The challenge of defining standards of prevention in HIV prevention trials.

As new HIV prevention tools are developed, researchers face a number of ethical and logistic questions about how and when to include novel HIV prevention strategies and tools in the standard prevention package of ongoing and future HIV prevention trials. Current Joint United Nations Programme on HIV/AIDS (UNAIDS)/World Health Organization (WHO) guidance recommends that participants in prevention trials receive 'access to all state of the art HIV risk reduction methods', and that decisions about adding new tools to the prevention package be made in consultation with 'all relevant stakeholders'. The guidance, however, leaves open questions of both process and implementation.