You can sharply lower the odds of passing herpes to a partner, though not to zero, by combining daily suppressive antiviral medication, consistent condom use, avoiding sex during outbreaks, and honest disclosure. Suppressive valacyclovir alone cuts HSV-2 transmission by about 48% in studies, and stacking these methods protects best, including on days with no symptoms.
about 12%
but well controlled
| Item | Value |
|---|---|
| Adults 14–49 with HSV-2 | ~1 in 8 — about 12% |
| Unaware they have it | ~87% |
| Daily antivirals cut spread | ~50% |
| Cure | none — but well controlled |
How do you actually prevent herpes transmission?
Herpes spreads through skin-to-skin contact with a sore, with genital fluids, or with saliva when oral HSV-1 is involved CDC. It can pass even when there's no sore in sight. So prevention is a few habits layered together, each one shaving off a portion of the risk.
Here are the methods that work, roughly in order of impact:
- Daily suppressive antivirals — taken every day by the partner who has herpes, these reduce both outbreaks and the silent shedding that drives most transmission. In a randomized trial of couples where one partner had HSV-2 and the other didn't, daily valacyclovir lowered transmission by about 48% Corey et al., NEJM. That's the evidence behind taking medication for a partner's sake.
- Avoiding sex during outbreaks — the risk of passing herpes is highest when a sore is present or coming on (the tingling, itching, or burning that precedes a lesion). Skip genital and oral contact from the first warning sign until the area has fully healed.
- Consistent condom use — condoms cut HSV-2 transmission but don't erase it, because they only cover so much skin.
- Disclosure — telling a partner lets them make informed choices and stay alert to symptoms. It also makes the other steps possible, since suppressive therapy and condom use are joint decisions.
- Reducing oral-to-genital spread — oral HSV-1 (the usual cause of cold sores) can be passed to a partner's genitals through oral sex, so the same caution about active cold sores applies.
None of these is a cure. There's no cure for herpes. It's a lifelong infection, and antivirals don't clear the latent virus or change how often it comes back once you stop the drug CDC STI guidelines. They suppress the virus while you take them, which is when transmission matters.
Why daily antivirals are the strongest tool
Most herpes transmission doesn't happen during a visible outbreak. It happens during asymptomatic shedding, when the virus is active on the skin with no sore to warn you. People with HSV-2 shed virus on roughly 10% of days even if they never get outbreaks, and most of that shedding is invisible JAMA. This is the single most misunderstood fact about herpes, and the reason "I don't have a sore, so I'm safe" is wrong.
Daily suppressive therapy works because it knocks down this silent shedding, not just the obvious flare-ups. A person with no current symptoms can still benefit a partner by taking a pill every day. If you're weighing whether suppression is right for your situation, the dosing and options live on our genital herpes treatment page, and your clinician will tailor it to you.
Condoms help — here's their limit
Condoms are worth using every time, but know what they can and can't do. Herpes lives on skin, and a condom only covers part of the genital area. Sores or shedding on the scrotum, the vulva, the inner thighs, or the buttocks fall outside what latex protects. Condoms reduce HSV-2 transmission meaningfully, but they can't bring it to zero the way they nearly do for fluid-borne infections like HIV.
Use condoms as one layer, not your whole plan. Paired with suppressive antivirals and avoiding contact during outbreaks, they add real protection. On their own, they leave a gap.
Does testing prevent transmission?
Testing matters most for confirming a diagnosis and guiding treatment, rather than as a routine screen for everyone. If you have a sore, swab the lesion and send it for type-specific NAAT or culture CDC. Without a sore, a type-specific blood test can help sort things out. You can read more about how this works on our herpes testing guide, and on what counts on a standard panel here: is herpes included in a standard std test?
Routine herpes screening of people without symptoms is not recommended. The CDC and USPSTF advise against general-population HSV-2 blood screening, mostly because the tests throw enough false positives to cause more harm than good in low-risk people. "Just get the herpes blood test to be safe" is usually not the right move, because it can label someone who isn't actually infected. If you do test after a possible exposure, timing matters; see when to test after exposure. To book a panel for the infections that are routinely screened, you can get tested online.
Is there a herpes vaccine or PrEP?
There's no approved herpes vaccine, and there's no PrEP (pre-exposure pill) or DoxyPEP regimen proven to prevent herpes the way those tools work for HIV or for bacterial STIs. The closest thing to chemoprevention for herpes is the partner with the infection taking daily suppressive antivirals, which works as protection delivered through the person who carries the virus rather than a pill the uninfected partner takes.
Not all herpes carries the same risk
The type of herpes you're dealing with changes the picture. Genital HSV-2 recurs and sheds far more often than genital HSV-1, so it's more transmissible over time. Genital HSV-1, increasingly common and largely from oral sex, tends to recur much less. In one US young-adult cohort, the share of new genital herpes caused by HSV-1 rose from 31% to 78%, and genital HSV-1 came back about once in the first year versus roughly four times a year for HSV-2 college cohort study.
| Factor | Genital HSV-1 | Genital HSV-2 |
|---|---|---|
| Typical source | Often oral sex from a cold-sore-type infection | Genital-to-genital contact |
| Recurrences | About once in the first year | About four times a year |
| Asymptomatic shedding | Less frequent | More frequent |
| Transmission risk over time | Lower | Higher |
Knowing your type from a type-specific test helps you and your partner gauge how aggressive prevention needs to be.
Putting it all together
No single method is perfect, but the layers stack. A realistic, strong plan for most serodiscordant couples: the partner with herpes takes daily suppressive antivirals, you both use condoms, you avoid all genital and oral contact at the first hint of an outbreak, and you talk openly so you're making decisions as a team.
On the emotional side: a diagnosis tends to land hard, but herpes is a manageable skin condition. Most people have few outbreaks as the years go on, and daily medication can make them rare while lowering the chance of passing it on. The most common mistake I see is assuming that no sore means no risk. That's why disclosure and, for many couples, daily suppression are worth it.
When to see a clinician
Reach out to a clinician if you have a new genital sore, if you're newly diagnosed and want to start suppressive therapy, or if outbreaks are frequent enough to disrupt your life or your relationship. Pregnancy warrants its own planning: antiviral medication late in pregnancy can reduce signs at delivery, suppressive acyclovir started around 36 weeks lowers the need for a cesarean, and a person with active lesions at the onset of labor should have a cesarean to protect the newborn from neonatal HSV (a serious infection in infants). If you're pregnant and have herpes, tell your prenatal provider early.