Chance of spreading herpes with no outbreak

Herpes viruses are most likely to be transmitted during an outbreak, so it's better to not have sex during this time. Herpes can also be passed on to others in symptom-free phases, though. This risk can be reduced considerably by using condoms.

If you have genital herpes, there are some things you can do on your own to protect your partner from infection. The main things are

• not having sex during an outbreak,

• using condoms during symptom-free phases, and

• talking openly with your partner about the disease.

Preventive treatment with antiviral medication may be an option for people who have genital herpes very frequently. This medication inhibits the activity of the virus, thereby lowering the risk of infecting partners.

How big is the risk of infection?

The likelihood of being infected with genital herpes during sex depends on many factors, including how often you have sex, whether and how frequently you use condoms, and how long your partner has already been infected. Someone who has had the virus for a long time is less contagious than someone who has just been infected. In general, women have a higher risk of becoming infected than men. Having other sexually transmitted diseases such as HIV also increases the risk of transmission.

In studies with couples where one partner had genital herpes, the other partner became infected within one year in 5 to 10% of the couples. The people in these studies only rarely used condoms, though – and if they did, it was mostly during an outbreak. One of these studies showed that infection occurred in an estimated 1 out of 1,000 sexual acts.

Should you get tested?

It’s a good idea for the partners of people with genital herpes to have a blood test for herpes antibodies. This can help them to decide whether to use antiviral medication as protection, for example. Both partners may already have the same virus type. Then there’s no reason to take medication to protect each other.

If one of the partners has HSV-1 or cold sores and the other one has HSV-2 or genital herpes, they could infect one another with the other virus. If one partner has herpes viruses in their body and the other doesn’t, condoms are one way to prevent infection.

How effective is medication at preventing infection?

If you have genital herpes, you will probably be somewhat less likely to infect your partner if you use antiviral medication for prevention. The medications used for this purpose include aciclovir, famciclovir and valaciclovir. They must be taken every day over a long period of time, though. One study showed that over a period of eight months,

• 4 out of 100 people became infected when the partner with the virus took a placebo, and

• 2 out of 100 people became infected when the partner with the virus took antiviral medication every day.

These couples were also advised to use condoms as well – but many didn't use them consistently. So it’s not clear whether taking antiviral medication can lower the risk of infection even further if you always use condoms anyway, or whether using condoms is just as effective on its own.

Whether or not you would like to use preventive medication is ultimately an individual decision. Many factors can play a role, such as how long you or your partner have had the infection, how frequent and severe the outbreaks are, whether you are male or female, the frequency of sexual contact and whether you use condoms.

Sources

• IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

  Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. We do not offer individual consultations.

  Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

What is genital herpes?

Genital herpes is a sexually transmitted disease (STD) caused by the herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2).

How common is genital herpes?

Genital herpes infection is common in the United States. CDC estimated that there were 572,000 new genital herpes infections in the United States in a single year.1 Nationwide, 11.9 % of persons aged 14 to 49 years have HSV-2 infection (12.1% when adjusted for age).2 However, the prevalence of genital herpes infection is higher than that because an increasing number of genital herpes infections are caused by HSV-1. 3 Oral HSV-1 infection is typically acquired in childhood; because the prevalence of oral HSV-1 infection has declined in recent decades, people may have become more susceptible to contracting a genital herpes infection from HSV-1. 4

HSV-2 infection is more common among women than among men; the percentages of those infected during 2015-2016 were 15.9% versus 8.2% respectively, among 14 to 49 year olds. 2 This is possibly because genital infection is more easily transmitted from men to women than from women to men during penile-vaginal sex. 5 HSV-2 infection is more common among non-Hispanic blacks (34.6%) than among non-Hispanic whites (8.1%). 2 A previous analysis found that these disparities, exist even among persons with similar numbers of lifetime sexual partners. Most infected persons may be unaware of their infection; in the United States, an estimated 87.4% of 14 to 49 year olds infected with HSV-2 have never received a clinical diagnosis. 6

The age-adjusted percentage of persons in the United States infected with HSV-2 decreased from 18.0% in 1999–2000 to 12.1% in 2015-2016. 2

How do people get genital herpes?

