Pathways Linking Socioeconomic Position and Malarial Infection and Healthcare-Seeking Behaviour for Suspected Malaria in Sub-Saharan Africa

Abstract

Malaria remains a leading cause of morbidity and mortality, with an estimated 249 million infections and 608,000 deaths recorded in 2022 alone. Over 94% of these cases and deaths occurred in sub-Saharan Africa (SSA). Despite progress in malaria prevention and control in SSA over the past two decades, socioeconomic disparities in malaria incidence and healthcare-seeking behaviour for febrile illnesses persist both at regional and national levels. This thesis is structured around three main components. First, a systematic review was conducted to examine the pathways linking poverty and malaria in SSA, focusing on studies that used mediation analysis, or reported changes in the coefficients of potential mediating variables in models adjusted for socioeconomic position (SEP) and mediators. The review appraised the mediation methods used and highlighted their strengths and limitations (Paper I). In Paper II, we used a regression-based counterfactual approach to mediation analysis in order to investigate the structural mechanisms driving socioeconomic disparities in P. falciparum infection, drawing on secondary data from two large cross-sectional studies conducted in the Southern region of Malawi during the dry and rainy seasons of 2014. This analysis presented the total natural direct effects (TNDEs) of SEP, the total natural indirect effects (TNIEs) through the mediator(s), and the proportion mediated (PM). In Paper III, we assessed the association between socioeconomic factors – SEP, maternal educational attainment and urban residence – and timely healthcare-seeking and diagnostic testing in children under five with febrile illness. A random-effects meta-analysis was conducted, using prevalence ratios (PRs) and standard errors from 16 nationally representative surveys conducted between 2018 and 2023. We also examined the mediating role of health facility type in the association between SEP and diagnostic testing. In the systematic review (Paper I), we identified mediators, such as improved food security, better housing quality, and previous antimalarial use, while factors such as secondary or higher education of maternal/household head, use of long-lasting insecticide treated nets (LLINs), better nutrition, and indoor residual spraying were suggested as potential protective mediators based on changes in coefficients. In paper II, using data from cross-sectional surveys conducted in Malawi, housing (TNIE, OR =0.54, 95%CI 0.49 – 0.63) and educational attainment of the household head (TNIE, OR = 0.73, 95%CI 0.67 – 0.81) were identified as mediators of the association between SEP and P. falciparum infection during the rainy season. During the dry season, housing (TNIE, OR = 0.63, 95%CI 0.59 – 0.64), educational attainment (TNIE, OR = 0.70, 95%CI 0.62 – 0.71) and LLIN use (TNIE, OR = 0.88, 95%CI 0.85 – 0.94) were important mediators. In Paper III, the results of the meta-analysis revealed that only 58.3% of febrile children received timely healthcare, and 38.2% underwent diagnostic testing. Higher SEP was associated with timely healthcare-seeking (PR = 1.18, 95%CI 1.11 – 1.25) and diagnostic testing (PR = 1.15, 95%CI 1.03 – 1.28). Higher maternal education was associated with timely healthcare-seeking in countries with malaria incidence ≥ 300 per 1,000 persons (PR = 1.11, 95%CI 1.01 – 1.23). Urban residence did not play a role in healthcare-seeking and diagnostic testing. The type of healthcare attended mediated the effect of SEP on diagnostic testing, with hospital visits (versus primary care) being associated with a higher likelihood of receiving diagnostic testing in 14 of 15 surveys. The findings presented clearly show that the socioeconomic situation of a population is significantly associated with malaria risk, with evidence on the mediating factors being particularly useful in guiding policy and programs on where to focus their efforts. Key priorities should include improving housing conditions, enhancing education or malaria prevention awareness and training, in combination with ensuring widespread distribution and correct use of LLINs to reduce malaria infection rates. Additionally, the socioeconomic inequalities in healthcare-seeking behaviours highlight the need for targeted efforts to mitigate barriers to healthcare access, such as providing subsidies to families with low SEP. Finally, improving diagnostic supplies and the quality of primary care services can significantly improve diagnostic testing and timely appropriate care for children with febrile illnesses.