My partner tested positive for an STI, but I'm negative. Why?

Everything you need to know about discordant or sero-different STI results.
By
Katie Baskerville
 on 
Patient getting a HIV test from a doctor, the patient holds their hand outstretched, while the doctor pricks their finger.
Credit: Getty Images / Alex Levine

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Attending sexual health screenings can be a nail-biting experience. But, what happens when you test positive for a sexually transmitted infection (STI) and your partner doesn’t? 

You may automatically assume that this is because of cheating, that your partner may have slept with another person or had sexual contact outside of your knowledge, prior to testing. This might be true, but it's also not the only possibility. You should know that you can still test positive and negative as a couple when cheating didn’t take place.

Historically, this has been known as a discordant STI result, and it refers to a situation where a sexually active couple receives different negative and positive diagnoses after taking an STI test. The term is often used referencing long-term, harder-to-treat STIs, such as HIV, but can also be applied to other STIs like chlamydia, gonorrhoea, genital warts, and more.

Now, with efforts to try and destigmatise STIs, new language is arising. Katie Nambiar, medical director of HIV and sexual health charity the Terrence Higgins Trust, tells Mashable that "discord" implies a conflict or clash. Instead, medical professionals are trying to move towards the term "sero-different." "The two are interchangeable, but we're just trying to move towards kinder language," she says. 

How can one person get an STI and the other not?

Everyone's body is different. The same goes for our immune system. Some people’s network of cells, tissues, and organs are better than others at fighting infection and disease. This can be one reason why you might obtain a sero-different or discordant result. Simply put, your body has already fought off the virus before it’s had a chance to settle in. 

Another reason can be that it is lying dormant. While most people experience symptoms from STIs almost instantly, others can remain symptomless for years. This is known as a latency period.

Dr. Melanie Bone, an OBGYN and member of menstrual wellness company Daye's medical board, tells Mashable that some STIs like syphilis and genital herpes can go unnoticed for several years. "Once you have caught it," she says, "you may never get a flare of herpes ever, may get one episode, or get recurrent episodes. You may even get your first flare ten years after catching it."

This is why regular testing is important, but also why cheating isn’t the only possibility when it comes to understanding why you may have sero-different results. 

What if you (or your partner) receive sero-different HIV results?

Bone explains that if you or your partner receive a sero-different STI result, the first and most important thing is to get tested again in four weeks, and then in eight weeks. This is partly because of the time it can take for symptoms to rear their head, but also because you can still catch an untreated STI from your partner. 

"Having received one discordant STI result doesn't mean that you are forever immune to catching your partner's STI," Bone explains. "If you are in possession of such results, it is more important than ever to practice safe sex. Do keep in mind that condom-protected sex cannot protect from every STI — monkeypox, syphilis, and genital warts can still be passed on during protected sex."

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Safe sex can mean multiple things, too. Like having no genital or fluid contact, using dental dams, mutual masturbation and much more. It can also mean taking medication to prevent infection. In instances where HIV is found in sero-different results, couples will be given a full rundown on how to move forward and live with the condition.

"In the case of HIV, if follow-on screens come back positive, both partners will be asked to take antiviral medication (such as PEP or post-exposure prophylaxis)," Bone says. "The couple will also be instructed on how to practice protected sex going forward, and they might receive counselling on their fertility options going forward if they are in a long-term, committed relationship."

Either way, couples can live, full, happy and long lives together (filled with all kinds of amazing sex), as long as they’re both taking antiviral drugs and using protection. 

"HIV is a treatable, manageable condition," Nambiar explains. She says that early detection and knowing your status is crucial if you’re to manage the virus successfully. "If you pick it up and treat it early, then the impact to your life is actually very, very minimal," she says.

Can sero-different couples have biological children?

For people in a sero-different relationship, fertility can feel like a minefield. While some couples (or throuples) might feel like having children isn’t the right thing for them, others may face fertility struggles from medical conditions such as Polycystic Ovarian Syndrome (PCOS) or a low sperm count. That doesn’t mean, however, that natural conception is impossible, even with a positive HIV diagnosis. 

"It is possible that couples conceive through the use of 'sperm washing' — a method whereby individual sperms are separated from the semen, allowing for conception to take place without infection," Bone tells Mashable. 

Whether you are male or female with HIV, you can still conceive naturally, but it is important that antiretroviral therapy (ART) is used to lower the chances of passing on HIV to your child. This is because, without medical intervention like antivirals, passing on HIV can happen quite easily at any point throughout pregnancy or through breastfeeding.

However, sero-different parents may find that their child is born HIV-negative, but regular checks and consistently taking prescribed antivirals are enthusiastically recommended by doctors. "Be reassured if you're on treatment, then you can’t pass it on, there’s zero risk," Nambiar says.

What should I do if I'm HIV positive?

"First off, do not panic," says Bone. "Modern medicine has advanced to a point where you and your partner's relationship can largely continue undisturbed."

"Second, make sure you receive detailed guidance on re-testing, PEP, and antiviral drugs, as well as fertility," she advises. "If you feel that any of your questions are not being adequately answered, seek a second opinion."

"We are moving to eradicate HIV transmission, something we couldn't have dreamed of not that long ago. Times are changing for the better."

If you or your partner are affected by HIV, or are looking for support as a discordant or sero-different couple, there are some fantastic resources that can be found at the National Aids Trust

"People believe the myth that people that have HIV/AIDS are in a bad way. That it is a terrible condition that leads to a shortened lifespan, or to having to take oral medications with horrible side effects. But we've moved past that," Nambiar explains. "Now, we are moving to eradicate transmission, something we couldn't have dreamed of not that long ago. Times are changing for the better."

Nambiar reiterates that for people living with HIV, the only and easiest way to live with it is to know early on that you have contracted it. Don’t suffer in silence, because there is so much that can be done to help you live a happy, good life.

Topics Health

Mashable Image
Katie Baskerville

Katie Baskerville is a Welsh freelance writer and journalist covering sex, health and LGBTQIA+ culture from her small studio in south Bristol, UK. You can find her on Instagram, TikTok and Twitter.


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