Genital herpes is a common sexually transmitted infection (STI) caused by the herpes simplex virus (HSV), which has two main types: HSV-1 and HSV-2. Despite its prevalence, HSV is noticeably absent from routine STI screening panels that include tests for chlamydia, gonorrhea, and HIV. This omission often confuses patients seeking comprehensive sexual health testing. The decision not to include HSV in standard screening is rooted in limitations of the available testing technology and public health considerations regarding the utility of mass screening.
Technical Hurdles in Antibody Testing
The primary reason herpes is not a standard screening test relates to the limitations of the blood tests used to detect past infection. Unlike tests for other STIs that identify the active presence of bacteria or a virus, the routine herpes test is a serological assay that looks for antibodies the body has produced in response to the virus. These antibodies, specifically Immunoglobulin G (IgG), can take weeks to months to develop after initial exposure, meaning a test performed too early could result in a false negative.
Serological tests also face challenges distinguishing between the two virus types and the site of infection. While Herpes Simplex Virus Type 1 (HSV-1) is often associated with oral cold sores, it increasingly causes genital herpes; HSV-2 is the major cause of genital infection. A positive result for HSV-1 antibodies does not indicate if the infection is oral or genital, limiting the clinical usefulness for asymptomatic screening.
Inaccurate results are a significant problem, particularly in populations with low infection prevalence. Serological assays for HSV-2 have low specificity, leading to a high rate of false-positive results in the general population. These false positives cause unnecessary anxiety and potential relationship distress.
The Population Health Rationale
The public health policy against universal herpes screening is based on a cost-benefit analysis where the harms of screening outweigh the benefits. Unlike curable STIs like chlamydia or gonorrhea, which can cause severe long-term damage like infertility, herpes is a chronic, lifelong infection with no cure. Available treatment focuses only on managing symptoms and reducing the frequency of outbreaks.
Identifying an asymptomatic infection does not significantly change herpes transmission rates. The diagnosis often leads to substantial psychological distress, including anxiety and relationship disruption, without a clear clinical action to improve health outcomes. The U.S. Preventive Services Task Force (USPSTF) has consistently concluded that the potential harms of routine serologic screening for genital HSV infection in asymptomatic adolescents and adults outweigh the potential benefits.
The cost of implementing and interpreting a mass screening program, including necessary follow-up for counseling and confirmatory testing, would be substantial. This cost is difficult to justify when screening does not lead to a significant reduction in transmission rates on a population level. This policy aligns with the Centers for Disease Control and Prevention (CDC), which does not recommend routine serologic screening for HSV-2 in asymptomatic individuals.
Current Recommendations for Screening
While universal screening is not recommended, testing is performed in specific, targeted situations. Testing is advised for individuals who present with symptoms, such as unexplained genital or anal lesions or ulcers, to confirm the diagnosis and type of virus. In these cases, a swab taken directly from the lesion for viral culture or nucleic acid amplification testing (NAAT) is the preferred diagnostic method.
Serological blood testing is appropriate for individuals without symptoms who are considered to be at high risk or for specific clinical management decisions. This includes persons who have a sexual partner with known genital herpes, which helps in counseling for risk reduction. Testing may also be considered for people being evaluated for other STIs, particularly those with multiple partners or a history of high-risk sexual behavior.
For pregnant women, routine HSV-2 serologic screening is not recommended, but type-specific tests may be useful in specific scenarios to assess risk. For example, a pregnant woman whose partner has genital herpes may be tested to determine her susceptibility to infection, which is a factor in preventing neonatal transmission. The focus of current guidelines is on targeted, risk-based testing rather than mass screening.