Failure of the Merck HIV vaccine: an uncertain step forward.

摘要

An HIV vaccine remains the primary goal for a comprehensive strategy to curb the global HIV epidemic. Yet the path to success is unknown and, on the basis of two reports from the Step Study in today's Lancet,12 seems to have become more complicated.In the randomised Step Study, Susan Buchbinder and colleagues assessed the efficacy of the Merck HIV vaccine to prevent infection or reduce early viral burden though the induction of T-cell immunity alone. This vaccine uses a recombinant replication-incompetent adenovirus type 5 (Ad5) that expresses the relatively well-conserved HIV gag, pol, and nef genes from subtype B strains of HIV. The results show the vaccine failed to achieve either objective, and suggest an increase of HIV infection rate in male participants on the vaccine (4-6%) compared with controls (3-1%, p=0-07).