The confusing science behind Herpes testing and transmission

I saw the message preview first. “James* mentioned you slept together and h…”

“Oh, shit,” I thought. This was James’s soon-to-be ex wife messaging me about the fairly recent hookup I’d had with her husband. There’s nothing inherently wrong with the fact that I slept with her husband. That’s the sort of stuff we non-monogamous people do, consensually, all the time. However, I could tell from the tone that she was mad. I was afraid that something in their relationship had changed, and I had unknowingly crossed a line. I clicked the message.

“…and he didn’t disclose he has herpes. He’s irresponsible. You should know he’s positive since you throw sex parties.”


He hoped it was a false positive, and chose not to disclose that information to me before we had sex. His doctor even told him he probably didn’t need to tell anyone because the chances of a false positive are high.

My hands are still shaking as I write this from the anger and fear that swept over me. Have I gotten my husband sick? I did notice two cold sores lately, which is unusual for me. I figured they were zits from using too much Carmex. Did I ignore the signs? My tests have always shown that I do not carry HSV-1. HSV-1 is also known as oral herpes and ridiculously common — 80% of the population has this virus. It’s the primary culprit of cold sores, though about 40% of genital herpes is caused by HSV-1 due to oral-to-genital sex.

But Tanya* was talking about HSV-2, commonly known as Genital Herpes. HSV-2 is less common than HSV-1, and sounded much more scary to me. How could James not disclose this to me? I was at their wedding. I donated to their honeymoon fund. How could he be so cavalier with my health?

I wasn’t sure I believed her. They’re getting divorced; I’ve heard people say worse lies about each other in the middle of nasty divorces. Her brief message felt like a callous way of informing me that my health might be compromised. She could have picked up the phone instead of dropping that bombshell in Facebook Messenger. So perhaps she is just angry, and this isn’t really happening. I messaged James.

“Hey man, hope this finds you well. Listen, Tanya just sent me a slightly alarming message on Facebook messenger. She’s probably just mad at you, but I wanted to let you know what’s going on.”

Within 10 seconds, my phone was ringing. Yes, he’d had one positive test for HSV-2 in the last 6 months, but he’s had a more recent negative test. He hoped it was a false positive, and chose not to disclose that information to me before we had sex (protected vaginally, unprotected orally.) His doctor even told him he probably didn’t need to tell anyone because the chances of a false positive are high. My ears were ringing and it was getting harder to hear him.

I held my voice steady. I wanted to give positive feedback that telling me now was a good thing, even though waiting to tell me until this point was not. (In fact, failure to disclose is a criminal offense in California.) Since his test results conflicted, I sent him our list of testing locations in the SF Bay area. I sent my go-to resource for how to inform your partners that you have an STD or STI. As a community organizer, It’s my job to handle these kinds of discussions calmly, and focus on actionable next steps before finding fault and blame. They just don’t usually involve my own health.

We treat disclosures with compassion and respect in our non-monogamous community. No one is going to slap you across the face, or run screaming in the opposite direction if you disclose that you have an STD or STI. We explicitly discuss our STD & STI policy with new members, and we reiterate that policy at every single event.

I’m aware of many people in the community who are positive, for a variety of STDs and STIs. I also know that they have been able to responsibly disclose that information to potential partners at sex events and still get laid. In an environment like ours, (and really, in any environment,) there is zero excuse for not knowing your status or failing to disclose your status.**

The Dark Arts of testing for Herpes

I was tested the day after I received the news. The doctors were a little irritated with how freaked out I was. Medically speaking, Herpes is a mild skin condition, and really not a big deal (though active outbreaks during childbirth introduce risk.) Even if were to get a positive result, that was not going to be the biggest health crisis they faced that day, or any day. As far as things you might need to go to a doctor for, if you are an otherwise healthy person, then this is barely on their radar of actual health problems.

I was told the results would take “7 – 9 business days.” The doctor says I can’t really be sure for another few months, as the results are unreliable. How unreliable? She wasn’t sure.

There is significant pushback from the medical community to not test for Herpes in asymptomatic patients. This seemed so bizarre to me. Obviously, if I have good reason to believe I’ve been exposed to this virus, I should be tested… right?

I asked a lab technician who runs the tests about the first detection times. There are only two ways to test for Herpes — blood tests, that looks for antibodies created due to the presence of the virus, and skin cultures, where blisters are cultured to look for the virus (called a “viral culture of lesion test.”) If you are asymptomatic — meaning you don’t have any blisters or lesions — your only option is an antibody test.

