HIV vaccine efficacy trials: A brief history, and options for going forward.

HIV vaccine research has recently produced a number of efficacy results, in addition to some promising preclinical developments. Some of these have been surprising, leading to parallel calls for a better understanding of HIV pathogenesis and immunity, while accelerating the number of candidates that can be tested empirically in clinical trials. In this review, we describe the development of three HIV vaccine efficacy trials to date, and highlight some of the possible avenues available for the field of biomedical HIV prevention to proceed.