Potential vaccines raise ethical, logistical, and economic concerns.

Several years ago, central questions in the AIDS research field were: Is it possible to develop a vaccine against HIV? If so, when, and what strategies show the most promise? Now, even with no safe and effective vaccine in the pipeline, attention is nonetheless shifting towards potential problems associated with selecting the populations most in need of the product, conducting the clinical trials, and delivering the vaccine in a fair and equitable manner. These problems were the focus of a session at the annual meeting of the American Association for the Advancement of Science (AAAS), held in San Francisco in February. The following articles summarize two of the presentations at the session.