Post-Exposure Prophylaxis for HSV-2
There is no established post-exposure prophylaxis regimen for HSV-2 with anticipated exposure within one week, as the dose, duration, and efficacy of antiviral prophylaxis after HSV exposure have not been evaluated. 1
Evidence for Lack of Post-Exposure Prophylaxis
The CDC explicitly states in their guidelines that the dose, duration, and efficacy of antiviral prophylaxis after exposure to HSV have not been evaluated 1, and prophylaxis of initial episodes of HSV disease is not recommended 1. This represents a critical gap in HSV-2 prevention strategies, as no validated protocol exists for individuals anticipating exposure within a short timeframe.
Prevention Strategies Instead of Prophylaxis
Since post-exposure prophylaxis is not established, the focus must shift to exposure prevention and risk reduction:
Primary Prevention Measures
- Consistent latex condom use during every act of sexual intercourse reduces HSV-2 acquisition from women to men and from men to women 1
- Avoid sexual contact when partners have overt genital or orolabial herpetic lesions, as this is the highest-risk period for transmission 1
- Request type-specific serologic testing of partners before initiating sexual activity, as disclosure of HSV-2 status in heterosexual HSV-2-discordant couples was associated with reduced transmission risk 1
Partner Suppressive Therapy (If Applicable)
If the anticipated exposure involves a known HSV-2-positive partner, suppressive antiviral therapy in the infected partner (valacyclovir 500 mg once daily) reduced HSV-2 transmission to susceptible heterosexual partners by 50% 1. However, this requires the source partner to be on therapy, not the susceptible individual seeking prophylaxis.
Important Clinical Caveats
Sexual transmission of HSV can occur during asymptomatic viral shedding, even when no visible lesions are present 1. This means that even with all preventive measures, transmission risk cannot be completely eliminated. The majority of HSV transmission occurs during these asymptomatic periods, making behavioral prevention strategies only partially effective.
The effectiveness of suppressive therapy in the infected partner for reducing HSV-2 transmission has not been evaluated specifically in HIV-seropositive persons (either as source or recipient) 1, which is an important limitation if either partner is HIV-infected.
What to Do If Exposure Occurs
If exposure has already occurred or is imminent and unavoidable, no validated post-exposure treatment exists 1. The focus should be on:
- Monitoring for symptoms of primary HSV-2 infection (painful genital ulcers, systemic symptoms, lymphadenopathy)
- Seeking immediate evaluation if symptoms develop, as first-episode genital herpes should be treated with antiviral therapy for 7-10 days 2, 3
- Type-specific serologic testing at baseline and 3-4 months post-exposure to determine if infection occurred 1