In parallel to these efforts, genetic studies at the population level could provide critical information on the most promising paths to follow. In particular, the recent completion of the International HapMap Project now permits whole genome associated studies to be conducted with a minimum number of single nucleotide polymorphism tags [55, 56] . This powerful new technology could be used to identify genes that are associated with the wide variation in neutralizing antibody responses in HIV-1-infected individuals and in vaccine recipients. A critical question to ask is whether the potent neutralizing antibody response in a small subset of infected individuals is due to unique viral epitopes or to host genetic polymorphisms. Current evidence suggests that both might make a substantial contribution in the context of combined epitope and allelic representations [28, 47, 57] .