviral also cut how often the virus could be detected on the genitals, from 10.8% of days to 2.9%, and outbreaks fell from 0.40 to 0.11 a month.2
Condoms
A pooled analysis of 6 studies with 5,384 people looked at condom use and catching herpes.3
- People who used condoms every time had about 30% lower risk than people who never did.3
- Each unprotected sex act raised the risk.3
- Protection was similar for women and men.3
Condoms give moderate protection against herpes, less than for some other infections, because the virus can be on skin a condom doesn’t cover.31
Putting it together
UK health advice to lower the chance of passing on herpes:1
- Use a condom every time, for vaginal, anal or oral sex.
- Avoid sex during an outbreak, including when you feel the tingle or itch that signals one is coming.
- Don’t share sex toys.
Adding a daily antiviral is worth discussing with your clinician, especially in a long-term relationship with a partner who doesn’t have herpes.2 See how often genital herpes comes back and herpes blood test limitations.
Try: “I have genital herpes and my partner doesn’t. Would daily antiviral treatment make sense for us, and what else lowers the risk?”
Down There, Decoded covers repeat infections and partners in Chapter 7, “Here We Go Again,” in a section called “The Partner Question.” Its Down-There Log records each outbreak with dates and possible triggers, so you and your clinician can see the pattern. See the book.
This article is for general educational purposes only and is not medical advice. It isn't a substitute for diagnosis or treatment from a qualified healthcare professional who knows your health history. Antiviral medicines need a prescription. If you're pregnant and you or your partner has genital herpes, tell your maternity team. Girl Playbook does not endorse any specific product, test, or provider.
Girl Playbook sells this book. It provides education and worksheets, not individualized medical care.
Sources
The research behind this article, in the order it’s cited. How we source our articles.
- NHS, 2026Genital herpes (opens in a new tab)abc
- New England Journal of Medicine (abstract via PubMed), 2004Once-daily valacyclovir to reduce the risk of transmission of genital herpes (opens in a new tab)abcdefgh
- Archives of Internal Medicine (via PubMed Central), 2009A pooled analysis of the effect of condoms in preventing HSV-2 acquisition (opens in a new tab)abcde
Spotted something out of date? Tell us and we’ll check it.
