An eight-year study of nearly 1,000 gay male couples — in which one partner was HIV positive and on suppressive antiretroviral therapy (ART) — found no HIV transmissions to the HIV negative partner.
Published in Lancet, 972 gay male serodifferent couples were followed over the course of eight years.
Some couples weren’t included in the final study because ‘no condomless sex was reported, they had used pre-exposure or post-exposure prophylaxis (PrEP or PEP), or HIV viral load or HIV test results were not available’.
How the study worked
The couples who participated in the study had to complete confidential questionnaires every 6-12 months. These questionnaires asked about their sexual behavior. During the check-ups, doctors tested the HIV negative partner and measure the HIV positive partner’s plasma HIV-1 viral load.
When the study began, most of the couples had been having condomless sex for a year. The average amount of time on ART for the HIV positive partner was four years.
Most of the HIV positive partners also had a high rate of adherence to ART. Only 5% reported missing ART for four or more consecutive days throughout the study.
Over a third of the HIV negative men said they had condomless sex with other partners. Another quarter of both HIV negative and positive men reported at least one STI such as syphilis and gonorrhoea since their last visit.
The authors noted one limitation of the study was that a majority of the HIV negative men were white. They also had an average age of 38 and a majority of transmissions are among younger men.
Over the course of the eight years, 15 HIV negative men received diagnoses. However, doctors linked none of these viruses genetically to the primary HIV positive partner in the study. The authors were then able to rule out within-couple transmissions.
‘Our findings provide conclusive evidence for gay men that the risk of HIV transmission with suppressive ART is zero,’ says Professor Alison Rodger from UCL, UK, who co-led the research.
She continued: ‘Our findings support the message of the international U=U campaign, that an undetectable viral load makes HIV untransmittable.
‘This powerful message can help end the HIV pandemic by preventing HIV transmission, and tackling the stigma and discrimination that many people with HIV face. Increased efforts must now focus on wider dissemination of this powerful message and ensuring that all HIV-positive people have access to testing, effective treatment, adherence support and linkage to care to help maintain an undetectable viral load.’