Our findings provide conclusive evidence that the risk of HIV transmission through anal sex when HIV viral load is suppressed is effectively zero. Among the 782 serodifferent gay couples followed for almost 1600 eligible couple-years of follow-up, which included more than 76,000 reports of condomless sex, we found zero cases of within-couple HIV transmission. In the absence of ART, on the basis of the frequency and type of sex, for receptive condomless anal sex acts alone approximately 472 transmissions (95% CI 83–714) would have been expected.
Rodger et al.
The Lancet recently published results of the largest study of HIV treatment as prevention among men who have sex with men, adding to the existing body of evidence that if people living with HIV take antiretroviral therapy (ART) as prescribed to achieve and maintain an undetectable viral load, there is virtually no risk of transmitting HIV to their HIV-negative partners. Read the full article.
The Study
The PARTNER2 study included nearly 800 mixed-status gay male couples in 14 countries in Europe between 2010 and 2017. In each couple, the partner living with HIV was on treatment and tested regularly to confirm a viral load of less than 200 copies/mL. The partner not living with HIV was tested regularly for HIV. The couples engaged in sex without condoms and without the partner not living with HIV using HIV pre-exposure prophylaxis (PrEP) or post-exposure prophylaxis (PEP).
The Results
There were no transmissions of HIV among the couples during the study period.
Why It’s Important
Earlier studies had provided strong evidence of the effect of antiretroviral therapy on the risk of HIV transmission between heterosexual mixed-status couples, but limited data was available on its effectiveness at preventing HIV transmission among men who have sex with men. The new results show that antiretroviral treatment with viral suppression prevents sexual transmission of HIV between gay male couples as well as it does among heterosexual couples.
Achieving Together Connection
Increasing viral suppression is one of Achieving Together’s Four Goals because it allows people living with HIV to have better health outcomes and live longer. This study adds to the evidence that people who can achieve and maintain a suppressed viral load (less than 200 copies per ml of blood) have effectively no risk of transmitting HIV. For people living with HIV this can remove the fear that many PLWH have about transmitting HIV to others.
