Study: 30,000 Sex Acts Between HIV-Mixed Partners Result in Zero New Infections

published on July 17, 2016 by David Heitz, in healthline

Though sex between partners with different HIV statuses very rarely spreads HIV, experts warn not to throw caution to the wind.

A large-scale study that has documented more than 30,000 sex acts between HIV mixed, or serodiscordant, gay and straight couples has detected zero transmissions of the HIV virus.

All of the HIV-positive partners are on life-saving antiretroviral therapy (ART) and have suppressed viral loads of less than 200 copies per milliliter of blood. Levels are called “undetectable” when they fall below 50 copies per milliliter. All of the HIV-positive study participants had been on ART for at least five years. About 90 percent had healthy CD4 T-cell counts.

Researchers at University College London are overseeing the study, known as Partner. It follows couples at 75 sites in 14 European countries. It requires participants to have condomless sex, and the HIV-negative couples must not be taking medications for pre-exposure or post-exposure prophylaxis.

These findings confirm the results of a famed 2011 study known as HPTN 052. That study, looking almost exclusively at heterosexual couples, showed that taking ART reduced the risk of HIV transmission by 96 percent.

Alison Rodger of University College London presented the preliminary Partner findings last week at the Conference on Retroviruses and Opportunistic Infections in Boston. The big news is that we now know the HPTN findings also apply to gay men and anal sex.

The findings have not yet been published in a peer-reviewed journal. And they do not necessarily mean that there is zero risk of contracting HIV from a medicated person with the disease who has a suppressed viral load and healthy T-cell counts.

So What's the Real Risk of Spreading HIV?

The study followed more than 700 couples, 39 percent of them gay men. The gay couples reported only 1.5 years of condomless sex, while the heterosexual couples reported having sex without condoms for about twice that long.

During the study, an undisclosed number of HIV-negative partners became positive. But genetic testing revealed that all of those infections came from someone other than their partner. The total number of infections will be disclosed at the end of the study in 2017, Rodger said.

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Study: 30,000 Sex Acts Between HIV-Mixed Partners Result in Zero New Infections

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