Background:  The scientific obstacles that confront development of an effective HIV-1 vaccine are formidable.

Conclusions:  These obstacles will be summarized, and a series of questions will be posed and addressed:  Is an effective HIV-1 vaccine feasible at the current time? Should we be surprised by the failure of the Merck recombinant adenovirus product to demonstrate efficacy? Do any of the products currently in the pipeline hold any reasonable promise for efficacy? Is there potential for negative ramifications following repeated efficacy trial failures? Do we have the right balance of discovery research versus product development, product manufacturing and clinical testing?