Changing paradigms for an HIV vaccine.

More than ten years have passed since the discovery of HIV1,2, the virus which initiates the poorly understood cascade of events resulting in immunodeficiency and the clinical progression of AIDS. Enthusiasm for developing and testing prophylactic HIV vaccines has waxed and waned repeatedly in the intervening decade. Expectations of what the vaccine should do, and consequently how it should be designed, have evolved during that period. From the perspective of 1995, it is worthwhile to review that intellectual progression, take stock of current status of HIV vaccine development, and peer into the future of further development and possible actual human efficacy trials of candidate HIV vaccines.