Global state of deworming coverage and inequity in low-income and middle-income countries: a spatiotemporal study of household health surveys

Abstract

IntroductionMass deworming against soil-transmitted helminthiasis (STH) is a hallmark program in the neglected tropical diseases portfolio that is designed to be equitable and \"pro-poor\". However, the extent to which current deworming treatment programs achieve equitable coverage across wealth class and gender remains unclear, and the current public health metric of national deworming coverage does not include representation of inequity. This study develops a framework to measure both coverage and equity in global deworming to guide future programmatic evaluation, investment, and metric design.\n\nMethodsWe used nationally representative, geospatial household survey data that measured mother-reported deworming receipt in pre-school age children (age 1-4 years) in the previous 6 months. We estimated global deworming coverage disaggregated by geography, wealth quintile and gender and computed an equity index. We examined trends in coverage and equity index across countries, within countries, and over time. We used a regression model to compute the household correlates of deworming receipt and ecological correlates of equitable deworming.\n\nFindingsOur study included 820,883 pre-school age children living in 50 STH-endemic countries between 2004 and 2017. Globally, the mean global deworming coverage in pre-school children was estimated at 36%. The sub-national coverage ranged from 0.5% to 87.5%, and within-country variation was greater than between-country variation in coverage. The equity index was undesirable (deworming was consistently concentrated in the wealthier populations) in every endemic region of 12 countries. Of the 31 study countries that WHO reported achieving the goal of 75% national coverage, 26 had persistent inequity in deworming as defined by the mean equity index. Deworming equity modestly improved over time, and within-country variation in inequity decreased over time. We did not detect differences in deworming equity by gender. We found the strongest household correlates of deworming to be vitamin A supplementation and receipt of three doses of diphtheria-tetanus-pertussis vaccine (DTP3), while the strongest ecological predictors of equitable deworming were regions with higher coverage of health services such as DTP3 and vitamin A supplementation.\n\nInterpretationAlthough mass deworming is considered to be \"pro-poor\", we find substantial inequities by wealth, despite often high reported national coverage. These inequities appear to be geographically heterogeneous, modestly improving over time, and we found no evidence of gender differences in inequity. Future reporting of deworming coverage should consider disaggregation by geography, wealth, and gender with incorporation of an equity index to complement national deworming coverage.\n\nFundingBill and Melinda Gates Foundation, Stanford University Medical Scientist Training Program