PER 2/3/95 AMENDMENT: After the initial patients are enrolled, 18 additional newborns will be randomized to one of the three dose levels of rgp120/HIV-1MN (with no placebos). PER AMENDMENT 6/5/95: Another group of 18 newborns will be randomized to one of three treatments representing 3 different doses of the Chiron/Biocine vaccine (with no placebos).