Exploring water, sanitation, and hygiene coverage targets for reaching and sustaining trachoma elimination: G-computation analysis.

• Published in: PLOS Neglected Tropical Diseases
• Main Authors: Kristin M Sullivan, Emma M Harding-Esch, Alexander P Keil, Matthew C Freeman, Wilfrid E Batcho, Amadou A Bio Issifou, Victor Bucumi, Assumpta L Bella, Emilienne Epee, Segni Bobo Barkesa, Fikre Seife Gebretsadik, Salimato Sanha, Khumbo M Kalua, Michael P Masika, Abdallahi O Minnih, Mariamo Abdala, Marília E Massangaie, Abdou Amza, Boubacar Kadri, Beido Nassirou, Caleb D Mpyet, Nicholas Olobio, Mouctar D Badiane, Balgesa E Elshafie, Gilbert Baayenda, George E Kabona, Oscar Kaitaba, Alistidia Simon, Tawfik Q Al-Khateeb, Consity Mwale, Ana Bakhtiari, Daniel Westreich, Anthony W Solomon, Emily W Gower
• Format: Article in Journal/Newspaper
• Language: English
• Published: Public Library of Science (PLoS) 2023
• Subjects: Arctic medicine. Tropical medicine; RC955-962; Public aspects of medicine; RA1-1270; Arctic
• Online Access: https://doi.org/10.1371/journal.pntd.0011103; https://doaj.org/article/394b5b5e3e7c4c2f83809c4f39640701

Background Trachoma is the leading infectious cause of blindness. To reduce transmission, water, sanitation, and hygiene (WaSH) improvements are promoted through a comprehensive public health strategy. Evidence supporting the role of WaSH in trachoma elimination is mixed and it remains unknown what WaSH coverages are needed to effectively reduce transmission. Methods/findings We used g-computation to estimate the impact on the prevalence of trachomatous inflammation-follicular among children aged 1-9 years (TF1-9) when hypothetical WaSH interventions raised the minimum coverages from 5% to 100% for "nearby" face-washing water (<30 minutes roundtrip collection time) and adult latrine use in an evaluation unit (EU). For each scenario, we estimated the generalized prevalence difference as the TF1-9 prevalence under the intervention scenarios minus the observed prevalence. Data from 574 cross-sectional surveys conducted in 16 African and Eastern Mediterranean countries were included. Surveys were conducted from 2015-2019 with support from the Global Trachoma Mapping Project and Tropical Data. When modeling interventions among EUs that had not yet met the TF1-9 elimination target, increasing nearby face-washing water and latrine use coverages above 30% was generally associated with consistent decreases in TF1-9. For nearby face-washing water, we estimated a ≥25% decrease in TF1-9 at 65% coverage, with a plateau upon reaching 85% coverage. For latrine use, the estimated decrease in TF1-9 accelerated from 80% coverage upward, with a ≥25% decrease in TF1-9 by 85% coverage. Among EUs that had previously met the elimination target, results were inconclusive. Conclusions Our results support Sustainable Development Goal 6 and provide insight into potential WaSH-related coverage targets for trachoma elimination. Targets can be tested in future trials to improve evidence-based WaSH guidance for trachoma.