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Condomless sex can be “safe sex,” if viral load is undetectable, says Opposites Attract researcher

, by Emily Land

BETA is attending and reporting from the 2017 International AIDS Society conference on HIV Science this week in Paris, France from July 23 to 26—bringing you the latest news, updates, and research on HIV treatment and prevention.

Results from the Opposites Attract study, presented this week at the IAS 2017 conference, add to mounting evidence that people living with HIV, who have suppressed their viral loads to undetectable levels, do not transmit HIV to sexual partners. In a study with gay men in serodiscordant relationships, there were zero linked HIV transmissions when the HIV-positive partner was undetectable.

The study’s findings complement findings from similar studies with heterosexual people, bolster momentum generated by the Undetectable = Untransmittable (U=U) campaign, and demonstrate that HIV treatment prevents HIV transmission even in the presence of sexually transmitted infections.

What is treatment as prevention?

Opposites Attract was an observational cohort study that followed 343 serodiscordant (different HIV status) gay male couples in Australia, Thailand and Brazil. Couples were followed for an average of a year and a half per couple, and contributed 591 couple-years of information about how they were having sex (including instances of condomless anal intercourse), their HIV viral loads, and other HIV prevention strategies used.

There were no HIV transmissions between partners in the study when the HIV-positive partner had an undetectable viral load. Nearly 17,000 condomless anal sex acts were reported in the study, more than 12,500 which were protected only with undetectable viral load. There were three HIV infections during the study, which phylogenetic analyses revealed to have happened due to outside partnerships.

Andrew Grulich

Andrew Grulich, MBBS, PhD, from University of New South Wales in Australia

“The important finding is that there were no, zero, linked HIV transmissions within these couples. We think these findings really strongly support the hypothesis that condomless sex, when the viral load is undetectable, is a form of safe sex,” said Andrew Grulich, MBBS, PhD, from the University of New South Wales in Australia at a press conference briefing.

This is not the first study to demonstrate that people living with HIV who have undetectable viral loads do not transmit HIV to partners, although there have been fewer studies specific to men who have sex with men. A similar study, PARTNER, reported on the effectiveness of treatment as prevention among men who have sex with men in sites across 14 European countries in 2016. (PARTNER is ongoing until 2018.)

In addition to analyzing instances of condomless sex when partners had undetectable viral loads,  Opposites Attract also looked at instances when the HIV-positive partner had a viral load over 200 copies/mL. In this scenario, there were a relatively small number of condomless anal sex acts reported.

There were a total of 290 sex acts, over 5.2 person-years of follow-up, where the partner living with HIV had a detectable viral load and the HIV-negative partner was not on PrEP.  There were no HIV transmissions among these couples, which Grulich explained may be partly due to seropositioning. The HIV-negative partners in these instances were far more likely to be the insertive, rather than the receptive partner (which is an HIV-risk reduction strategy).

Although rates of sexually transmitted infections (STIs) were high in the study, there was no evidence that STIs increased risk for HIV transmission when HIV-positive partners were undetectable. Nearly a third of men living with HIV and a quarter of HIV-negative men were diagnosed with an STI during the study.

“Our results suggest that in the presence of undetectable viral load, those [rectal] STIs are no longer risk factors for transmission,” said Grulich. However, he added, “these biomedical responses don’t protect against STIs. In many settings, gay men will want to use condoms to protect themselves.”

Condoms can help protect against STIs in addition to HIV. Read more about the effectiveness of condoms on BETA.

Bruce Richman

Bruce Richman, founder of Prevention Access Campaign

Bruce Richman, the founder of the Undetectable = Untransmittable (U=U) campaign, was pleased to hear the results of the Opposites Attract study.

“We are thrilled to hear the Opposites Attract study adds even more data to the overwhelming body of clinical and empirical evidence to support U=U,” Richman told BETA. Richman launched the Undetectable = Untransmittable campaign about a year ago to raise awareness about treatment as prevention and decrease HIV-related stigma.

Find out more about the U=U message, and join the movement as a community partner. Find more information about the science behind treatment as prevention on BETA.


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