Does a positive Herpes Simplex Virus 2 (HSV2) test result indicate genital herpes?

Does a Positive HSV-2 Test Indicate Genital Herpes?

Yes, a positive HSV-2 (Herpes Simplex Virus type 2) test strongly indicates genital herpes infection, though approximately 20% of HSV-2 seropositive individuals may be asymptomatic and unaware of their infection. 1

Understanding HSV-2 and Genital Herpes

HSV-2 is predominantly associated with genital herpes infections. The relationship between HSV-2 and genital herpes can be understood through these key points:

• HSV-2 is the most common cause of genital herpes, with approximately 70% of HIV-infected persons being HSV-2 seropositive 1
• While HSV-1 can also cause genital herpes, HSV-2 is much more likely to cause genital infections and recurrent episodes 1
• About 80-90% of genital herpes cases progress subclinically (without noticeable symptoms), but may become symptomatic at any time 1
• Even in asymptomatic individuals, the virus can reactivate and be transmitted to sexual partners 1

Clinical Presentation of Genital Herpes

Genital herpes presents with varying degrees of severity:

• Classic symptoms: Vesicular and ulcerative lesions on genitals, buttocks, or thighs
• Other symptoms: Dysuria, vaginal or urethral discharge, inguinal lymphadenopathy
• Recurrent episodes: Typically begin with localized redness, followed by papular then vesicular rash
• Duration: Episodes usually last less than 10 days without treatment 1

However, it's crucial to understand that most HSV-2 infections (80-90%) progress subclinically, meaning patients may have no recognizable symptoms despite being infected and potentially contagious 1.

Diagnostic Considerations

When interpreting a positive HSV-2 test, consider:

1. Test accuracy: HSV-2 serologic testing has high sensitivity (92%) but specificity varies with the test used 1
2. False positives: Can occur, particularly with low index values (1.1-2.9) 1
3. Confirmation: For low positive results (index value <3.0), confirmation with a second assay using a different gG antigen is recommended 1
4. Window period: False negatives may occur if testing is done within 12 weeks of exposure 1

Clinical Algorithm for Managing Positive HSV-2 Results

1. For symptomatic patients with positive HSV-2:

   • Confirm diagnosis with viral culture or PCR if active lesions are present 1, 2
   • Offer treatment options:
     • Suppressive therapy (daily medication to prevent recurrences and transmission)
     • Episodic therapy (short-term therapy for symptomatic recurrences) 1
   • Provide counseling about transmission risk and prevention strategies

2. For asymptomatic patients with positive HSV-2:

   • Confirm high-index value results (≥3.0) are generally reliable 1
   • Consider confirmatory testing for low-index values 1
   • Educate that approximately 20% of HSV-2 seropositive individuals have no symptoms 1
   • Counsel about potential for asymptomatic viral shedding and transmission 3

Important Caveats and Pitfalls

• Don't assume no symptoms means no infection: Approximately 20% of HSV-2 seropositive individuals never develop recognized symptoms 1
• Don't rely solely on clinical diagnosis: Laboratory confirmation is essential as clinical differentiation from other causes of genital ulceration is difficult 1
• Don't dismiss psychological impact: While studies show no lasting adverse psychosocial impact of HSV-2 diagnosis in most individuals, initial counseling is important 4
• Don't forget about transmission risk: Asymptomatic shedding is a major source of continued HSV-2 transmission 5

Conclusion for Clinical Practice

A positive HSV-2 test should be interpreted as evidence of genital herpes infection, even in the absence of symptoms. The focus should be on appropriate counseling about the nature of the infection, potential for transmission even during asymptomatic periods, and discussion of treatment options to reduce symptoms and transmission risk.