Kelly MS, et al. - Researchers conducted a hospital-based prospective cohort study investigating mediators of the poor pneumonia outcomes of human immunodeficiency virus–exposed but uninfected children. They recognized worse pneumonia outcomes among Human immunodeficiency virus–exposed but uninfected (HIV-EU) children than HIV-unexposed children. In this study, nonbreastfeeding mediated nearly half of the effect of HIV exposure on pneumonia mortality. Findings provided further support for a mortality benefit of breastfeeding by HIV-EU children.