Infections are transmitted through contact with HSV in herpes lesions, mucosal surfaces, genital secretions, or oral secretions. 5 HSV-1 and HSV-2 can be shed from normal-appearing oral or genital mucosa or skin. 7,8 Generally, a person can only get HSV-2 infection during genital contact with someone who has a genital HSV-2 infection. However, receiving oral sex from a person with an oral HSV-1 infection can  result in getting a genital HSV-1 infection. 4  Transmission commonly occurs from contact with an infected partner who does not have visible lesions and who may not know that he or she is infected. 7 In persons with asymptomatic HSV-2 infections, genital HSV shedding occurs on 10.2% of days, compared to 20.1% of days among those with symptomatic infections. 8

What are the symptoms of genital herpes?

Most individuals infected with HSV are asymptomatic or have very mild symptoms that go unnoticed or are mistaken for another skin condition. 9 When symptoms do occur, herpes lesions typically appear as one or more vesicles, or small blisters, on or around the genitals, rectum or mouth. The average incubation period for an initial herpes infection is 4 days (range, 2 to 12) after exposure. 10 The vesicles break and leave painful ulcers that may take two to four weeks to heal after the initial herpes infection. 5,10 Experiencing these symptoms is referred to as having a first herpes “outbreak” or episode.

Clinical manifestations of genital herpes differ between the first and recurrent (i.e., subsequent) outbreaks. The first outbreak of herpes is often associated with a longer duration of herpetic lesions, increased viral shedding (making HSV transmission more likely) and systemic symptoms including fever, body aches, swollen lymph nodes, or headache. 5,10 Recurrent outbreaks of genital herpes are common, and many patients who recognize recurrences have prodromal symptoms, either localized genital pain, or tingling or shooting pains in the legs, hips or buttocks, which occur hours to days before the eruption of herpetic lesions. 5 Symptoms of recurrent outbreaks are typically shorter in duration and less severe than the first outbreak of genital herpes. 5 Long-term studies have indicated that the number of symptomatic recurrent outbreaks may decrease over time. 5 Recurrences and subclinical shedding are much less frequent for genital HSV-1 infection than for genital HSV-2 infection.5

What are the complications of genital herpes?

Genital herpes may cause painful genital ulcers that can be severe and persistent in persons with suppressed immune systems, such as HIV-infected persons. 5 Both HSV-1 and HSV-2 can also cause rare but serious complications such as aseptic meningitis (inflammation of the linings of the brain). 5 Development of extragenital lesions (e.g. buttocks, groin, thigh, finger, or eye) may occur during the course of infection. 5

Some persons who contract genital herpes have concerns about how it will impact their overall health, sex life, and relationships. 5,11 There can also be considerable embarrassment, shame, and stigma associated with a herpes diagnosis that can substantially interfere with a patient’s relationships. 10 Clinicians can address these concerns by encouraging patients to recognize that while herpes is not curable, it is a manageable condition. 5 Three important steps that providers can take for their newly-diagnosed patients are: giving information, providing support resources, and helping define treatment and prevention options. 12 Patients can be counseled that risk of genital herpes transmission can be reduced, but not eliminated, by disclosure of infection to sexual partners, 5 avoiding sex during a recurrent outbreak, 5 use of suppressive antiviral therapy, 5,10 and consistent condom use. 7 Since a diagnosis of genital herpes may affect perceptions about existing or future sexual relationships, it is important for patients to understand how to talk to sexual partners about STDs. One resource can be found here: www.gytnow.org/talking-to-your-partner

There are also potential complications for a pregnant woman and her newborn child. See “How does herpes infection affect a pregnant woman and her baby?” below for information about this.

What is the link between genital herpes and HIV?

