Epidemiology of clinical congenital and neonatal malaria in endemic settings: a systematic review and meta-analysis

In order to attain the objectives set out in the global technical strategy against malaria 2016–2030, it is important to have accurate epidemiological data on malaria in all age categories, including those which are often neglected because of an apparent low burden of disease. The current systematic review with meta-analysis synthesizes the epidemiology of clinical congenital and neonatal malaria in endemic areas.

PubMed, EMBASE, Global Index Medicus, and Web of Science were searched up to 30th October 2019, to identify observational studies reporting on congenital (0–7 days) and neonatal (0–28 days) malaria. No restriction related to language was applied. Study selection, data extraction, and methodological quality assessment were performed independently by two investigators. A random-effects meta-analysis was used to pool prevalence data. Prevalence were adjusted taking into account the variance due to diagnostic method and regional distribution. Subgroup analyses were performed to identify sources of heterogeneity in case of substantial heterogeneity. This review was registered in PROSPERO with number CRD42020150124.

The bibliographical search identified 1,961 studies, of which 22 were finally retained with a total population of 28,083 neonates. The overall crude prevalence of clinical congenital malaria was 40.4‰ (95%CI 19.6–67.7; 17 studies). The adjusted prevalence considering the variance due to difference in region/country (hierarchical model) was 33.7‰ (95%CI 6.9–77.2). There was no difference between the prevalence of clinical congenital malaria in Africa 39.5‰ (95%CI 17.2–59.5; 15 studies) and outside Africa 56.3‰ (95%CI 0.0–406.1), p = 0.867. The overall crude prevalence of clinical neonatal malaria was 12.0‰ (95%CI 1.4–30.3; 12 studies), and the adjusted one (considering the variance due to diagnostic method and the region/country) was 12.9‰ (95%CI 0.1–39.7). There was no difference between the prevalence of clinical neonatal malaria in Africa 12.1‰ (95%CI 1.3–31.2; 11 studies) and outside Africa 12.5‰ (95%CI 0.0–52.9), p = 0.802.

This study suggests a high prevalence of clinical congenital and neonatal malaria. It calls for an intensification of preventive measures against malaria during pregnancy and in the neonatal period, and to consider neonates as a distinct age category in the elaboration of malaria treatment and prevention guidelines.