A safe, effective, and affordable vaccine remains the best long-term hope for bringing the global human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic under control. Recent scientific developments have suggested that the first generation of HIV vaccines available for public health care use will likely be of low to moderate efficacy, compared with currently licensed vaccines for other diseases. Nevertheless, such "partially effective" HIV vaccines could provide considerable individual and public health benefits. A consultation was held in January 2002 to advise the Centers for Disease Control and Prevention (Atlanta, Georgia) about critical issues that need to be addressed in anticipation of the eventual licensure and availability of an HIV vaccine in the United States. The present article summarizes the major issues discussed at the consultation with regard to the potential use of a partially effective vaccine in HIV prevention programs in the United States and the activities that are needed to prepare for vaccine availability.