B. Infantis Supplementation to Improve Immunity in Infants Exposed to HIV

The primary objectives of this study are to evaluate the effect of early-life B. infantis Rosell®-33 supplementation in infants exposed to HIV on: * gut microbiome composition and diversity at 4 weeks of life * markers of intestinal inflammation and microbial translocation at 4 weeks of life * Th1 cytokine responses to BCG at 7 weeks and 36 weeks of life The secondary objectives include to evaluate the effect of B. infantis Rosell®-33 supplementation on: * longitudinal succession of the gut microbiota composition, diversity and function * relative and absolute abundance of B. infantis in infant stool during the first 36 weeks of life * stool metabolome * T cell subset ontogeny during the first 9 months of life. Exploratory objectives are to evaluate whether B. infantis Rosell®-33 supplementation improves: * infant growth * all-cause morbidity * neurodevelopment during the first 9 months of life * antibody responses to early childhood vaccines

Infants who are born to mothers with HIV (exposed but uninfected; iHEU) are at higher risk of morbidity and display multiple immune alterations compared to infants who are HIV-unexposed (iHU). Easily implementable strategies to improve immunity of iHEU, and possibly subsequent health outcomes, are needed. iHEU have altered gut microbiome composition and bifidobacterial depletion, and relative abundance of Bifidobacterium infantis has been associated with immune ontogeny, including humoral and cellular vaccine responses. Therefore, a randomized trial of B. infantis Rosell®-33 versus placebo given during the first month of life in South African iHEU will be conducted. This is a parallel, randomised, controlled study. Two-hundred breastfed iHEU will be enrolled from the Khayelitsha Site B Midwife Obstetric Unit in Cape Town, South Africa and 1:1 randomised to receive 8 x109 CFU B. infantis Rosell®-33 daily or placebo for the first 4 weeks of life, starting on day 1-3 of life. Infants will be followed over 36 weeks with extensive collection of meta-data and samples.