Estimating cases of severe malaria: Analysis of household surveys in 19 malaria endemic countries in Africa

Abstract Background The burden of severe malaria is uncertain at the population level because existing estimates rely heavily on data from the formal healthcare system. Using data from population-based surveys, this analysis examines severe malaria cases at the population level, which captures malaria positive children whose caregivers 1) have taken the child to a healthcare facility but the child’s illness did not resolve, or 2) have not sought care for the child’s illness. Direct inclusion of these children in severe malaria estimates has been an underlying data gap. Methods This analysis examined data from 37 Demographic and Health Surveys and Malaria Indicator Surveys across 19 countries in sub-Saharan Africa collected between 2011 and 2018. The outcome of interest is a proxy indicator for severe malaria, defined as children age 6-59 months who were positive for malaria with at least one self-reported symptom of severe illness including loss of consciousness, rapid breathing, seizures, or severe anemia (hemoglobin <5 g/dl). The study includes a weighted descriptive, country-level analysis and a multilevel mixed-effects logistic regression model to assess the determinants of severe malaria. Results Among children positive for malaria across all surveys, 4.5% (95% CI 4.1–4.8) had at least one sign or symptom of severe malaria, which was significantly associated with age, residence, wealth, and fieldwork year at a p-value less than 0.05. Malaria positive children in the higher malaria transmission zone were more likely to have signs or symptoms of severe malaria compared to those in the lowest transmission zone; however, these results were not statistically significant. Conclusion Having an accurate estimate of severe malaria cases among malaria positive children is essential to assessing the impact of malaria interventions and to guiding future malaria investments. This analysis presents a novel approach of estimating severe malaria cases among malaria positive children under age five in malaria endemic countries. Estimating severe malaria cases through household-based surveys allows countries to estimate severe malaria across time and to compare with other countries. Having a population level estimate of severe malaria cases helps further our understanding of the burden and epidemiology of severe malaria.