Preventing HIV transmission with antiretrovirals

The final results of the PARTNER study are now published in the leading medical journal The Lancet. The study reports zero HIV transmissions over eight years in gay men not using condoms, finally confirming that an undetectable viral load on HIV treatment renders an individual sexually non-infectious.

Almost 1000 gay male couples contributed to the PARTNER2 study. One partner was HIV negative and the other was HIV positive and on effective HIV treatment with viral load less than 200 copies/mL.

With up to eight years follow up and approximately 77,000 times that couples had sex without using condoms, the PARTNER 2 study reported that there were no HIV transmissions within the couples in the study. The results showed that antiretroviral treatment (ART) is just as effective for gay couples as an earlier phase of the study proved it was for heterosexual couples. This is important because without a positive partner being on treatment anal sex is at higher risk for HIV transmission compared to vaginal sex.

The study, led by University College London and the University of Copenhagen, has involved 75 centres in 14 European countries, including the Fight AIDS Foundation, IrsiCaixa and BCN Checkpoint, and provides robust evidence for gay men that the risk of HIV transmission with suppressive antiretroviral treatment is zero.

The results support the international U=U campaign to highlight and campaign for greater awareness of how effective ART can help people have sex without any fear of passing HIV on. In 2016, partly because of the results of the PARTNER-1 study, the Prevention Access Campaign launched the U=U (undetectable equals untransmittable) campaign. This campaign is based on the statement that a person living with HIV who has undetectable viral load does not transmit HIV to their partners and is supported by leading HIV medical organisations and more than 850 HIV community organisations in almost 100 countries.

The final publication of the results, which were first presented at the AIDS2018 conference in Amsterdam in July 2018, finally provides and acknowledges the scientific evidence for how effectively HIV treatment prevents sexual transmission. The results are important to support improving the quality of life for HIV positive people and their partners globally.