amfAR, The Foundation for AIDS Research

Study Affirms Preventive Effect of HIV Treatment

Partially funded by amfAR, study shows that effectively treated HIV blocks transmission in couples of differing HIV status

One of the biggest worries KirbyProfessor Andrew Grulich presenting his poster on the Opposites Attract study at the 2015 Conference on Retroviruses and Opportunistic Infections (CROI). (Source: Kirby Institute)of people living with HIV is that they will infect their partner. But a recent study essentially puts those fears to rest for those on effective treatment.

The largest study to date of HIV transmission risk in gay male couples of differing HIV status (one is HIV positive and the other is negative) has shown that HIV-positive men whose viral load is undetectable do not transmit HIV to their partners. The results of the study, called Opposites Attract, were reported at the IAS Conference on HIV Science in Paris, July 25.

"Undetectable virus level effectively prevents HIV transmission among gay couples," said Chief Investigator Professor Andrew Grulich from the Kirby Institute in Sydney, Australia. "Opposites Attract is the first study to show that these results apply in both high and middle income countries."

Opposites Attract followed a cohort of 358 gay couples of differing HIV status in Thailand, Brazil and Australia from 2012 to 2016.

"Our data add to previous studies which show that there has never been a recorded case of HIV transmission from an HIV-positive person to their HIV-negative sexual partner when the HIV-positive partner had undetectable viral load," said Dr. Grulich. "Our research adds to the evidence from a small number of other international studies of heterosexual and homosexual couples and means that we can say, with confidence, that effectively treated HIV blocks transmission in couples of differing HIV status."

Opp Attract photo.KIRBYSource: Kirby Institute In addition to the Kirby Institute, investigators were from the Evandro Chagas Clinical Research Institute, Fiocruz in Brazil and the Thai Red Cross in Thailand. The study was primarily funded by the National Health and Medical Research Council (NHMRC). A two year extension was made possible by amfAR, Viiv, and Gilead.

"As HIV continues to disproportionately affect gay men and other men who have sex with men worldwide, the results of this study are extremely encouraging and underscore the need to get people tested and onto treatment immediately if they are HIV positive," said amfAR Chief Executive Officer Kevin Robert Frost. "This important breakthrough underscores yet again how investments in HIV research yield invaluable dividends in the global response to HIV."

Click here for the press release from The Kirby Institute.