International research led by the National Institutes on Health ( NIH ) now has strong evidence that HIV treatment helps prevent transmission to sex partners.
This is the first time that gold-standard research—a randomized, controlled clinical trial—successfully demonstrates the concept of "treatment as prevention."
"Previous data about the potential value of antiretrovirals in making HIV-infected individuals less infectious to their sexual partners came largely from observational and epidemiological studies," said Anthony S. Fauci, M.D., director of the National Institutes of Allergy and Infectious Diseases ( NIAID ) , in a press release. "This new finding convincingly demonstrates that treating the infected individual—and doing so sooner rather than later—can have a major impact on reducing HIV transmission."
According to the release, "Men and women infected with HIV reduced the risk of transmitting the virus to their sexual partners by taking oral antiretroviral medicines when their immune systems were relatively healthy."
The study, HPTN 052, conducted by the U.S.-based HIV Prevention Trials Network, found a 96-percent drop in the risk of infection with the use of antiviral therapy. It looked at 1,763 couples from around the world in which one partner had HIV and the other one didn't. Half of the positive partners were put on anti-HIV therapy immediately. The other half received therapy when they experienced an AIDS-related event such as PCP ( pneumocystis pneumonia ) or a serious decrease in their immune-system function ( as evidenced by a drop in their CD4+ T-cell counts down to 250 ) .
The positive participants had moderately healthy immune systems when joining the study ( between 350 and 550 CD4+ T-cells ) , so they did not have advanced disease. The numbers of HIV-positive men and women in the trial were nearly equal.
HPTN 052 was designed to determine whether treating HIV-positive people with antivirals may protect their partners from HIV infection. It is also looking at the optimal time to start therapy in order to prevent illness and death.
The vast majority of the couples ( 97 percent ) were heterosexuals, and NIAID emphasized that "this precludes any definitive conclusions about effectiveness in men who have sex with men." The couples participated from 13 sites in Botswana, Brazil, India, Kenya, Malawi, South Africa, Thailand, the United States and Zimbabwe. They all received safer-sex counseling, free condoms, treatment for STIs ( sexually transmitted infections ) , regular HIV testing and evaluations and treatment of complications related to HIV.
Of 39 infections that occurred, 28 were genetically linked to the positive partner ( seven were not and four are still undergoing analysis ) .
Of these 28 infections, only one occurred in the treatment group of the study. This represented a 96-percent decrease in the risk of infection.
The findings were released early ( the study was scheduled to end in 2015 ) and, based on these results, all of the HIV-positive people in the deferred treatment group were offered antiretroviral therapy.
In early 2008, Swiss HIV experts published a consensus statement saying that HIV-positive people are nearly non-infectious if they are on effective antiretroviral therapy ( considered a viral load test result of less than 40 copies ) for at least six months and have no other STIs. The consensus was based in part on a relatively small study with heterosexual couples from Rakai, Uganda. There was limited data on reduced transmission via male-to-male sex. For more on the Swiss statement, see www.positivelyaware.com or www.aidsmap.org .
There is also research showing that some men who have undetectable HIV in their blood streams ( below the level of detection on a viral load test ) still have detectable levels of virus in their semen.
According to the website of the U.S. Centers for Disease Control and Prevention, the concept of HIV treatment as prevention is a promising avenue for lessening the risk of infection, but is not foolproof.
Courtesy of Positively Aware, from Test Positive Aware Network ( TPAN ) .
