Progress towards an HIV-1 subtype C vaccine

Several scientific fields related to vaccine development have made significant advances in understanding how to design immunogens against selected infectious pathogens. In the case of human immunodeficiency virus type-1 (HIV-1), anti-retroviral (ARV) drugs have dramatically improved the health and extended the lives of people with HIV/AIDS. However, their high cost of implementation and demanding clinical requirements put them out of reach of the vast majority of people with HIV, especially in developing countries where HIV infection levels are high and public resources are extremely scarce. With 25.4 million people living with HIV/AIDS in sub-Saharan Africa as of the end of 2004 (http://www.unaids.org), this region was still by far the worst-affected in the world with HIV-1 subtype C (HIV-1C) accounting for the majority of infections. Although the constraints placed by HIV genetic variation on vaccine efficacy remain unclear, there is an indication that they may be important and several candidate vaccines targeting HIV-1C are currently under investigation in both pre-clinical and clinical settings. The designs of these candidate HIV-1C vaccines focus on both regulatory and structural HIV-1 proteins derived from HIV-1C. They make use of a number of current vaccine technologies for their delivery to invoke adaptive immune responses in individuals that hopefully may prove to be protective. This review looks at the progress and accomplishments made thus far in the generation and testing of such HIV-1C vaccines.