Assessment of the sustained use of insecticide-treated bednets on all-cause child mortality in an area of intense perennial malaria transmission in western Kenya
Description
The use of insecticide-treated bednets (ITNs) has proven to be a promising and affordable intervention for controlling malaria in endemic areas of sub-Saharan Africa. However, there is concern that sustained ITN use in areas of high malaria transmission may delay the acquisition of clinical malaria immunity, consequently shifting the burden of mortality from younger to older children. Furthermore, there is concern that the efficacy of ITNs may diminish following sustained use due to the potential of lowered malaria immunity among the target population. To address these concerns, monitoring of child mortality using a demographic surveillance system (DSS) was continued for an additional two years after ITNs were distributed to control villages at the completion of a two-year community randomized control trial that assessed the impact of ITNs in an area of intense perennial malaria transmission in western Kenya. Consequently, all-cause child mortality (1--59 months) was assessed among children living in villages where ITN coverage has been sustained for over four years, as well as within villages where ITNs had only recently been introduced within the past two years. An additional aim of this research was to provide an evaluation of the DSS at identifying births and death in children <5 years old using a two-sample capture-recapture method. Results from this research provide no evidence of a shift in mortality from younger to older children following sustained ITN coverage in this setting. ITNs were associated with saving approximately 355 post-neonatal infants and 468 children 1--59 months over the course of the four-year trial. Additionally, ITNs were shown to remain efficacious at reducing all-cause post-neonatal infant mortality, and to a lesser extent 1--59 month mortality, over the entire course of the trial. And lastly, capture-recapture methods appear to be a worthwhile tool for assessing differential ascertainment of vital demographic events between subgroups of the population monitored with a DSS