Time to Take Stock in HIV/AIDS Prevention

Abstract

The first behavioral interventions designed to stem the spread of HIV were tested over 25 years ago, within just a few years of the first reported cases of AIDS. Interventions grounded in sound theories of behavior change have since been demonstrated effective at reducing high-risk injection and sexual practices in nearly every population with known risks for HIV/AIDS. Brief risk reduction counseling, small group skills building workshops, syringe exchange programs, enhanced HIV counseling and testing, interventions aimed at people living with HIV/AIDS, condom social marketing programs, peer influence models and other behavioral HIV prevention approaches have all shown efficacy in carefully controlled clinical and community trials. Meta-analyses repeatedly show that these interventions produce consistent positive behavioral outcomes and several have significantly reduced recurrent sexually transmitted infections. Unfortunately, behavioral interventions have also demanded considerable commitment to implement and resources to sustain. Despite their effectiveness, HIV risk reduction interventions have not provided the quick fix to the AIDS problem that so many policy and decision makers have sought for the past 20 years. In contrast to behavioral interventions, biomedical approaches to HIV prevention offer the promise of immunity, permanent reductions in susceptibility, and diminished infectiousness. By far, the most successful biomedical intervention for HIV prevention remains the use of antiretroviral medications for preventing mother-to-child transmission of HIV. Comprehensive mother-to-child transmission prevention programs have witnessed declines in HIV infected infants to levels approaching zero. For example, in New York there were nearly 100 HIV infected infants in 1997 whereas there were less than 10 in 2006. The number of HIV infected babies has similarly plummeted in Botswana where all pregnant women are tested and treated, whereas neighboring South Africa has been slow to implement mother-to-child prevention of HIV transmission and the country remains burdened by these avoidable and tragic infections. Several important clinical trials that are testing new biomedical HIV prevention interventions were launched in the early part of this decade and their results are now becoming available. Most encouraging has been the definitive findings from three randomized clinical trials of male circumcision for HIV risk reduction (Auvert et al. 2005; Bailey et al. 2007; Gray et al. 2007). These compelling studies all showed as much as a 60% reduction in HIV transmission among men who underwent circumcision, a magnitude of protection that cannot even be expected from most vaccine models. Male circumcision faces implementation challenges due to obvious cultural and religious meanings attached to circumcision, issues that individual communities have to sort out. But the effectiveness of male circumcision for preventing female-to-male HIV transmission is indisputable. The results of several other eagerly awaited biomedical prevention technologies have unfortunately been more disappointing. Based on a clear and convincing model of cervical susceptibility to HIV transmission, Nancy Padian conducted a critical study of the diaphragm for HIV prevention. The findings did not demonstrate added benefit from diaphragm use over and above supplying women with condoms and risk reduction counseling (Padian et al. 2007). In the past year we have also seen two promising vaginal microbicides, cellulose sulfate and Carraguard, fail to demonstrate efficacy. What was another innovative approach to preventing HIV transmission was use of antiviral medication to suppress Herpes Simplex Virus (HSV) S. C. Kalichman (&) University of Connecticut, Storrs, CT, USA e-mail: seth.k@uconn.edu