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Behavioral Mechanisms in Biomedical Strategies to Prevent HIV Infections

NAMHC Concept Clearance


Andrew D. Forsyth, Ph.D.
Chief, Primary HIV Prevention Program
Division of AIDS Research (DAR)


This initiative will advance understanding of the complex behaviors pertinent to the range of promising new biomedical strategies for averting HIV infections, including pre-exposure prophylaxis (PrEP), microbicides, male circumcision, and others.


The single most efficacious class of interventions shown to curb incident HIV infections thus far has been biomedical (e.g., preventing mother-to-child transmission, blood donor screening). Recent trials have shown that male circumcision is approximately 50 percent efficacious in preventing female-to-male transmission in Sub-Saharan Africa. Several other biomedical strategies are currently under investigation to determine their safety, efficacy, and cost-effectiveness (e.g., PrEP, microbicides, and HIV vaccines). Perhaps most salient among these are combination prevention strategies that attempt to improve early diagnosis of HIV infection, facilitate linkage to quality care, and reduce the risk of onward transmission.

However, the protection conferred by these and other biomedical strategies will likely depend upon a fundamental set of behavioral factors (e.g., acceptability, initiation and sustained use, risk compensation, and adherence to medications or risk reduction guidelines). Several studies have demonstrated that high levels of adherence are needed in order to avoid masking the true efficacy of promising biomedical strategies to prevent transmission. Still other strategies appear to be immune to these concerns, until one considers the potential for affecting perceived susceptibility to infection and post-trial behavior change at the community level.

Setbacks in these behavioral domains may effectively offset the benefits of promising new prevention technologies. At the same time, the public health impact of behavioral interventions may be enhanced considerably by pairing them with biomedical strategies that are offered in combination.

This initiative seeks to build new research in several scientific areas that include, but are not limited to, the following:

  • Address facilitators and barriers to uptake and durable adherence to HIV prevention strategies.
  • Elucidate behavioral decision-making under conditions of partial efficacy and uncertainty, and preventive misconceptions about the efficacy of experimental products or the benefits of participation in clinical trials.
  • Expand the battery of reliable and valid assessment tools to inform product acceptability, measure risk-taking, and gauge adherence to prescribed regimens and prevention guidelines.
  • Advance the design, testing, and modeling of combinations of partially efficacious, behavioral and biomedical interventions, which may tailored to fit specific subpopulation needs.
  • Conduct modeling studies to optimize the targeting of biomedical strategies and to estimate the epidemiological impacts of widespread implementation.
  • Conduct studies to guide decision-making among health care workers that improve the delivery of HIV testing and prevention services, as well as increase the receipt of test results.
  • Design modeling studies to help inform optimal resource allocation, as well as to determine levels of impact needed to drive down HIV infection rates.
  • Apply methodological and design innovations to discern the comparative effectiveness of key components of combination HIV prevention strategies.
  • Investigate new, effective strategies to facilitate linkage to care.
  • Study how to optimize the provision of brief, evidence-based counseling in resource-constrained settings that results in durable adherence to product and risk reduction guidelines.

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