From the Guidelines
Yes, taking antiviral medication before sex can help prevent HSV-2 transmission, and the most recent and highest quality study recommends suppressive therapy with antivirals such as valacyclovir, acyclovir, or famciclovir 1. The most commonly prescribed antivirals for HSV-2 suppression are:
- Valacyclovir: 500 mg daily
- Acyclovir: 400 mg twice daily
- Famciclovir: 250 mg twice daily Take the medication daily as prescribed, even when you don't have symptoms. It reduces viral shedding and lowers transmission risk by about 50% 1. However, it doesn't eliminate the risk entirely, so using condoms is still recommended. Some key points to consider:
- Suppressive therapy can be considered to prevent transmission in all populations, including men who have sex with men, women who have sex with women, and transgender persons 1.
- However, suppressive therapy is not effective to decrease the risk of transmission among persons with HIV/HSV-2 coinfection 1.
- The use of suppressive antiviral therapy in persons with genital herpes reduced HSV-2 transmission to susceptible heterosexual partners by 50% 1.
- Daily anti-HSV suppressive therapy in HIV-infected persons also results in a decrease in HIV concentration in plasma and anal and genital secretions 1. Start suppressive therapy at least 5 days before potential sexual exposure for maximum effectiveness. Continue taking it daily for as long as suppression is desired. Discuss with your doctor to determine the best regimen for your situation. These antivirals work by interfering with viral DNA replication, reducing outbreaks and asymptomatic viral shedding. This makes transmission less likely, though not impossible. It's also important to note that genital herpes is a chronic sexually transmitted infection, and accurate diagnosis can be realized using type-specific molecular or virologic tests when genital ulcers are present, and type-specific serologic test to detect antibody when lesions are not present 1.
From the FDA Drug Label
The efficacy results are summarized in Table 7. Table 7. Percentage of Susceptible Partners Who Acquired HSV-2 Defined by the Primary and Selected Secondary Endpoints Endpoint VALTREX a (n = 743) Placebo (n = 741) Symptomatic HSV‑2 acquisition 4 (0.5%) 16 (2. 2%) HSV‑2 seroconversion 12 (1.6%) 24 (3.2%) Overall HSV‑2 acquisition 14 (1.9%) 27 (3.6%) a Results show reductions in risk of 75% (symptomatic HSV‑2 acquisition), 50% (HSV‑2 seroconversion), and 48% (overall HSV‑2 acquisition) with VALTREX versus placebo.
Prevention of HSV-2 transmission: Valacyclovir can be taken to reduce the risk of transmitting HSV-2 to a partner.
- The recommended dosage for this purpose is 500 mg once daily 2.
- Patients should be counseled to use safer sex practices in combination with suppressive therapy with VALTREX 2.
- Valacyclovir has been shown to reduce the risk of HSV-2 transmission by 75% for symptomatic acquisition, 50% for seroconversion, and 48% for overall acquisition 2.
From the Research
Antiviral Therapy for HSV-2 Prevention
- The use of antiviral therapy, such as valacyclovir, has been shown to reduce the risk of transmitting genital herpes in heterosexual, HSV-2-discordant couples 3, 4.
- A study published in The New England Journal of Medicine found that once-daily suppressive therapy with valacyclovir reduced the risk of transmission of symptomatic genital herpes by 75% and the overall risk of acquisition of HSV-2 infection by 48% 3.
- Another study published in Herpes found that valaciclovir reduced the risk of transmitting HSV-2 infection by 48% and the risk of clinical disease in the susceptible partner by 75% 4.
Recommendations for Antiviral Therapy
- The International Herpes Management Forum recommends that physicians offer suppressive valaciclovir therapy to immunocompetent individuals concerned about transmitting genital herpes to a heterosexual partner 4.
- Daily suppressive therapy is recommended as a therapeutic option for HSV-2 seropositive individuals at risk of transmitting HSV-2 5.
- However, it is essential to note that no intervention completely protects against transmission of HSV, and infected individuals and their partners should be counseled to use safer sex practices, including the use of condoms 5, 6.
Limitations of Antiviral Therapy
- A study published in The Journal of Infectious Diseases found that daily suppressive therapy with acyclovir did not decrease the risk of HSV-2 transmission from HIV-1-infected persons to susceptible partners 7.
- This suggests that more-effective prevention strategies may be needed to reduce HSV-2 transmission from HIV-1-infected persons.