Treatment for Prevention
posted: 04/06/2010
"The strongest evidence to date" shows that HIV treatments can be used to prevent the passing on of HIV, reports the medical journal The Lancet. Treating HIV-positive heterosexual people in one recent African study reduced the risk of HIV transmission to their sexual partners by 92 percent. That is as good or better than condoms in cutting the risk of HIV transmission.
HIV transmission risks
More than 3,400 heterosexual couples, in which one partner had HIV and the other did not, in seven African countries (Botswana, Kenya, Rwanda, South Africa, Tanzania, Uganda and Zambia), were in the study.
"At the beginning of the study, the HIV-infected members had high CD4 counts and were not on antiretroviral treatment. Couples were provided with counselling and prevention services, followed for up to two years, with regular CD4 measurements and ART [Anti-Retroviral Therapy = HIV treatments] referrals made when they became eligible for ART".
After treatment of HIV positive partners: one infection
349 of the partners living with HIV in this study began taking HIV treatments. While 103 partners became HIV positive during the study, only one caught HIV after their partner with HIV started taking HIV treatments.
Deborah Donnell of the Vaccine and Infectious Disease Institute in Seattle, Washington state, USA, who was the study’s leading author, said HIV treatments cut the HIV Viral Load to low levels, making people far less infectious. 70% of the partners taking HIV treatments in this study saw their Viral Load fall to very low levels. A randomized trial has now begun to check this reduction in HIV transmission between partners continues.
"While awaiting those results, our study indicates that initiation of antiretroviral therapy may have a significant public health benefit as well as clinical advantages for the individuals being treated," Donnell said in a statement.
Test and Treat Prospects
This supports earlier research that suggested “the spread of HIV in hard-hit African nations could be cut by 95 percent in a decade, if all those infected started taking medicines immediately. That so-called test-and-treat theory has been disputed in other mathematical models that say those projections are based on flawed assumptions".
Warnings
The authors, like many clinicians, are worried that people with HIV will treat this news as permission to give up condoms. One of several critical requirements is avoiding sexually transmitted infections (STI). If either partner has an STI, that raises the risks of HIV being passed on. Many STIs show no symptoms. This study was of heterosexual couples – and HIV transmission risks for men who have sex with men are rather higher than for heterosexual couples.
"Although the 92% reduction in HIV-1 transmission that we report is highly encouraging, on an individual basis, counselling is needed to reinforce understanding that potential for HIV-1 transmission to partners remains after ART initiation," write the authors of the study. "This cohort received frequent counselling during 3-monthly follow-up, and we noted no evidence of behavioural risk disinhibition after ART initiation."
Test and Treat?
The authors conclude: "As countries strategise for optimum use of resources to expand ART provision beyond individuals with low CD4 cell counts, targeting of treatment to those with high plasma HIV-1 concentrations could be a cost-effective strategy to achieve maximum population-level reductions in HIV-1 transmission, as a step toward universal ART provision to all patients with HIV-1".
"We should not wait for the results of further models, observational studies, or the ongoing couple-based prevention trial before engaging in population-based trials of test-and-treat," the authors of a Lancet comment say. "Prevention of new infections would be the main goal but individual-level benefits can also be expected; to be evaluated against initially increased costs to the health-care system. Indeed, today's results argue powerfully for a new generation of research on HIV prevention at the population level with the best possible scientific methodology, including cluster-randomised trials".
Source
Other research
Lancet
Lancet editorial
University of Washington press release
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