Genital Herpes - CDC Fact Sheet
What is genital herpes?
Genital herpes is a sexually transmitted disease (STD) caused by the herpes simplex viruses type 1 (HSV-1) or type 2 (HSV-2).
How common is genital herpes?
CDC estimates that, annually, 776,000 people in the United States get new herpes infections. Genital herpes infection is common in the United States. Nationwide, 16.2% of persons aged 14 to 49 years have HSV-2 infection.  The overall prevalence of genital herpes is likely higher than 16.2%, because an increasing number of genital herpes infections are caused by HSV-1. Increases in genital HSV-1 infections have been found in patient populations worldwide. 
HSV-2 infection is more common among women than among men (20.9% versus 11.5% in 14 to 49 year olds). Infection is more easily transmitted from men to women than from women to men. HSV-2 infection is more common among non-Hispanic blacks (39.2%) than among non-Hispanic whites (12.3%) or Mexican Americans (10.1%). This disparity remains even among persons with similar numbers of lifetime sexual partners. For example, among persons with 2–4 lifetime sexual partners, HSV-2 is still more prevalent among non-Hispanic blacks (34.3%) than among non-Hispanic whites (9.1%) or Mexican Americans (13%). Most infected persons are unaware of their infection. In the United States, an estimated 81.1% of 14–49 year olds infected with HSV-2 have never received a clinical diagnosis. 
The percentage of persons in the United States who are infected with HSV-2 decreased from 21.0% in 1988–1994 to 17.0% in 1999–2004. However, HSV-2 prevalence has changed very little since 2004. 
How do people get genital herpes?
Infections are transmitted through contact with lesions, mucosal surfaces, genital secretions, or oral secretions. HSV-1 and HSV-2 can also be shed from skin that looks normal. In persons with asymptomatic HSV-2 infections, genital HSV shedding occurs on 10% of days, and on most of those days the person has no signs or symptoms.  Generally, a person can only get HSV-2 infection during sexual contact with someone who has a genital HSV-2 infection. Transmission most commonly occurs from an infected partner who does not have a visible sore and may not know that he or she is infected. 
What are the symptoms of genital herpes?
Most individuals infected with HSV-1 or HSV-2 are asymptomatic, or have very mild symptoms that go unnoticed or are mistaken for another skin condition. As a result, 81.1% of infected individuals remain unaware of their infection. [1, 6] When symptoms do occur, they typically appear as one or more vesicles on or around the genitals, rectum or mouth. The average incubation period after exposure is 4 days (range, 2 to 12).  The vesicles break and leave painful ulcers that may take two to four weeks to heal. Experiencing these symptoms is referred to as having an "outbreak," or episode.
Clinical manifestations of genital herpes differ between the first and recurrent outbreaks of HSV. 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, and headache.  Recurrent outbreaks of genital herpes are common, in particular during the first year of infection. Approximately half of patients who recognize recurrences have prodromal symptoms, such as mild tingling or shooting pains in the legs, hips and buttocks occurring hours to days before eruption of herpetic lesions. Symptoms of recurrent outbreaks are typically shorter in duration and less severe than the first outbreak of genital herpes. Although the infection can stay in the body indefinitely, the number of outbreaks tends to decrease over time. Recurrences are much less frequent for genital HSV-1 infection than for genital HSV-2 infection. 
What are the complications of genital herpes?
Genital herpes causes painful genital ulcers in many adults that can be severe and persistent in persons with suppressed immune systems, such as HIV-infected persons. Both HSV-1 and HSV-2 can also cause rare but serious complications such as blindness, encephalitis (inflammation of the brain), and aseptic meningitis (inflammation of the linings of the brain). Development of extragenital lesions in the buttocks, groin, thigh, finger, and eye may occur during the course of infection. 
