Effective antiretroviral therapy prevents detection of HIV in the blood, and thus transmission to an HIV-negative partner.
U = U for "undetectbal equals untransmittable". Understand "undetectable = untransmissible".
It is by this formula that for years, the associations of fight against the AIDS defends the principle according to which by suppressing the viral load of HIV, antiretroviral treatments prevent any transmission of the virus between sexual partners.
A new study, published this Friday in the British magazine The Lancet and "eight years of hindsight", confirms this conclusion. According to its authors, "the risk of HIV transmission among gay couples during sex without condoms when the viral load of HIV is suppressed is effectively zero". Already in 2016, the first phase of this research had reached the same conclusion.
Standard antiretroviral therapy involves combining at least 3 antiretroviral drugs (ARVs) to suppress HIV as much as possible by stopping the course of the disease. There has been a dramatic decline in mortality rates when using a strong antiretroviral regimen, especially in the early stages of infection.
472 cases of transmission prevented by treatment
This new work was carried out on 75 clinical sites in 14 European countries between September 2010 and July 2017. They covered 972 couples of men having unprotected sex and among whom at least one of the partners is HIV positive but whose viral load is undetectable with antiretrovirals.
Of these couples, 782 allowed researchers to study a total of "1,593 couple years". A meeting with participants was held every 4 to 6 months to find out how many of their reports were unprotected. In total, "76,000 anal sex without condoms" were identified.
At the end of the experiment, after 8 years of testing, the authors of the study found 15 new HIV infections. However, they could demonstrate by genetically analyzing the virus that they were not linked to transmissions within couples. On the contrary, they were able to show that the HIV transmission rate was zero in these male couples. According to the authors of this new work, antiretroviral treatment prevented 472 cases of transmission among couples who participated in the study.
A zero risk of transmission for gay and straight couples
"Our results provide conclusive evidence for gay men that the risk of HIV transmission with antiretroviral therapy that suppresses viral load is zero," says Alison Rodger, a professor at University College London and co-author of the study. study.
According to the researchers, this is the first study to study the risk of transmission among gay couples with one of the seronegative partners. It thus reinforces the idea that the risk of transmission in gay or heterosexual couples is "similar" in the case of anal and vaginal intercourse.
This new work is not free of limits. The researchers concede that the majority of HIV-positive participants had been taking antiretroviral therapy for several years, so they still have "limited data on the risk of transmission during the first few months of antiretroviral therapy."