Serologic Screening for Genital Herpes Infection
Genital herpes is a prevalent sexually transmitted infection (STI) in the United States. Centers for Disease Control and Prevention (CDC) estimates that almost 1 in 6 persons aged 14 to 49 years have genital herpes. Genital herpes infection is caused by 2 subtypes of HSV, HSV-1 and HSV-2. In the past, most cases of genital herpes in the United States have been caused by infection with HSV-2. Recent data suggests that the rates of genital herpes due to HSV-1 infection may be increasing.
In adolescents and adults, genital infection often results in outbreaks of vesicles in the area in and around the genitals and rectum. These vesicles break, leaving painful ulcers. The first outbreak of genital herpes is usually the most painful and may be accompanied by flu-like symptoms, including fever, body aches, and swollen lymph nodes. Among persons who have a symptomatic first outbreak, 70% to 90% will have at least 1 more symptomatic outbreak within the first year, with an average of 4 outbreaks per year. Although the risk of transmission is higher during a symptomatic outbreak, persons with genital herpes can spread the infection to sexual partners even when they are asymptomatic.
The United States Preventive Services Task Force (USPSTF) does not recommend serologic screening for genital HSV infection in asymptomatic persons. The most widely used, currently available serologic screening test for HSV-2 is not suitable for population-based screening, based on its low specificity, lack of widely available confirmatory testing, and its high false-positive rate. HerpeSelect (Focus Diagnostics) has a pooled estimate of sensitivity of 99% (95% CI, 97 to 100) and a pooled estimate of specificity of 83% (95% CI, 72 to 91). A second test, Biokit HSV-2 Rapid Test (Biokit USA), has a pooled estimate of sensitivity of 84% (95% CI, 73 to 91) and specificity of 95% (95% CI, 93 to 97). In the general US population, the positive predictive value of may be as low as 75% for the Biokit test and as low as 50% for HerpeSelect. Serologic screening in asymptomatic persons results in a large number of false-positive results.
While HSV-1 infection can be identified by serologic tests, the tests cannot determine if the site of infection is oral or genital. These serologic tests are not useful for screening for asymptomatic genital herpes resulting from HSV-1 infection.
Western blot is considered to be the gold standard for the serologic diagnosis of herpes. Western blot test results can be obtained by sending a blood sample to a single research laboratory (University of Washington Clinical Virology Laboratory); however, it is not widely available as a screening or confirmatory test for persons who screen positive for HSV-2 on one of the less-specific, commercially available serologic tests.
References
Serologic Screening for Genital Herpes Infeciton: US Preventive Services Task Force Recommendation Statement. JAMA 2016;316(23)2525-2530.