Genital ulcerative disease caused by herpes makes it easier to transmit and acquire HIV infection sexually. There is an estimated 2- to 4-fold increased risk of acquiring HIV, if individuals with genital herpes infection are genitally exposed to HIV. 13-15 Ulcers or breaks in the skin or mucous membranes (lining of the mouth, vagina, and rectum) from a herpes infection may compromise the protection normally provided by the skin and mucous membranes against infections, including HIV. 14 In addition, having genital herpes increases the number of CD4 cells (the target cell for HIV entry) in the genital mucosa. In persons with both HIV and genital herpes, local activation of HIV replication at the site of genital herpes infection can increase the risk that HIV will be transmitted during contact with the mouth, vagina, or rectum of an HIV-uninfected sex partner. 14

How does genital herpes affect a pregnant woman and her baby?

Neonatal herpes is one of the most serious complications of genital herpes.5,16 Healthcare providers should ask all pregnant women if they have a history of genital herpes.11 Herpes infection can be passed from mother to child during pregnancy or childbirth, or babies may be infected shortly after birth, resulting in a potentially fatal neonatal herpes infection. 17 Infants born to women who acquire genital herpes close to the time of delivery and are shedding virus at delivery are at a much higher risk for developing neonatal herpes, compared with women who have recurrent genital herpes . 16,18-20 Thus, it is important that women avoid contracting herpes during pregnancy. Women should be counseled to abstain from intercourse during the third trimester with partners known to have or suspected of having genital herpes. 5,11

While women with genital herpes may be offered antiviral medication late in pregnancy through delivery to reduce the risk of a recurrent herpes outbreak, third trimester antiviral prophylaxis has not been shown to decrease the risk of herpes transmission to the neonate.11,21,22 Routine serologic HSV screening of pregnant women is not recommended. 11 However, at onset of labor, all women should undergo careful examination and questioning to evaluate for presence of prodromal symptoms or herpetic lesions. 11 If herpes symptoms are present a cesarean delivery is recommended to prevent HSV transmission to the infant.5,11,23 There are detailed guidelines for how to manage asymptomatic infants born to women with active genital herpes lesions.24

How is genital herpes diagnosed?

HSV nucleic acid amplification tests (NAAT) are the most sensitive and highly specific tests available for diagnosing herpes. However, in some settings viral culture is the only test available. The sensitivity of viral culture can be low, especially among people who have recurrent or healing lesions. Because viral shedding is intermittent, it is possible for someone to have a genital herpes infection even though it was not detected by NAAT or culture. 11

Type-specific virologic tests can be used for diagnosing genital herpes when a person has recurrent symptoms or lesion without a confirmatory NAAT, culture result, or has a partner with genital herpes. Both virologic tests and type-specific serologic tests should be available in clinical settings serving patients with, or at risk for, sexually transmitted infections. 11

Given performance limitations with commercially available type-specific serologic tests (especially with low index value results [<3]), a confirmatory test (Biokit or Western Blot) with a second method should be performed before test interpretation. If confirmatory tests are unavailable, patients should be counseled about the limitations of available testing before serologic testing. Healthcare providers should also be aware that false-positive results occur. In instances of suspected recent acquisition, serologic testing within 12 weeks after acquisition may be associated with false negative test results. 11

HSV-1 serologic testing does not distinguish between oral and genital infection, and typically should not be performed for diagnosing genital HSV-1 infection. Diagnosis of genital HSV-1 infection is confirmed by virologic tests from lesions. 11

CDC does not recommend screening for HSV-1 or HSV-2 in the general population due to limitations of the type specific serologic testing. 11 Several scenarios where type-specific serologic HSV tests may be useful include:

• Patients with recurrent genital symptoms or atypical symptoms and negative HSV NAAT or culture;
• Patients with a clinical diagnosis of genital herpes but no laboratory confirmation; and
• Patients who report having a partner with genital herpes. 11

Patients who are at higher risk of infection (e.g., presenting for an STI evaluation, especially those with multiple sex partners), and people with HIV might need to be assessed for a history of genital herpes symptoms, followed by serology testing in those with genital symptoms. 11

Providers are strongly encouraged to look at CDC’s STI Treatment Guidelines for further diagnostic considerations.

