What is the recommended pre-exposure prophylaxis (PrEP) for genital herpes?

Pre-Exposure Prophylaxis for Genital Herpes

There is no established pre-exposure prophylaxis (PrEP) regimen for genital herpes, and antiviral medications are not recommended for preventing HSV acquisition in uninfected individuals. 1, 2

Prevention Strategies for HSV-Negative Individuals

The focus for preventing genital herpes acquisition centers on behavioral interventions and partner management rather than pharmacologic prophylaxis:

Partner Testing and Disclosure

• HSV-2-seronegative persons should request that sexual partners undergo type-specific serologic testing before initiating sexual activity, as disclosure of HSV-2 status in heterosexual discordant couples was associated with reduced transmission risk 1
• Type-specific serology can identify asymptomatic HSV-2-infected partners who may transmit infection during periods of asymptomatic viral shedding 1, 2

Barrier Protection

• Consistent use of latex condoms reduces HSV-2 acquisition from women to men and from men to women and should be encouraged for all sexual exposures with new or potentially infected partners 1, 3
• Condoms provide partial but not complete protection, as HSV can be transmitted from areas not covered by condoms 3, 4

Avoidance During Symptomatic Periods

• Sexual contact must be avoided when partners have visible genital or orolabial herpetic lesions 1
• However, recognize that 85-90% of HSV-2 transmission occurs during asymptomatic viral shedding when no lesions are present 3, 5

Partner Suppressive Therapy (Not PrEP for the Uninfected Individual)

While not pre-exposure prophylaxis for the uninfected person, suppressive antiviral therapy in the HSV-2-infected partner reduces transmission risk:

• Valacyclovir 500 mg once daily in the infected partner reduced HSV-2 transmission to susceptible heterosexual partners by 48-50% in discordant couples 1, 3
• This approach has been studied in HIV-negative heterosexual couples; effectiveness in reducing transmission from or to HIV-positive persons has not been evaluated 1
• The infected partner should receive daily valacyclovir combined with condom use and safer sex counseling 4

Critical Distinctions and Pitfalls

Why No True PrEP Exists

• Unlike HIV PrEP, no antiviral medication has been studied or approved for administration to HSV-negative individuals to prevent acquisition 2, 6
• The dose, duration, and efficacy of antiviral prophylaxis after exposure to HSV have not been evaluated 1

Common Misconceptions to Avoid

• Do not prescribe antivirals to uninfected individuals hoping to prevent HSV acquisition—there is no evidence supporting this practice 1
• Do not rely on absence of visible lesions as indication of non-infectiousness; asymptomatic shedding accounts for one-third of viral shedding days and occurs in the majority of HSV-2-infected persons 3
• Routine serologic screening is not recommended in asymptomatic individuals 2, 4

Risk Stratification Considerations

• HSV-2-positive individuals have higher risk of acquiring HIV infection, making prevention of HSV-2 particularly important in high-risk populations 5
• Asymptomatic viral shedding is most frequent during the first year after the infected partner's initial infection 3

Practical Algorithm for Counseling HSV-Negative Patients

For patients seeking to reduce HSV acquisition risk:

1. Request partner testing with type-specific HSV serology before sexual activity 1
2. If partner is HSV-2 positive: Recommend partner initiate suppressive valacyclovir 500 mg daily 1, 3
3. Use condoms consistently during all sexual encounters 1, 4
4. Avoid sexual contact during any symptomatic outbreaks (genital or oral lesions) 1
5. Counsel that no intervention completely prevents transmission, even with all precautions 3, 4