Ethics in preventive HIV vaccine research

It is widely acknowledged that the best hope of slowing the worldwide HIV epidemic lies in the development of a safe and effective preventive method. Yet, like any other research enterprise, the quest for an HIV vaccine requires adherence to ethical standards. Debates surrounding appropriate ethical standards for preventive vaccine research include, but are not limited to, the following questions. What should be provided to participants in vaccine trials who acquire HIV infection during the trial? Once an efficacious vaccine is approved by regulatory authorities and becomes available, is it acceptable to use a placebo for the control group in future vaccine trials? As other modes of prevention are found to be effective, should a prevention package be provided to all participants in HIV vaccine trials? What obligation exists to provide successful vaccine products to the community or country when trials have successful outcomes?