[Development of HIV vaccines]

An effective prophylactic vaccine should reduce frequency of new HIV infections in the target population and delay onset of immunodeficiency among those who become infected after vaccination. A variety of vaccine candidates have been developed, which induce neutralizing antibodies and/or cytotoxic T-lymphocytes. While many of those vaccine candidates exhibited some efficacy in primate model systems, their efficacy against natural HIV-1 infection can only be determined in large-scale phase III clinical trials. In this article, difficulties in HIV vaccine development will be discussed from scientific, technical, and business point of views.