Should we prioritise children 6-23 months of age for vitamin A supplementation? Case study of West and Central Africa.

Background: Vitamin A (VA) supplementation has been associated with reductions of all-cause child mortality. Child mortality amenable to VA, particularly related to infectious diseases, may be age dependent; hence, the beneficial effect of VA supplementation may differ between younger and older children. We aimed to estimate the all-cause child mortality disaggregated by younger and older than 2 years of age and estimate the contribution of VA supplementation in preventing child death in West and Central Africa. Methods: Using the most recent (post-2010) cross-sectional Demographic and Health Surveys and Multiple Indicator Cluster Surveys, we analysed child-level data (n=187 651) from 20 West and Central African countries. Age-specific (all-cause) mortality rates were estimated using survival analyses. Age-specific VA supplementation coverage was linked with the age-specific all-cause child mortality to estimate the contribution of the supplementation in averting child death. Results: The cost per averted child death was also estimated using an average cost of US$1.2/child and VA supplementation coverage which ranged from 14% in Cote d'Ivoire to 81% in the Gambia. About 75% of the under-5 mortality occurred in the first 2 years of life. The share of excess (all-cause) mortality averted by VA supplementation was significantly higher in the first 2 years of life. A mean reduction of 7.1 deaths/1000 live births was estimated for children 6-23 months, compared to a reduction of 2.5 deaths/1000 live births for older children (24-59 months). The mean cost/averted child death for the 20 countries was 2.8 times lower for the 6-23 than the 24-59 months age group. Conclusion: Prioritising VA supplementation for children in the first 2 years of life could be more cost-effective than when implemented among 6-59 months of age.