Long-term impacts of an urban sanitation intervention on enteric pathogens in children in Maputo city, Mozambique: study protocol for a cross-sectional follow-up to the Maputo Sanitation (MapSan) trial five years post-intervention

Introduction We previously assessed the effect of an onsite sanitation intervention in informal neighborhoods of urban Maputo, Mozambique on enteric pathogen detection in children after two years of follow-up (Maputo Sanitation [MapSan] trial, clinicaltrials.gov: [NCT02362932][1]). We found significant reductions in Shigella and Trichuris prevalence but only among children born after the intervention was delivered. In this study, we assess the health impacts of the sanitation intervention after five years among children born into study households post-intervention. Methods and analysis We are conducting a cross-sectional household study of enteric pathogen detection in child stool and the environment at compounds (household clusters sharing sanitation and outdoor living space) that received the pour-flush toilet and septic tank intervention at least five years prior or meet the original criteria for trial control sites. We are enrolling at least 400 children (ages 29 days-60 months) in each treatment arm. Our primary outcome is the prevalence of 22 bacterial, protozoan, and soil transmitted helminth (STH) enteric pathogens in child stool using the pooled prevalence ratio across the outcome set to assess the overall intervention effect. Secondary outcomes include the individual pathogen detection prevalence and gene copy density of 27 enteric pathogens (including viruses); mean height-for-age (HAZ), weight-for-age (WAZ), and weight-for-height (WHZ) z-scores; prevalence of stunting, underweight, and wasting; and the 7- day period-prevalence of caregiver-reported diarrhea. All analyses are adjusted for pre-specified covariates and examined for effect measure modification by age. Environmental samples from study households and the public domain are assessed for pathogens and fecal indicators to explore environmental exposures and monitor disease transmission. Ethics and dissemination Study protocols have been reviewed and approved by human subjects review boards at the Ministry of Health, Republic of Mozambique and the University of North Carolina at Chapel Hill. De-identified study data will be deposited at . Trial registration number ISRCTN86084138 STRENGTHS AND LIMITATIONS OF THIS STUDY ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study is funded by the Bill & Melinda Gates Foundation (OPP1137224) with additional support from a National Institute of Environmental Health Sciences training grant (T32ES007018). The funders had no role in the study design; data collection, analysis, and interpretation; or decision to publish. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The National Health Bioethics Committee of the Ministry of Health of Mozambique gave ethical approval for this work (FWA#: 00003139, IRB00002657, 326/CNBS/21; approved: 15 June 2021) The Institutional Review Board of University of North Carolina at Chapel Hill gave ethical approval for this work (IRB#: 21-1119; approved 19 August 2021) I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes This is the protocol for an ongoing study. Upon publication of study results, the underlying individual participant data will be fully de-identified according to the Safe Harbor method and made freely available in a permanent online repository (https://osf.io/e7pvk/) in accordance with the funder's open data policies. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT02362932&atom=%2Fmedrxiv%2Fearly%2F2023%2F03%2F28%2F2022.08.19.22278991.atom