There is inconclusive evidence that antibiotic prophylaxis in certain groups of high-risk children can reduce pneumonia, exacerbations, hospital admission and mortality in certain conditions. However, limitations in the evidence base mean more clinical trials assessing the effectiveness of antibiotics for preventing LRTIs in children at high risk should be conducted. Specifically, clinical trials assessing the effectiveness of antibiotics for preventing LRTIs in congenital heart disease, metabolic disease, endocrine and renal disorders, neurological disease or prematurity should be a priority.