Progression from uncomplicated to severe malaria among children in settings receiving different combinations of malaria control interventions in sub-Saharan Africa: a systematic review and meta-analysis.

BACKGROUND

There is a high variability in the pattern of deployment of combinations of malaria vectors and parasite control interventions across sub-Saharan Africa. Effects of such deployment on disease progression from uncomplicated to severe malaria (a proxy measure of naturally acquired immunity against clinical malaria) is unknown. This systematic review and meta-analysis determined the prevalence of progression from uncomplicated to severe malaria, prevalence of parasitaemia and prevalence of gametocytemia among children in settings receiving different combinations of malaria control interventions in sub-Saharan Africa.

METHODS

The protocol for this review was registered by the International Prospective Register for Systematic Review (PROSPERO) with registration number CRD 42024619945. The review followed the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. We comprehensively searched relevant articles published in PubMed, Embase, Web of Science, Scopus and Google Scholar from 1st January 2000 to 31st December 2024. Title, abstract and full text screening were done by inserting relevant search terms and Boolean operators in the search engines of the databases. Bibliography searches of referenced literature were also done. Risk of Bias analysis was done using modified Newcastle-Ottawa tool. Random effects model, Odds ratio and pooled 95% confidence interval in STATA ver 17.0 were used to perform bivariate meta-analysis and sub-group analysis.

RESULTS

Twelve studies involving 9,283,160 individuals were included in this review. There was no significant difference in the odds of progression from uncomplicated to severe malaria in settings receiving different combinations of malaria control interventions (OR:0.56; 95%CI 0.31 to 1.02P = 0.06). Simultaneous deployment of more combinations of malaria control interventions were associated with significantly lower odds of severe malaria(pooled OR = 0.41; 95%CI0.30,to 0.56; p < 0.00), lower odds of parasitaemia (pooled OR = 0.52; 95%CI0.38 to 0.70; p < 0.00), lower odds of uncomplicated malaria (pooled OR = 0.64; 95% CI0.43 to 0.95; p = 0.003) and a lower odds of gametocytes (pooled OR = 0.41; 95% CI 0.28 to 0.60; p < 0.00). There is no significant difference in the odds of severe malaria between settings with single versus those with no interventions (pooled OR = 0.35; 95%CI 0.11 to 1.13). Selected articles exhibited high heterogeneity.

CONCLUSION

In comparison to single or no intervention, combination of multiple malaria control interventions significantly protects against severe malaria, parasitaemia, gametocytes and uncomplicated malaria. In comparison to single or no interventions, deployment of multiple combinations of control interventions did not offer additional protection against progression from uncomplicated to severe malaria.