Although community randomized trials have found a reduction in all-cause child mortality in communities receiving mass azithromycin distribution compared with placebo, individually randomized trials have not found similar protective effects. If a direct effect of azithromycin for prevention of child mortality exists, it is likely due to reduction in infectious mortality. Here, we assessed cause-specific mortality in a large randomized controlled trial of azithromycin administered during well-infant visits in Burkina Faso for prevention of mortality. Among 32,877 enrolled infants, the most common causes of death by 6 months of age were malaria, acute respiratory infections, and diarrheal disease. We found no evidence of a difference in the distribution of cause of death by randomized treatment assignment (P = 0.42) or in any infectious-specific cause of death. The results of this analysis are consistent with no direct effect of azithromycin on infant mortality when administered during well-infant visits.

Single-dose azithromycin is being considered by the WHO as an intervention for prevention of child mortality. However, concerns have emerged related to longer term unintended consequences of early life antibiotic use, particularly among infants. We conducted a long-term follow-up in a random sample of children who had been enrolled in a trial of neonatal azithromycin versus placebo for prevention of mortality to assess whether neonatal azithromycin exposure led to differences in child growth up to 4 years of age. We found no evidence of a difference in any anthropometric outcome among children who had received a single oral dose of azithromycin compared with placebo during the neonatal period. These results do not support long-term growth-promoting or deleterious effects of early life azithromycin exposure.