Final Publication of PARTNER Results Reinforces U=U

The final results of the PARTNER study have been published in the journal The Lancet. The study reports that after 8 years of follow up, undetectable viral load on antiretroviral therapy results renders the individual unable to sexually transmit HIV.

The PARTNER2 study enrolled nearly 1000 gay male couples consisting of 1 HIV-negative partner and 1 partner confirmed to have HIV that was currently on ART and had a viral load <200 copies/mL.

PARTNER was an observational study that evaluated the risk of transmission risk when an individual was receiving ART. The first stage of the study took place from 2010-2014 and recruited and followed heterosexual and gay serodiscordant couples. The study investigators found that the results were less precise for the gay couples at the end of the study, and therefore, the second stage of the study, PARTER 2, aimed to produce similar results as observed in heterosexual couples.

PARTNER2 followed nearly 1000 gay male serodiscordant couple from 14 different countries in Europe from September 2010 to April 2018. To be eligible for enrollment, the HIV-positive member of the couple was required to be on ART at the point of enrollment. The couples were required to complete questionnaires every 6 months reporting the frequency of sexual activities. The investigators also monitoring the viral load of the HIV-positive partner and the HIV status of the HIV-negative partner every 6 to 12 months.

Over the nearly 8-year period, almost 70,000 episodes of condomless anal sex were reported, yet the results demonstrated 0 HIV transmissions within the couples in the study.

“PARTNER2 data provides robust evidence for gay men that the risk of HIV transmission with suppressive ART is zero,” Alison Rodger, MRCP FFPH MSc DipHIV MD, senior lecturer and honorary consultant for infectious diseases and the clinical director of public health at the University College of London, and lead author on the PARTNER study, said in a recent statement.

PARTNER2 demonstrated that ART is equally as effective for gay male couples as PARTER1 demonstrated for heterosexual couples, which is significant as anal sex is riskier than vaginal sex for HIV transmission.

“I think some of the most powerful data are the PARTNER 1 and 2 studies that really show how hard you can stress an undetectable person’s ability to transmit by having them have unprotected, condomless sex with their partner on repeated occasions with ejaculation and have no transmission. Both heterosexual and homosexual. And I think that’s really very powerful,” said W. David Hardy, MD, in a recent segment of Contagion®’s Peer Exchange on HIV Screening, Prevention, and Treatment Advances.

The Undetectable equals Untransmittable (U=U) campaign is working to change the public perception of HIV transmission, by reinforcing that if individuals who are HIV-positive take ART as prescribed, on a daily basis, and achieve an undetectable viral load, they will have effectively no risk of sexually transmitting the virus on to an HIV-negative partner. This discovery has significant implications for individuals who are living with HIV, especially those who are in serodiscordant relationships and are thinking about engaging in condomless intercourse or attempting to conceive a child.

Not only do these new results signify a similar level of confidence of the level of risk for gay couples is the same as heterosexual couples, the results further underscore the effectiveness of adhering to an ART regimen.