Sexually Transmitted Diseases (STDs)

Genital Herpes Screening

Frequently Asked Questions

Since so many people have HSV infection but don’t know they have it, why doesn’t CDC recommend routine testing all sexually active people for genital herpes?

Herpes blood tests (also called HSV-2 type-specific serologic tests) can be very useful for diagnosing type 2 genital herpes infection in certain situations; 1) when someone has genital symptoms that might be related to herpes, and 2) when someone has a sex partner with symptomatic genital herpes. Herpes blood testing may also be useful for people seeking a full STD evaluation, especially for persons with multiple sex partners. However, CDC does not currently recommend routine type 2 HSV testing in someone with no symptoms suggestive of herpes infection (i.e., for the general population). We need additional evaluation to understand the benefits of testing, including whether routine HSV-2 testing improves health and reduces spread of infection in the population. In addition, these tests can be expensive; false positive test results may occur in some persons with a low likelihood of infection; and the diagnosis may have adverse psychological effects for some people. Although there is not enough evidence to recommend widespread testing, individual persons who are at risk for HSV-2 infection, such as those with a partner known to have a history of symptomatic herpes infection, or those with multiple partners, should consult their healthcare providers to discuss type 2 HSV serologic testing.  Also, those concerned about genital herpes infection should discuss their concerns with their health care provider. 

Is a blood test for genital herpes usually included when I ask to be tested for "everything" (all STDs)? Why does CDC recommend testing for other STDs but not herpes?

Herpes type 2 blood testing may or may not be included in a full STD evaluation, as STD testing depends on a number of factors, such as behavioral risk factors (e.g. number of partners, consistent condom use, etc.) and how common the infection is in the community. When getting an evaluation, it is important to ask your provider which infections are being tested for, which infections are not being tested for, and why. STD screening tests are usually done for infections that can have serious outcomes if they are left untreated. For example, finding and treating curable STDs like chlamydia can prevent those infections from leading to serious complications, such as infertility (the inability to get pregnant) in women. Genital herpes infections can cause intermittent symptoms that may be uncomfortable, but infection does not usually result in serious complications in healthy adults. Although the symptoms of genital herpes can be treated with medication, there is currently no cure for herpes infections. HSV blood testing may be useful for people seeking an STD evaluation, but CDC does not currently recommend routine HSV testing in someone with no symptoms suggestive of herpes infection. People who are specifically concerned about genital herpes should discuss with their healthcare providers whether they would benefit from testing.

Wouldn’t testing everyone for HSV limit the spread of genital herpes?

For STDs that can be cured with antibiotics, including syphilis, gonorrhea, and chlamydia, an important public health prevention strategy is to quickly identify and treat infected persons.  When these infected people are treated and cured, future spread of the infection is prevented. However, genital herpes causes an incurable, chronic lifelong infection. It is not clear that the identification of persons with HSV infection would decrease the spread of HSV in the population. There is no evidence that detection of HSV infection through testing of persons with no symptoms suggestive of herpes leads to a change their sexual behavior. Because the tests can be expensive and the diagnosis may have adverse psychological or effects for some people, widespread testing for HSV is not currently recommended.

Why is testing for genital herpes only recommended for people who have symptoms?

Testing for genital herpes can be useful when someone has genital symptoms that might be related to herpes. Testing helps by confirming the diagnosis and allowing the provider to counsel about what to expect in the future, the role of treatment, and what preventive measures should be taken to reduce transmission to current and future partners.  Testing can also be useful when someone has a sex partner with history of genital herpes to see if they are infected. If uninfected, then counseling about ways to reduce risk of acquiring genital herpes infected should be offered.  Herpes blood testing may be useful for people seeking a full STD evaluation, especially for people with multiple sex partners. Testing is recommended for people with symptoms, because treatment is available to partially control the symptoms of herpes. In addition, persons with symptomatic genital herpes who take daily antiviral medication can reduce the risk of spreading HSV-2 to their sex partners by 50%.

Are people with genital herpes at increased risk of contracting HIV infection?

Many studies have shown that HSV-2 infection increases the risk of contracting HIV infection by at least two-fold, even when there are no symptoms of genital herpes. HSV-2 infection can cause tiny breaks in the genital and anal area that can provide HIV an entry into the body. In addition, herpes infection attracts the type of cells that HIV infects (“target cells”) to the genital area. This increases the chance of getting HIV if exposed to it.

Can testing and treating genital herpes decrease the risk for HIV infection?

Two large, well-done studies (randomized controlled trials) found that, for people with HSV-2 infection, taking daily treatment to suppress herpes infection did not lower the chances of getting HIV infection. So, unfortunately, testing for genital herpes and treating with herpes medications will not diminish the  potential risk of HIV acquisition due to HSV-2 infection.

Why are there state-by-state data for common STDs but not for genital herpes?

Infections with HSV-1 and HSV-2 are not among the "notifiable" diseases in the United States, while syphilis, gonorrhea and chlamydia are. Healthcare providers in all 50 states are required by law to report the diagnosis of syphilis, gonorrhea and chlamydia to their state or local health departments and eventually to CDC. CDC then routinely publishes state-by-state data for these infections. Because HSV infections are not legally mandated notifiable infections, state-by-state data typically are not feasible. Public health surveillance for HSV infections is mainly done through population-based, national surveys. 
The Council of State and Territorial Epidemiologists (CSTE), in collaboration with CDC, determines whether a disease should be nationally notifiable.  To make this decision, they follow a number of public health principles, including but not limited to: (1) whether an intervention is available and a public health response is indicated; (2) a sufficient, timely source of the required information does not already exist; and (3) the disease or condition represents a significant threat, defined by multiple parameters.  In the case of HSV type 2, there are data gathered in the National Health and Nutrition Examination Survey (NHANES); thus, the required information already exists.

Why have false positive tests been used as an argument against routine testing for genital herpes but not for other STDs, which can also have false positives?  

False positive tests can occur with many diagnostic tests, including STD tests, and the chance of a false positive test result increases as the likelihood of the infection decreases in the person being tested. False positive HSV type 2 results can occur, especially in persons with a low likelihood of HSV infection. It is not clear whether knowledge of a herpes diagnosis improves the health of people taking the tests and reduces spread of HSV in the population. Thus, the harm of possible false positive tests may be a greater consideration. Unlike curable STDs like chlamydia, herpes infections are life-long and cannot be cured with a single course of antibiotics, so it is especially important to avoid false positive tests.

Should we be testing for HSV to prevent other diseases? For example, is Alzheimer’s disease related to HSV-1 infection?

Alzheimer's disease is a progressive brain disease that develops because of a complex series of events that occur in the brain over a long period of time. The causes of Alzheimer’s disease may include genetic, environmental, or other factors. Several different factors have been statistically linked to Alzheimer’s disease, including HSV-1 infection in some studies. However, some investigations suggest that viruses other than HSV-1 may influence Alzheimer's disease.  More research is needed to confirm or refute the link between HSV-1 infection and Alzheimer’s disease.