If you’ve been exposed to herpes, the most important step is to see a healthcare provider as soon as possible to discuss antiviral medication and get a testing plan in place. There’s no guaranteed way to prevent infection after exposure has already occurred, but understanding your actual risk, knowing what to watch for, and getting tested at the right time will put you in the best position to manage what comes next.
Your Actual Risk of Infection
A single exposure to herpes does not mean you will definitely become infected. The per-act transmission risk varies significantly depending on direction and whether a condom was used. For HSV-2 (the type most commonly associated with genital herpes), transmission from men to women occurs at a rate of about 28.5 per 1,000 unprotected sex acts, roughly a 3% chance per encounter. Transmission from women to men is considerably lower: about 1.7 per 1,000 unprotected acts, or less than 0.2% per encounter.
Condoms reduce the risk substantially. For women, condom use dropped the per-act rate from 28.5 to 1.3 per 1,000 acts. For men, the rate fell from 1.7 to 0.6 per 1,000 acts. Across multiple studies, consistent condom use lowered overall HSV-2 acquisition risk by about 30%. Risk also goes up if the infected partner was having an active outbreak at the time, since viral load is much higher during symptomatic episodes.
One thing worth knowing: washing your genitals, urinating, or douching after sex does not prevent herpes or any other STI. The virus enters through mucous membranes and microscopic breaks in the skin, and surface cleaning can’t reverse that contact.
Talk to a Provider About Antivirals
There is no formally approved post-exposure prophylaxis protocol for herpes the way there is for HIV. However, antiviral medications like valacyclovir are highly effective at suppressing the virus. In surgical settings where reactivation risk is high, valacyclovir has been shown to be 100% effective at preventing HSV outbreaks when started before or on the day of the procedure. Some providers will prescribe a short course of antivirals after a known sexual exposure, particularly if the exposure involved an active outbreak or broken skin.
The sooner you contact a provider, the better. If you’re going to take antivirals, starting them quickly gives you the best chance of suppressing viral replication before the virus establishes itself. Call your doctor, visit an urgent care clinic, or contact a sexual health clinic. Be specific about the type of exposure, when it happened, and whether the other person had visible sores.
What to Watch For in the Coming Weeks
The incubation period for herpes ranges from 1 to 26 days, though symptoms most commonly appear around 6 to 8 days after exposure. Not everyone who contracts herpes develops noticeable symptoms. Many first infections are mild enough to go unrecognized.
If you do develop a first outbreak, it typically starts with prodromal symptoms: tingling, itching, or shooting pain in the genitals, legs, hips, or buttocks. These sensations can appear hours or days before visible sores. The sores themselves usually begin as small red bumps that develop into fluid-filled blisters, then break open and crust over. A first outbreak can also come with flu-like symptoms including fever, body aches, and swollen lymph nodes in the groin. First episodes tend to be more severe than any recurrences that follow.
If you notice any of these symptoms, get to a provider while sores are still present. A PCR swab of an active lesion is the most accurate way to diagnose herpes and determine whether it’s HSV-1 or HSV-2. This distinction matters for understanding your long-term outlook, since HSV-1 genital infections recur far less frequently than HSV-2.
When and How to Get Tested
If no symptoms appear, you’ll need a blood test to find out whether you were infected. Blood tests detect antibodies your immune system produces in response to the virus, not the virus itself. The catch is timing: it can take up to 16 weeks or more after exposure for antibody levels to become reliably detectable on current tests. Testing too early often produces a false negative.
A reasonable approach is to get a baseline blood test within a few weeks of exposure (to confirm your status before the exposure) and then retest at around 12 to 16 weeks for a more definitive result. If you have a known negative baseline and then test positive at 16 weeks, you can be confident the infection came from the exposure in question. IgG blood tests can distinguish between HSV-1 and HSV-2, which is useful since many people already carry HSV-1 from childhood without knowing it.
Understanding Asymptomatic Shedding
One reason herpes spreads so easily is that the virus sheds from the skin even when no sores are visible. In the first year after infection, the virus is detectable on roughly 33.6% of all days, and about 26% of those days involve completely silent shedding with no symptoms at all. This rate declines over time: people who’ve had herpes for 1 to 9 years shed on about 20.6% of days, and those with infections lasting 10 years or more shed on about 16.7% of days.
This means the person you were exposed to may not have known they were contagious at the time. It also means that if you do acquire the infection, understanding shedding patterns becomes important for protecting future partners. Daily antiviral therapy significantly reduces both shedding frequency and transmission risk.
Protecting Partners While You Wait
During the window between exposure and a conclusive test result, the safest approach is to use condoms consistently and avoid sexual contact entirely if any symptoms appear. If you develop sores, you are highly contagious until they’ve fully healed. Even without symptoms, condoms offer meaningful protection: consistent use reduces HSV-2 transmission risk by about 30%, and every increase in the frequency of condom use lowers risk further, roughly 7% for every additional quarter of the time they’re used.
Being honest with sexual partners about a possible exposure is difficult but important. Many people carry herpes without knowing it, since the CDC estimates that most infections are never formally diagnosed. A known exposure that you’re actively monitoring is, in many ways, a more informed position than most people are in.