It has been reported that 5.4 million new HIV infections occur each year, 10% of which are in children and 50% in females. Over 90% of infections occur in the developing world where highly active antiretroviral therapy is unlikely to be readily available. Therefore, the need for a prophylactic vaccine for HIV is compelling. All sessions of 'AIDS Vaccine 2001' were valuable, but this report mainly considers two slide sessions where new candidate vaccines and vaccine strategies were discussed. It is of major importance that as many novel vaccine strategies as possible are explored, and that meaningful comparisons are made between the responses they induce. Even a vaccine that does not offer full sterilizing immunity to HIV infection could have a dramatic effect on the pathogenesis of HIV disease and on transmission of HIV from person to person.