Is there a cure or treatment for herpes?

There is no cure for herpes. Antiviral medications can, however, prevent or shorten outbreaks during the period of time the person takes the medication.11 In addition, daily suppressive therapy (i.e., daily use of antiviral medication) for herpes can reduce the likelihood of transmission to partners.11

There is currently no commercially available vaccine that is protective against genital herpes infection. Candidate vaccines are in clinical trials.

How can herpes be prevented?

Correct and consistent use of latex condoms can reduce, but not eliminate, the risk of transmitting or acquiring genital herpes because herpes virus shedding can occur in areas that are not covered by a condom.25,26

The surest way to avoid transmission of STDs, including genital herpes, is to abstain from sexual contact, or to be in a long-term mutually monogamous relationship with a partner who has been tested for STDs and is known to be uninfected.

Persons with herpes should abstain from sexual activity with partners when herpes lesions or other symptoms of herpes are present. It is important to know that even if a person does not have any symptoms, he or she can still infect sex partners. Sex partners of infected persons should be advised that they may become infected and they should use condoms to reduce the risk. Sex partners can seek testing to determine if they are infected with HSV.

Daily treatment with valacyclovir decreases the rate of HSV-2 transmission in discordant, heterosexual couples in which the source partner has a history of genital HSV-2 infection. 27 Such couples should be encouraged to consider suppressive antiviral therapy as part of a strategy to prevent transmission, in addition to consistent condom use and avoidance of sexual activity during recurrences.

Counseling those with genital herpes, as well as their sex partners, is critical. It can help patients cope with the infection and prevent further spread into the community. The STI Treatment Guidelines includes messaging broken down by herpes type. 11

Sources:

1.  Kreisel KM, Spicknall IH, Gargano JW, Lewis FM, Lewis RM, Markowitz LE, Roberts H, Satcher Johnson A, Song R, St. Cyr SB, Weston EJ, Torrone EA, Weinstock HS. Sexually transmitted infections among US women and men: Prevalence and incidence estimates, 2018. Sex Transm Dis 2021; in press.

2. McQuillan G, Kruszon-Moran D, Flagg EW, Paulose-Ram R. Prevalence of herpes simplex virus type 1 and type 2 in persons aged 14–49: United States, 2015–2016. NCHS Data Brief, no 304. Hyattsville, MD: National Center for Health Statistics. 2018

3. Xu F, Sternberg MR, Kottiri BJ, et al. Trends in herpes simplex virus type 1 and type 2 seroprevalence in the United States. JAMA, 2006. 296(8): 964–73.

4. Bradley H, Markowitz L, Gibson T, et al. Seroprevalence of herpes simplex virus types 1 and 2—United States, 1999–2010. J Infect Dis, 2014. 209(3):325-33.

5. Corey L, Wald A. Genital Herpes. In: Holmes KK, Sparling PF, Stamm WE, et al. (editors). Sexually Transmitted Diseases. 4th ed. New York: McGraw-Hill; 2008: 399–437.

6. Fanfair RN, Zaidi A, Taylor LD, Xu F, Gottlieb S, Markowitz L. Trends in seroprevalence of herpes simplex virus type 2 among non-Hispanic blacks and non-Hispanic whites aged 14 to 49 years–United States, 1988 to 2010. Sex Transm Dis, 2013. 40(11):860-4.

7. Mertz GJ. Asymptomatic shedding of herpes simplex virus 1 and 2: implications for prevention of transmission. J Infect Dis, 2008. 198(8): 1098–1100.

8. Tronstein E, Johnston C, Huang M, et al. Genital shedding of herpes simplex virus among symptomatic and asymptomatic persons with HSV-2 infection. JAMA, 2011. 305(14): 1441–9.

