HIV vaccine development.

Optimism prevails that a safe and at least partially effective HIV vaccine will be identified within this decade. Public, philanthropic and private sector efforts to expand the development pipeline and to include candidates based on diverse HIV subtypes have proved successful. Yet both scientific and logistical obstacles remain. No vaccine candidate yet induces broadly neutralizing antibodies. The type, level, location and durability of immune responses necessary for protection remain unknown. For those vaccines that may not prevent HIV infection but control replication and prevent disease, the issue of transmissibility must be addressed. Other challenges include improving infrastructure and research capabilities and establishing or strengthening regulatory agencies in developing countries. Another key issue is ensuring access to successful vaccines, which will require large-scale manufacturing and development of policies and processes to distribute vaccine to those most in need.