As it was explained to me (first by the lab tech, and later by a doctor reviewing this article for accuracy), antibody testing is A.) expensive, and B.) woefully inconclusive. Because of this, there is significant pushback from the medical community to not test for Herpes in asymptomatic patients. This seemed so bizarre to me. Obviously, if I have good reason to believe I’ve been exposed to this virus, I should be tested — right? Even if the results are a little iffy? Isn’t that what any responsible person would do if they could afford it?

The Herpes simplex PCR test (a blood test) detects the genetic material in your blood before you develop blisters or lesions. The blood test for HSV2 has a “positive predictive value” of 50%. What this means is that they are equally likely to be a false positive vs. a real positive. That is completely useless information. Really the only way to be highly confident that you have contracted genital HSV-1 or HSV-2 is to have blisters swabbed, and by that time the doctor can basically already tell you at-a-glance “yep these blisters are Herpes.”

There is one slightly more accurate antibody test called the Western Blot test. It’s offered at exactly one lab in the entire united states, and it’s $280. At one point while writing this article, I actually deleted this paragraph because I do not want anyone reading this to run out and pay $280 for that test. It’s just too inconclusive.

Given that every HSV-2 blood test are infamously inaccurate and Herpes is incurable, I better understand my doctor’s attitude of “let’s not cause stress and stigma where it’s not needed.” However, that philosophy breaks down when you have multiple partners and want to be sure they are aware of any risks they’re exposing themselves to. If you can’t even know if you’ve contracted the virus or not, how can you responsibly inform your partners about their risk?

How likely are you to transmit Herpes to partners? Science isn’t sure.

Since I received the news very late at night, I waited until 6am to inform my other partners of their possible exposure. (And calling at 6am was definitely overkill. If you’re really worked up, it’s okay to take a day to collect yourself before informing your sexual partners, But you do need to do it soon.)

You see, in the few weeks since James failed to inform me, I had sex with two women and my husband, without protection. Those people were all put at risk without their consent because of James’s failure to disclose. But how much risk?

If you use barriers, avoid sex when symptomatic, and take antiviral drugs, then transmission likelihood is “low” — and that’s about as specific as you can get.

A buddy of mine, who is also HSV-2 positive, was just telling me that transmission rates are low when you are asymptomatic. I decided to find out how low. I wound up on the CDC detailed fact sheet. There is no transmission rate mentioned on this page. What I did find here was that “In persons with asymptomatic HSV-2 infections, genital HSV shedding occurs on 10.2% of days.” So, perhaps a 10% chance of infection? However, ”The first outbreak of Herpes is often associated with …increased viral shedding (making HSV transmission more likely).” How much more likely? Doesn’t say. I assume that a diagnosis 6 months ago means we’re still in that increased viral shedding period… right? Why are there so few answers for the questions I desperately needed answered?

Continued Googling found this PDF, which includes unprotected transmission rates, but not protected transmissions rates. It did calm one fear that I’d had, about having oral sex with James without a condom. According to this, the chance that I have oral HSV-2 is only 1%. I finally, and thankfully, found this resource which states:

“Let’s say you have an infected male and an uninfected female. If they avoid sex during outbreaks, don’t use condoms regularly, and don’t take antiviral therapy every day, the risk of transmission is about 10% per year. But if you add condoms, it reduces transmission by about 50%, if he takes valacyclovir (Valtrex®) 500 mg once a day, he can reduce transmission also by about 50%. So you can see that the numbers get very low! If it is a woman infected with HSV 2 having sex with an uninfected male, given the circumstances listed above again, then the transmission rate is about 4% prior to the interventions of condoms and Valtrex®.”

I am suspect of sites that sing the praises of a specific drug, but a doctor I spoke with explained that Valtrex (generic name Valacyclovir) is simply the best and most convenient medication for this. The alternative, Acyclovir, must be taken orally multiple times per day whereas Valacyclovir/Valtrex can be taken just once daily, which is much more sustainable.

Finally, I found this study about the “Effect of Condoms on Reducing the Transmission of Herpes Simplex Virus Type 2 From Men to Women.” TL;DR — lots of math, but “Condom use offers significant protection against HSV-2 infection in susceptible women.”

