Mitigating Infectious Morbidity and Growth Deficits in HIV Exposed Uninfected infanTs With Human Milk Oligosaccharides

Primary Objective: * To evaluate the effects of synbiotics on infectious morbidity and growth while it is in place from 4 to 24 weeks of age. * To evaluate the effects of synbiotics on infectious morbidity and growth from 4 to 48 weeks of age. Secondary Objectives: * To evaluate the effects of synbiotics on growth from 4 to 72 weeks of age. * To evaluate the effects of synbiotics on infant neurodevelopment at 48 and 72 weeks of age. * To evaluate the effects of synbiotics on biological measurements while it is in place from 4 to 24 weeks of age. * To evaluate the effects of synbiotics on biological measurements from 4 to 48 weeks of age. * To evaluate the effects of synbiotics on gut microbiome and fecal short chain fatty acids from 4 to 72 weeks of age. * To investigate feasibility, acceptance, tolerability, and behavioral adherence with the intervention. * To investigate whether the synbiotics reduces infectious morbidity and improves growth in CHEU relative to CHUU. * To investigate whether infant gut microbiota composition, maturity and function, and markers of inflammation and HMOs at baseline and over time are associated with morbidity and poor growth in CHEU and CHUU.