Effectiveness and Implementation Challenges of Malaria Control Interventions Among Children Under Five in Malawi: A Systematic Review

Abstract

Background: Malaria remains a major cause of morbidity and mortality among children under five years of age in Malawi despite the widespread implementation of insecticide-treated nets (ITNs), indoor residual spraying (IRS), and the RTS,S/AS01 malaria vaccine. However, evidence regarding the effectiveness of these interventions remains fragmented.

Methods: A systematic review was conducted following the PRISMA 2020 guidelines. PubMed, Scopus, Web of Science, and Embase were searched for studies published between 2015 and 2025 evaluating malaria control interventions among children under five years of age in Malawi. Eight studies met the inclusion criteria and were synthesised narratively due to heterogeneity in study designs and outcome measures. Methodological quality was assessed using study-design-appropriate appraisal tools, including CASP checklists for empirical studies. Five studies were assessed as high quality and three as moderate quality.

Results: Across the included studies, ITN use was generally associated with lower malaria risk or prevalence, although the magnitude of effect varied due to differences in study design, outcome measures, and study settings. IRS reduced prevalence by up to 20% in sprayed households. Evidence on RTS,S/AS01 indicated protection against clinical malaria that varied with environmental context, while modelling estimated the greatest reductions (65–71%) when vaccination was combined with ITN use. Post-introduction evidence identified no new vaccine safety concerns. Intervention effectiveness was influenced by utilisation, coverage, insecticide resistance, environmental conditions, and socioeconomic factors. Key implementation challenges included inconsistent ITN use, logistical constraints, and inequities in access and uptake.

Conclusions: Malaria control interventions were generally associated with reductions in the malaria burden among children under five years of age in Malawi, with modelling evidence suggesting additional benefits from combining RTS,S/AS01 vaccination with ITN use. However, evidence on combined interventions was limited and heterogeneous, with the largest estimated benefits derived from modelling. Strengthening integrated delivery strategies, improving adherence, and addressing implementation challenges are essential for achieving sustained reductions in malaria transmission.