The moral of all of this? There is shockingly little reliable information about HSV-2 transmission rates. There are 4 factors that impact transmission: Barriers (i.e. condoms, dental dams, and female condoms), viral outbreaks, antiviral drugs, and the genitalia of the uninfected person. People with female genitalia are at greater risk of becoming infected by a partner, presumably because of the increased amount of mucus membrane exposure.

Given all the research we have about transmission for each of these 4 factors, the most accurate measurements for risk of HSV-2 transmission during a single sexual encounter is probably just, “low,” “medium” or “high.” And as of this article written in 2014, “there is no available data yet on the rate of transmission between same-sex couples.” If you’re like me, you probably find that extremely unsatisfactory.

So how do you prevent transmission to the people you care about? Well, if you use barriers (like condoms and dental dams), avoid sex when symptomatic, and take antiviral drugs, then transmission likelihood is “low” — and that’s about as specific as you can get.

Non-monogamy and transmission

None of the resources I found discussed transmission risk outside of monogamous relationships. In fact, the CDC’s first recommendation for how to reduce your risk of transmission was “being in a long-term mutually monogamous relationship with a partner who has been tested and has negative STD test results” a statement which is at best unrealistic and at worst, flat-out discriminatory. Many people are not sexually monogamous.

James isn’t a regular partner, just an occasional one. Does that mean my infection risk is even lower? And even for a monogamous person, the variance for how much a given couple has sex in a year is wide. 200 times and 30 times are probably both within a “normal” range. The transmission rates listed in this study were over a year of unprotected sex between partners, but the number of encounters wasn’t considered. What is the risk of transmission per sexual encounter, protected or unprotected? “Less than 10%” feels encouraging, but not enough data for me to feel informed.

The footnotes on that page linked to this study. I was surprised that this was the only study I could find on HSV transmission, but more surprised at the small sample size. Only 144 couples participated, and the abstract doesn’t even mention if these couples proclaim to be monogamous. Because I’m extremely type A, I immediately contacted a friend who is a neuroscientist and asked her to download the full text of the article from PubMed for me.

The study is from 1992, and I haven’t been able to find a single more recent study on the topic of HSV-2 transmission rates. (If you can find this, please email me.) The sample group was “hetero- sexual, predominantly white, monogamous couples.” Welp, I’m not heterosexual or monogamous, and I’m really not sure what being “white” or not has to do with STD transmission so… this generally displeased me.

In the end, I didn’t end up knowing nearly as much as I was hoping about HSV transmission. I do know that my consent has been violated by someone I trusted. While I could pursue legal action, it would probably be hard to explain to most judges that A.) yes we’re both married but B.) no we weren’t cheating, C.) yes we are both sexually active in an “aberrant” way but D.) no, that does not mean we “deserve” to get sick or “should have seen it coming.” Also, “sex party host sues guest for giving her STD” is a headline I don’t need my picture next to.

Both by IgG and IgM blood test results came back negative, but it takes “3-6 months for your body to make IgG antibodies in response to an infection,” and these tests are only 80% — or maybe 50% — accurate anyway. So I will be tested again at 3 and 6 months. (Editorial update — additional testing continues to come back negative.) Interestingly, James was also tested again, at this point 6 months past his initial positive test, and his results came back negative a second time, so I suspect his first test was indeed a false positive. In fact, I suspect that there are a lot of asymptomatic people with false HSV-2 positive results. But I’m glad for this experience, so that I could write this article. Suspecting that your results are a false positive is not an excuse to fail to disclose that information. You don’t have the luxury of denial when other people’s health is on the line.

You’re a wonderful person, and everything is going to be okay.

If you have been diagnosed with genital HSV, I’d actually argue that your sex life is actually going to get better, since you will now only be sleeping with people who want you so much that they’ll take the risk. Really this is a great opportunity to weed out lousy hookups. All kidding aside, here are some wonderful articles that some very brave and insightful people with HSV-2 have written about their experience:


*Names changed to protect my idiot friends.

** Your health and safety come first. If you believe that someone will hurt you if you disclose this information, do not put yourself in danger. There are ways to inform your partners and remain anonymous. If you can inform anonymously and stay safe, please try to use these anonymous disclosure options:

If you do not believe there is any safe way to inform your partner without retaliation, don’t. That is the one and only excuse for not informing your partners about a positive status.