Reducing herpes transmission risk with Valtrex

Dear Alice,

I am a gay man, and my on-again, off-again boyfriend has genital herpes on his anus. He currently takes Valtrex to manage his symptoms (his outbreaks occur about once or twice a year). I love him and want to continue our relationship, but I also want to protect myself. Would taking Valtrex (or some other viral suppressing drug) reduce the chances of transmitting the disease to me?

Dear Reader,

Knowing your partner's sexual health status is essential to maintaining your own sexual health — so kudos to the both of you for connecting on a potentially sensitive subject! Valacyclovir (brand name: Valtrex) is an anti-viral drug approved for treating or managing a variety of conditions caused by viruses in the herpes family, including chickenpox, cold sores, and genital herpes. In the case of genital herpes specifically, valacyclovir is prescribed to help reduce the pain and duration of an outbreak, as well as decrease the number of outbreaks a person experiences over time. And, while it doesn’t fully prevent genital herpes transmission, it can reduce the risk. So, the short answer to your question is that your partner’s use of valacyclovir can reduce the risk of transmitting genital herpes to you. However, there are some caveats to consider, such as additional safer sex practices to further decrease the risk of transmission (more on that later). Also, it’s a bit unclear if your question is also asking whether you, as the uninfected partner, could take valacyclovir to reduce your risk of contracting the virus. To that end, it might be helpful to know that, at this time, valacyclovir is only approved for use in affected individuals and not for prophylactic reasons in those currently uninfected. 

Clinically, valacyclovir has been approved by the U.S. Federal Drug Administration (FDA) for reducing the risk of transmitting genital herpes to an uninfected partner when used in combination with safer sex behaviors. In other words, valacyclovir is effective at reducing the risk of partner-to-partner transmission when it's taken in addition to using barrier methods (such as condoms and dental dams), and when partners abstain from sexual contact if the affected partner is having an active herpes outbreak. While condoms are most effective at protecting parts of the body that they fully cover, they aren’t fail-safe — for example, areas that a condom or other barrier might not cover, such as the thighs, groin, or buttocks, can still be vulnerable to the herpes virus if active sores are present. Additionally, sometimes herpes can be passed onto a partner even if there aren’t any noticeable symptoms and even if condoms are used, due to asymptomatic viral shedding. What’s more, valacyclovir is only effective in preventing transmission if taken exactly as prescribed and it’s most effective when taken daily. Any stops and starts in your partner’s regimen can reduce how well the drug controls his symptoms, which can increase his risk of transmitting the virus to you.

It’s also worth mentioning that the body of clinical evidence supporting the use of valacyclovir for reducing transmission risk is largely based on studies with monogamous, heterosexual couples who are mostly in good health with functioning immune systems. The general consensus among the medical community is that more research is necessary to determine the drug’s effectiveness in preventing transmission among homosexual partners or individuals with compromised immunity (i.e., folks living with diseases like diabetes, HIV, or people undergoing certain treatments for cancer).

That said, the most current Sexually Transmitted Diseases Treatment Guidelines from the Centers for Disease Control and Prevention (CDC) mention that suppressive therapy (including a daily valacyclovir regimen) is likely to reduce transmission among men who have sex with men (MSM). In weighing the risks and benefits though, prescribing the drug to patients in these populations or with these conditions is at the discretion of a medical professional. With that in mind, you might consider encouraging your partner to talk with his health care provider about the benefits of valacyclovir in his specific case, and the provider may be able to offer additional advice about reducing the risk of transmission. 

Maintaining open communication about sexual health is critical to any healthy relationship, and it sounds like you and your partner are already working together to help protect one another. You do mention that the two of you have an on-again/off-again relationship, so you may also want to consider discussing whether either of you have additional sexual partners and whether you and your partner consistently practice safer sex. Because the risk of sexually transmitted infections (STIs; herpes included) can increase as your lifetime count of sexual partners increases, and having herpes can increase the risk of getting other STIs (including HIV), it’s wise to talk with your partner about safer sex practices in addition to valacyclovir therapy. If you’d like to learn more about what additional risk reduction methods might work best for you, consider making an appointment to speak with a health promotion specialist. For even more information and resources on herpes, STI testing, and how to start a conversation about safer sex, check out the Safer Sex category in the Go Ask Alice! Sexual and Reproductive Health archives. 

Hope this helps!

Last updated Feb 10, 2017
Originally published Sep 19, 2003

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