Safety & Immunogenicity of 426c.Mod.Core-C4b Vaccine With 3M-052-AF+Alum in Infants Perinatally Exposed to HIV But Uninfected

Inclusion Criteria: Mother * Mother's age is at least 18 years and is willing and able to provide written informed consent for their and their infant's participation in this study * Mother is in the second or third trimester of singleton pregnancy, as determined by a clinical exam or sonography and reported menstrual history * Mother agrees to donate umbilical cord blood * Mother has a planned Caesarian delivery at Chris Hani Baragwanath Academic Hospital (Soweto) and plans to remain in the area after delivery and through study duration * Mother is determined by the site investigator to be in good overall health at the time of delivery based on medical history and physical exam * Mother has a documented CD4 count of more than 350 cells/mcL at screening * Mother has been on cART for at least 16 weeks prior to delivery and intends to continue with cART for the duration of breastfeeding * Mother has a viral load of less than 400 copies/mL between 2 weeks before and 7 days after delivery * Mother has access to the participating HVTN CRS and is willing to be followed for the planned duration of the study * Mother demonstrates understanding of this study and is able and willing to complete the informed consent process and delivery with verbal demonstration of understanding of all questionnaire items answered incorrectly * Mother agrees not to enroll either self or infant in another research study for the duration of the trial without prior approval of the HVTN 316 PSRT. * Mother h…