Economic evaluations of human schistosomiasis interventions: a systematic review and identification of associated research needs

Abstract

Background: Schistosomiasis is one of the most prevalent neglected tropical diseases (NTDs) with an estimated 229 million people requiring preventive treatment worldwide. Recommendations for preventive chemotherapy strategies have been made by the World Health Organization (WHO) whereby the frequency of treatment is determined by the settings prevalence. Despite recent progress, many countries still need to scale up treatment and important questions remain regarding optimal control strategies. This paper presents a systematic review of the economic evaluations of human schistosomiasis interventions. Methods: A systematic review of the literature was conducted on 22nd August 2019 using the PubMed (MEDLINE) and ISI Web of Science electronic databases. The focus was economic evaluations of schistosomiasis interventions, such as cost-effectiveness and cost-benefit analyses. No date or language stipulations were applied to the searches. Results: We identified 53 relevant health economic analyses of schistosomiasis interventions. Most studies related to Schistosoma japonicum followed by S. haematobium. Several studies also included other NTDs. In Africa, most studies evaluated preventive chemotherapy, whereas in China they mostly evaluated programmes using a combination of interventions (such as chemotherapy, snail control and health education). There was wide variation in the methodology and epidemiological settings investigated. A range of effectiveness metrics were used by the different studies. Conclusions: Due to the variation across the identified studies, it was not possible to make definitive policy recommendations. Although, in general, the current WHO recommended preventive chemotherapy approach to control schistosomiasis was found to be cost-effective. This finding has important implications for policymakers, advocacy groups and potential funders. However, there are several important inconsistencies and research gaps (such as how the health benefits of interventions are quantified) that need to be addressed to identify the resources required to achieve schistosomiasis control and elimination.

Keywords: Cost per DALY averted; Cost-benefit; Cost-effectiveness; Economic evaluations; MDA; NTDs; Preventive chemotherapy; Schistosomiasis.

Figure 1.. Flow diagram outlining the inclusion and exclusion of the identified studies.

*Some studies reported both cost-benefit and cost-effectiveness estimates. A PRISMA checklist is supplied as extended data .

Figure 2.. Overview of the number of studies done and the investigated species.

LF: Lymphatic filariasis, STH: Soil-transmitted helminths.

Figure 3.. The observed cross-sectional host-age and mean infection intensity profiles for schistosome infections.

The data are from the following sources: Iietune village, Kenya , Matithini village, Kenya , Katheka village, Kenya , 12 villages in the Msambweni region of Coastal Kenya , and Luzon, Philippines . Note that these show the mean infection intensity for the entire sampled population (i.e. including both infected and non-infected individuals).