Phase 1 Clinical Trials of the National Institutes of Health Vaccine Research Center HIV/AIDS Candidate Vaccines

(NIH) campus in Bethesda, Maryland. We are now close to reaching 10 years and are unlikely to realize an effective HIV/AIDS vaccine by 2007. Nevertheless, the NIH Vaccine Research Center (VRC), which opened in 2001, has become a force in vaccine research and development and, in this issue of the Journal, publishes a pair of articles [1, 2] reporting the results of phase 1 human trials for its HIV/AIDS vaccines, which are now well into phase 2 studies. The vaccine strategy uses DNA to prime the immune response and a replication-defective recombinant adenovirus serotype 5 (rAd5) vector to boost responses. All in all, the development of an HIV/ AIDS vaccine has been slow, hard work. Major problems have been the lack of immune correlates for protection, the extensive genetic diversity of the virus, and the inability to elicit neutralizing antibodies for incident isolates [3, 4]. Because of the problem in raising neutralizing antibodies, vaccine efforts have turned to eliciting T cells that, at least in preclinical nonhuman primate models, can protect CD4' T cells and control infections to the low levels