STUDY: Zero HIV Transmissions When Undetectable on Treatment

A groundbreaking study on antiretroviral treatment showed that the drugs can disable HIV and stop sexual transmission. The randomized study of 1,700 couples was conducted by UNC-Chapel Hill and confirmed a 2011 study that stated ART could prevent transmission of HIV if it is taken reliably. The medications suppress HIV and can render it virtually harmless, unable to transmit to a sexual partner. 

The catch though, is patients must stay adhere to treatment, as going off ART will cause the virus to reemerge. In the U.S., there are 1.2 million people living with HIV but only 37 percent of them are on ART.

"If people are taking their pills reliably and they're taking them for some period of time, the probability of transmission in this study is actually zero," Myron Cohen, chief of the Institute of Global Health and Infectous Diseases at UNC to The News and Observer. "Let me say it another way: We never saw a case of HIV transmission in a person who is stably suppressed on ART."

Cohen announced the findings at the International AIDS Society Conference in Vancouver. 

While the news from this and the 2011 study confirm that HIV viral loads can be suppressed to a level where it cannot be transmitted, Cohen cautioned that ART is not a proxy for a vaccine. It can however, break the chain of transmission, he told the News and Observer. 

In addition, Cohen said, researchers were still unclear as to how long a person remains contagious after starting treatment. In four cases of the over 1,700 mostly heterosexual couples in nine countries studied from 2005 to 2010 a sex partner was infected shortly after treatment began, but researchers concluded in those cases that the virus had not been suppressed yet.