Vitamin A supplementation, infectious disease and child mortality: a summary of the evidence.

This manuscript reviews the evidence related to the effects of vitamin A (VA) supplementation of women and children on child health and mortality. VA supplementation of children aged 6-59 months has been well studied, and meta-analyses have consistently demonstrated effects on all-cause mortality, yet its mechanisms and the reasons for heterogeneous effects on mortality across trials continue to be debated. Recent meta-analysis of cause-specific mortality suggests beneficial effects on diarrheal mortality, with null but potentially beneficial effects also present for mortality from measles, lower respiratory infection, and meningitis. Some evidence suggests that pneumonia severity may increase with VA supplementation in this age group, particularly among well-nourished children. Maternal supplementation with VA during pregnancy has not shown benefits on neonatal mortality in large trials. A recent meta-analysis suggested that high-dose supplementation of lactating women immediately following delivery did not affect child survival. There is still uncertainty around the benefits of neonatal VA supplementation that should be resolved once the findings of ongoing trials are reported.