Some persons who contract genital herpes have concerns about how it will impact their overall health, sex life, and relationships. There can be can be considerable embarrassment, shame, and stigma associated with a herpes diagnosis and this can substantially interfere with a patient’s relationships.  Clinicians can address these concerns by encouraging patients to recognize that while herpes is not curable, it is a manageable condition. Three important steps that providers can take for their newly-diagnosed patients are: giving information, providing support resources, and helping define options.  Since a genital herpes diagnosis 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 unborn 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 make it easier to transmit and acquire HIV infection sexually. There is an estimated 2- to 4-fold increased risk of acquiring HIV, if exposed to that infection when genital herpes is present. [11-13] This is because genital herpes can cause ulcers or breaks in the skin or mucous membranes (lining of the mouth, vagina, and rectum), which provide protection against infections, including HIV. Herpetic genital ulcers can bleed easily, and when they come into contact with the mouth, vagina, or rectum during sex, they increase the risk of HIV transmission.
How does genital herpes affect a pregnant woman and her baby?
Healthcare providers should ask all pregnant women if they have a history of genital herpes. Herpes infection can be passed from mother to child resulting in a potentially fatal infection (neonatal herpes), one of the most serious complications of genital herpes. During pregnancy there is a higher risk of perinatal transmission during the first outbreak than with a recurrent outbreak, 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 or suspected of having genital herpes. 
A woman with genital herpes may be offered antiviral medication from 36 weeks gestation through delivery to reduce the risk of a recurrent outbreak.  Routine HSV screening of pregnant women is not recommended. However, at onset of labor, all women should undergo careful examination and questioning to evaluate for presence of prodromal symptoms or herpetic lesions. If herpes symptoms are present a cesarean delivery is recommended to prevent HSV transmission to the infant. [16, 9]
How is genital herpes diagnosed?
Numerous herpes diagnostic tests are available. Direct (or virologic) tests detect viable virus, viral antigen, or viral nucleic acid. Viral culture is currently the reference standard for diagnosing genital herpes. HSV culture requires collection of a sample from the sore and, once viral growth is seen, specific cell staining to differentiate between HSV-1 and HSV-2. Nucleic acid amplification techniques (NAATs), such as PCR, test for viral DNA or RNA and allow for more rapid and accurate results.  Indirect (or serologic) tests are blood tests that detect antibodies to the herpes virus. Several ELISA-based serologic tests are FDA approved and available commercially. Older assays that do not accurately distinguish HSV-1 from HSV-2 antibody remain on the market, so providers should specifically request serologic type-specific assays when blood tests are performed for their patients. HSV-1 ELISA results are considered to be reliable because HSV-1 is ubiquitous in most populations. However, false positive HSV-2 ELISA results are more often seen when testing is done in populations with a lower prevalence of HSV-2. 
For the symptomatic patient, testing with both direct and indirect assays can determine whether it is a new infection or a newly-recognized old infection. A primary infection would be supported by a positive virologic test and a negative serologic test, while the diagnosis of recurrent disease would be supported by positive virologic and serologic test results. 
CDC does not recommend screening for HSV-1 or HSV-2 in the general population. Several scenarios where type-specific HSV tests may be useful include
- Patients with recurrent genital symptoms or atypical symptoms and negative HSV cultures;
- Patients with a clinical diagnosis of genital herpes but no laboratory confirmation;
- Patients who report having a partner with genital herpes;
- Patients presenting for an STD evaluation (especially those with multiple partners);
- Persons with HIV infection; and
- MSM at increased risk for HIV acquisition. 
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. In addition, daily suppressive therapy (i.e. daily use of antiviral medication) for herpes can reduce the likelihood of transmission to partners.
Several clinical trials have tested vaccines against genital herpes infection, but there is currently no commercially available vaccine that is protective against genital herpes infection. One vaccine trial showed efficacy among women whose partners were HSV-2 infected, but only among women who were not infected with HSV-1. No efficacy was observed among men whose partners were HSV-2 infected. A subsequent trial testing the same vaccine showed some protection from genital HSV-1 infection, but no protection from HSV-2 infection. 
How can herpes be prevented?
Correct and consistent use of latex condoms can reduce the risk of genital herpes. [21–22] However, outbreaks can occur in areas that are not covered by a condom.
The surest way to avoid transmission of sexually transmitted diseases, 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 and is known to be uninfected.
Persons with herpes should abstain from sexual activity with partners when sores 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.
Where can I get more information?
Division of STD Prevention (DSTDP)
Centers for Disease Control and Prevention
Personal health inquiries and information about STDs:
CDC-INFO Contact Center
American Sexual Health
P. O. Box 13827
Research Triangle Park, NC 27709-3827
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