Worldwide, nearly 8.8 million children die each year before they reach their 5th birthday.1 More than two thirds die from infectious diseases such as pneumonia, diarrhoea, and malaria. Although these are sobering figures, childhood mortality has been substantially reduced over the past decade partly as a result of the expansion of child survival interventions to prevent and treat major causes of childhood mortality.

In the linked systematic review and meta-analysis (doi:10.1136/bmj.d5094), Mayo-Wilson and colleagues assess the effects of vitamin A supplementation on mortality and morbidity in children 6 months to 5 years of age.2 Routine preventive treatment of all children 6-59 months of age with high dose vitamin A supplements is a core intervention to improve child survival supported by Unicef, the World Health Organization, governments, and donors in areas of high mortality and endemic vitamin A deficiency. Capsules are now distributed biannually in at least 60 countries, with average annual coverage rates nearing 80%.3 Initially launched as an initiative to prevent xerophthalmic blindness, universal vitamin A supplementation was expanded as a life saving intervention mainly on the basis of meta-analyses that showed average reductions in …