Vaccine Development

Education is the only means of HIV prevention currently available. Over the past few years significant efforts have been directed toward the development of an effective vaccine against HIV. Although substantial progress has been achieved, several obstacles still remain. Despite enormous advances in understanding the immunopathogenesis of HIV infection, the precise mechanism of protective immunity remains unknown.

Without such knowledge, it is difficult to develop vaccines that are assured of targeting the appropriate arm of the immune system that confers long-term protective immunity. Another obstacle is the lack of correlation of data from animal models to the potential protective effects of vaccines in humans. Therefore, even if an effective vaccine were available, it would take years of human testing to demonstrate its effectiveness.

Moreover, once a candidate vaccine is in human trials, the relatively low rate of HIV transmission and, in some cases, the difficulty in determining whether HIV infection has actually occurred will complicate the evaluation process.

Despite the enormous progress made in vaccine development over the last few years, it will take several more years before protective efficacy can be established. Even if an effective vaccine is established, education will remain the primary mode of HIV prevention, owing to the difficulty in knowing how long the protective immune effect will last.

Never before has so much been known about an epidemic during the time it was occurring. The challenge is to disseminate the knowledge to populations at risk in language they can understand and, ultimately, to modify activities so that the risk of transmission is minimized.