UPDATE COMING We’re currently working to update this article. Studies have shown that a person living with HIV who is on regular antiretroviral therapy that reduces the virus to undetectable levels in the blood is NOT able to transmit HIV to a partner during sex. This page will be updated soon to reflect the medical consensus that “Undetectable = Untransmittable.”

The idea of a sexual relationship with someone who was HIV-positive was often considered off-limits in the early days of the AIDS epidemic. Now mixed-status couples, also known as serodiscordant couples, can enjoy satisfying sexual relationships and even conceive children with minimal risk of transmitting the disease. But HIV remains an incurable disease. Serodiscordant couples still need to make smart decisions about sex.

How risky is sex with a partner who is HIV-positive?

HIV is transmitted through bodily fluids. These include blood, semen, and vaginal and rectal excretions. HIV cannot be passed to another person by touching or closed-mouth kissing.

The realities of the disease can get in the way of an intimate relationship. This is especially true for couples who want to have children. The virus can be passed from an infected partner to another, even when the viral load is undetectable.

The good news is that recent medical advances have serodiscordant couples talking about sex again.

Prevention as treatment

In 2011, The New England Journal of Medicine published an international study known as HPTN 052. The research found that antiretroviral therapy (ART) does more than stop replication of the virus in people with HIV. It also lowers the risk of transmitting the disease to someone else. Most people in the United States begin ART upon diagnosis of HIV.

The study looked at more than 1,700 couples, most married and heterosexual. Almost all of the couples reported using condoms during sex and all received counseling. Infection risk was reduced by 96 percent among the couples who began ART early.

Protect yourself

Partners who are HIV-negative can protect themselves by taking a medication called pre-exposure prophylaxis (PrEP). PrEP is another way of prescribing Truvada. This is a pill used to treat people who already have HIV. A once-a-day regimen has proven effective at preventing infection in people without HIV.

PrEP medication only works if it’s taken exactly as directed. One study of men who have sex with men showed that the medication reduced transmission in couples by 44 percent, according to the Centers for Disease Control (CDC). The study included participants who did not take the medication regularly. Not taking it regularly reduces the pill’s effectiveness.

Studies among people at high risk of infection have shown risk reductions from PrEP of as much as 92 percent. Many insurance companies pay for PrEP for at-risk people, and may cover individuals in mixed HIV-status relationships.

Common sense is a must

Recent medical breakthroughs do not mean that people in serodiscordant relationships are free to have sex without taking precautions. HIV may still be present in semen and vaginal and rectal fluids. This can even be the case for people with an undetectable viral load.

Condoms offer protection in addition to medications. The possibility of infection is reduced if you use a condom the correct way every time you have sex. The more sex you have, the greater your risk may be for HIV transmission.

Having children

Serodiscordant couples who want to have children have many options available for safe conception and delivery.

A man with HIV can have his sperm certifiably stripped of the virus in a laboratory. This can help protect a woman who is HIV-negative. The sperm can then be implanted into a partner or surrogate mother.

Heterosexual couples who want to have a baby via sexual intercourse can take precautions to reduce risks. Consult your doctor to explore your options.

Conception the natural way

A partner with HIV may be on ART and have a partner who is HIV-negative and takes PrEP. Risk for HIV transmission remains low in this situation, even without a condom. But sex without a condom needs to be rare and should only occur during times of peak fertility. And both partners need to be on the proper medication.

The chances for HIV transmission from a mother to her baby is greatly reduced if the mother is on ART before and during conception and delivery. Risk is further reduced when the baby is delivered by cesarean birth and the mother avoids breast-feeding. Combined, all of these measures result in a significantly reduced chance of having a baby who is HIV-positive.

HIV today

In the past many people might not have considered partnering with someone with a different HIV status. HIV transmission concerns and the potential of losing a partner to AIDS often drove this decision. And attitudes toward people in mixed relationships might have added further strain.

People with HIV can now be expected to live long and healthy lives with the right treatment. And antistigma campaigns have made it easier for mixed-status couples to talk openly about HIV.