A recent study of 358 serodiscordant male couples (that is, couples where one partner is HIV-positive and the other is HIV-negative) found that roughly 17,000 instances of condomless anal sex between the men resulted in zero cases of HIV.
PrEP and undetectability help prevent HIV transmissions
The researchers said that roughly 5,000 of the sexual encounters didn’t transmit HIV thanks to HIV-negative partners using pre-exposure prophylaxis (PrEP), a medication that can help reduce the chance of HIV transmission up to 99%.
The remaining 12,000 sexual encounters failed to transmit HIV because the HIV-positive partners were undetectable, that is, taking medications that reduce the amount of HIV in the blood to levels so low that the virus can’t be detected by an HIV test. When one is undetectable, it’s virtually impossible to transmit the virus.
The study, called the Opposites Attract study, was led by professor Andrew Grulich from the Kirby Institute, a medical research organization affiliated with the University of New South Wales that studies infection and immunity in society.
Grulich and his researchers followed 358 gay male couples in Australia, Brazil and Thailand, following each individual couple for about 1.5 years. The overall study took about 4 years to complete.
Grulich recently presented his team’s research at the International Aids Society Conference on HIV Science in Paris, France.
What does the study prove?
Grulich told Buzzfeed News that the research “really does confirm that undetectable viral load is completely effective at preventing transmissions in gay couples. Essentially, we’re documenting that this is a form of safe sex for couples in this situation.” He also called the discovery “transformative” for serodiscordant male couples.
“This tells us that if an HIV-positive person gets on treatment, achieves undetectable viral load – and that can take three-to-six months, it’s not immediate – they will not transmit, provided they continue to take their pills daily and see their doctor to have their viral loads monitored.”
According to Buzzfeed News, the Opposites Attract study is the largest study on HIV transmission between serodiscordant gay couples ever, and “is the first to consider data from both high-income and middle-income countries.”
Featured image by Louis-Paul St-Onge via iStock