What should I tell a patient after a single unprotected sexual encounter with a partner who may have genital herpes regarding post‑exposure management, testing, and prevention?

Post-Exposure Counseling After Potential Herpes Exposure

After a single unprotected sexual encounter with a partner who may have genital herpes, reassure the patient that immediate post-exposure prophylaxis is not indicated, but provide comprehensive counseling about transmission risk, testing timeline, and prevention strategies for future encounters. 1

Immediate Post-Exposure Management

No prophylactic antiviral therapy is recommended after potential HSV exposure. Unlike other sexually transmitted infections where post-exposure prophylaxis is standard (such as HIV or bacterial STIs), there is no established role for preventive antiviral treatment after herpes exposure. 2, 1

What to Monitor For

• Counsel the patient to watch for symptoms of primary HSV infection, which typically appear 2-12 days after exposure and may include painful genital vesicles or ulcers, dysuria, tender inguinal lymphadenopathy, and systemic symptoms like fever and malaise. 1
• Emphasize that if any genital lesions develop, the patient should seek immediate medical evaluation for viral culture or PCR testing, as diagnosis is most accurate when lesions are present. 1
• Explain that many HSV infections are asymptomatic or have minimal symptoms that go unrecognized, so absence of symptoms does not guarantee they were not infected. 1, 3

Testing Strategy and Timeline

Do not perform immediate HSV serologic testing, as it cannot detect acute infection and will only reflect pre-existing antibody status. 2

Recommended Testing Approach

• Offer type-specific HSV serologic testing (HSV-1 and HSV-2 antibodies) at 12-16 weeks after the exposure, as antibodies may take 3-4 months to develop after new infection. 2
• Explain that a positive HSV-2 antibody test at that time could represent either new infection from this exposure or pre-existing unrecognized infection. 1
• If the patient develops any genital lesions before that time, they should return immediately for PCR or viral culture testing of the lesion, which is the preferred diagnostic method during symptomatic episodes. 1, 4

Additional STI Screening

• Since the encounter was unprotected, screen for other sexually transmitted infections including HIV, syphilis, gonorrhea, and chlamydia at the initial visit and repeat at appropriate intervals per CDC guidelines. 2
• Offer hepatitis B vaccination if the patient is not already immune. 2

Critical Counseling About HSV Transmission

Understanding Asymptomatic Transmission

• Most HSV-2 transmission occurs during asymptomatic periods when no visible lesions are present, which is the primary mode of spread and why many people unknowingly transmit the virus. 5, 6
• Asymptomatic viral shedding occurs on approximately 10-20% of days in infected individuals, even when they have no symptoms or visible lesions. 5, 6
• Approximately 85-90% of people with genital HSV-2 infection are unaware they have it because their symptoms are minimal or unrecognized. 5, 6

If the Patient Becomes Infected

If the patient develops primary genital herpes, initiate antiviral therapy immediately with valacyclovir 1 g orally twice daily for 7-10 days. 1

• Alternative first-episode regimens include acyclovir 400 mg orally three times daily for 7-10 days or famciclovir 250 mg orally three times daily for 7-10 days. 1
• Treatment may be extended beyond 10 days if healing is incomplete. 1
• Provide comprehensive counseling that HSV is a chronic, lifelong infection that cannot be cured, but symptoms can be effectively managed with antiviral medications. 1, 7

Prevention Strategies for Future Sexual Activity

Risk Reduction Methods

• Consistent condom use reduces but does not eliminate HSV transmission risk, as the virus can be present on skin not covered by condoms. 5, 6
• If a future partner has known HSV-2 infection, the infected partner should take daily suppressive valacyclovir 500 mg once daily, which reduces transmission risk by approximately 48-50%. 5, 6
• Combining daily suppressive therapy in the infected partner with consistent condom use provides the greatest risk reduction, though neither strategy eliminates transmission entirely. 5, 6
• Avoid all sexual contact when visible lesions or prodromal symptoms (tingling, burning) are present, though recognize this alone does not prevent transmission. 1, 5

Partner Communication

• Encourage open communication with sexual partners about HSV status before initiating sexual activity. 1
• Consider requesting that new partners undergo type-specific HSV serologic testing before sexual activity begins. 5
• Understand that many partners may be unaware of their HSV status, as most infections are undiagnosed. 5, 6

Common Pitfalls to Avoid

• Do not assume that avoiding sex only during visible outbreaks is sufficient, as the majority of transmission occurs during asymptomatic periods. 5, 6
• Do not rely on non-type-specific antibody tests or IgM testing, as these are unreliable and can give false results. 2
• Do not prescribe episodic antiviral treatment thinking it reduces transmission risk—only daily suppressive therapy has been shown to reduce transmission. 5
• Do not perform serologic testing immediately after exposure, as it will not detect new infection and only reflects pre-existing antibody status. 2

Special Considerations for Women of Childbearing Age

• If the patient is female and of childbearing potential, counsel about the risk of neonatal herpes if she becomes pregnant in the future. 1
• Emphasize the importance of informing obstetric providers about any HSV infection during pregnancy. 1, 5
• The highest risk to the newborn occurs with primary maternal infection during the third trimester, making prevention of new infection particularly important during pregnancy. 1

Psychosocial Support

• Acknowledge that concerns about potential HSV infection can cause significant anxiety and stress. 8
• Reassure the patient that if infection occurs, effective treatments are available that dramatically reduce symptoms and recurrences. 1, 8
• Provide resources for additional information and support, as the psychological impact of genital herpes can be substantial. 8