9. Wald A, Zeh J, Selke S, et al. Reactivation of genital herpes simplex virus type 2 infection in asymptomatic seropositive persons. New Engl J Med, 2000. 342(12): 844–50.

10. Kimberlin DW, Rouse DJ. Genital Herpes. N Engl J Med, 2004. 350(19): 1970–7.

11. Workowski, KA, Bachmann, LH, Chang, PA, et. al. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep 2021; 70(No. 4): 1-187.

12. Alexander L, Naisbett B. Patient and physician partnerships in managing genital herpes. J Infect Dis, 2002. 186(Suppl 1): S57–S65.

13. Freeman EE, Weiss HA, Glynn JR, Cross PL, Whitworth JA, Hayes RJ. Herpes simplex virus 2 infection increases HIV acquisition in men and women: systematic review and meta-analysis of longitudinal studies. AIDS, 2006. 20(1): 73–83.

14. Barnabas RV, Celum C. Infectious co-factors in HIV-1 transmission. Herpes simplex virus type-2 and HIV-1: new insights and interventions. Curr HIV Res, 2012. 10(3): 228–37

15. Corey L, Wald A, Celum CL, Quinn TC. The effects of herpes simplex virus-2 on HIV-1 acquisition and transmission: a review of two overlapping epidemics. JAIDS, 2004. 35(5): 435–45.

16. Brown ZA, Selke S, Zeh J, et al. The acquisition of herpes simplex virus during pregnancy. N Engl J Med, 1997. 337(8): 509–15.

17. Kimberlin DW. Herpes simplex virus infections in the newborn. Semin Perinatol, 2007. 31(2): 19–25.

18. Brown ZA, Wald A, Morrow RA, Selke S, Zeh J, Corey L. Effect of serologic status and cesarean delivery on transmission rates of herpes simplex virus from mother to infant. JAMA, 2003. 289(2):203–9

19. Brown ZA, Benedetti J, Ashley R, et al. Neonatal herpes simplex virus infection in relation to asymptomatic maternal infection at the time of labor. N Engl J Med, 1991. 324(18):1247–52

20. Brown ZA, Vontver LA, Benedetti J, et al. Effects on infants of a first episode of genital herpes during pregnancy. N Engl J Med, 1987. 317(20):1246–51

21. Hollier LM, Wendel GD. Third trimester antiviral prophylaxis for preventing maternal genital herpes simplex virus (HSV) recurrences and neonatal infection. Cochrane Database Syst Rev, 2008. Issue 1: Art. No. CD004946.

22. Pinninti SG, Angara R, Feja KN, et al. Neonatal herpes disease following maternal antenatal antiviral suppressive therapy: a multicenter case series. J Pediatr, 2012. 161(1):134-8.

23. American College of Obstetricians and Gynecologists (ACOG). ACOG Practice Bulletin. Clinical management guidelines for obstetrician-gynecologists. No. 82 June 2007. Management of herpes in pregnancy. Obstet Gynecol, 2007. 109(6): 1489–98.

24. Kimberlin DW, Balely J, Committee on Infectious Diseases, Committee on Fetus and Newborn.  Guidance on management of asymptomatic neonates born to women with active genital herpes lesions. Pediatrics, 2013. 131(2):e635-46.

25. Martin ET, Krantz A, Gottlieb SL, et al. A pooled analysis of the effect of condoms in preventing HSV-2 acquisition. Arch Intern Med, 2009. 169(13): 1233–40.

26. Wald A, Langenberg AGM, Link K, et al. Effect of condoms on reducing the transmission of herpes simplex virus type 2 from men to women. JAMA, 2001. 285(24): 3100–6.

27. Corey L, Wald A, Patel R, et al. Once-daily valacyclovir to reduce the risk of transmission of genital herpes. N Engl J Med, 2004. 350:11–20.

Is it possible for herpes to not spread?

Is herpes contagious all the time?

Can you be exposed to herpes outbreak and not get it?

Is herpes less contagious over time?