Transmission of HIV from an untreated infected mother to her offspring is thought to occur to some infants perinatally and others at parturition. It is possible that administration of an immunogenic vaccine can reduce the vertical transmission of HIV-1 or moderate its course in infected infants. Successful early sensitization to HIV epitopes might succeed in preventing HIV infection. Alternately, the enhancement of HIV-specific immune function might also succeed in modifying HIV replication and affecting disease progression.