Civil and Environmental Engineering, Tufts University, Medford, MA, USA; Civil and Environmental Engineering, Stanford University, Stanford, CA, USA.
Civil and Environmental Engineering, Stanford University, Stanford, CA, USA; Energy and Resources Group, University of California Berkeley, Berkeley, CA, USA.
Lancet Glob Health. 2019 Sep;7(9):e1247-e1256. doi: 10.1016/S2214-109X(19)30315-8.
Previous blinded trials of household water treatment interventions in low-income settings have failed to detect a reduction in child diarrhoea. Technological advances have enabled the development of automated in-line chlorine dosers that can disinfect drinking water without electricity, while also allowing users to continue their typical water collection practices. We aimed to evaluate the effect of installing novel passive chlorination devices at shared water points on child diarrhoea prevalence in low-income, densely populated communities in urban Bangladesh.
In this double-blind cluster-randomised controlled trial, 100 shared water points (clusters) in two low-income urban communities in Bangladesh were randomly assigned (1:1) to have their drinking water automatically chlorinated at the point of collection by a solid tablet chlorine doser (intervention group) or to be treated by a visually identical doser that supplied vitamin C (active control group). The trial followed an open cohort design; all children younger than 5 years residing in households accessing enrolled water points were measured every 2-3 months during a 14-month follow-up period (children could migrate into or out of the cluster). The primary outcome was caregiver-reported child diarrhoea (≥3 loose or watery stools in a 24-h period [WHO criteria]) with a 1-week recall, including all available childhood observations in the analyses. This trial is registered with ClinicalTrials.gov, number NCT02606981, and is completed.
Between July 5, 2015, and Nov 11, 2015, 100 water points with 920 eligible households were enrolled into the study and randomly assigned to the treatment (50 water points; 517 children at baseline; 2073 child observations included in the primary analysis) or control groups (50; 519; 2154). Children in the treatment group had less WHO-defined diarrhoea than did children in the control group (control 216 [10·0%] of 2154; treatment 156 [7·5%] of 2073; prevalence ratio 0·77, 95% CI 0·65-0·91). Drinking water at the point of collection at treatment taps had detectable free chlorine residual 83% (mean 0·37 ppm) of the time compared with 0% at control taps (0·00 ppm).
Passive chlorination at the point of collection could be an effective and scalable strategy in low-income urban settings for reducing child diarrhoea and for achieving global progress towards Sustainable Development Goal 6.1 to attain universal access to safe and affordable drinking water. Targeting a low chlorine residual (<0·5 ppm) in treated water can increase taste acceptability of chlorinated drinking water while still reducing the risk of diarrhoea.
The World Bank.
先前在低收入环境中进行的家庭水处理干预措施的盲法试验未能检测到儿童腹泻的减少。技术进步使能够开发出自动化的在线氯剂量器，无需电力即可对饮用水进行消毒，同时也允许用户继续进行其典型的集水实践。我们旨在评估在孟加拉国两个低收入、人口密集的城市社区的共享供水点安装新型被动氯化设备对儿童腹泻流行率的影响。
在这项双盲、整群随机对照试验中，孟加拉国两个低收入城市社区的 100 个共享供水点（群）被随机（1:1）分配到在收集点自动氯化饮用水，由固体片剂氯剂量器（干预组）或由视觉上相同的剂量器提供维生素 C（活性对照组）进行处理。该试验采用开放队列设计；在 14 个月的随访期间（儿童可以在群内或群外迁移），每 2-3 个月对居住在使用登记供水点的所有 5 岁以下儿童进行测量。主要结局是看护人报告的儿童腹泻（24 小时内≥3 次稀便或水样便[世界卫生组织标准]），并在 1 周内进行了回顾，包括分析中所有可用的儿童观察结果。这项试验在 ClinicalTrials.gov 注册，编号为 NCT02606981，现已完成。
2015 年 7 月 5 日至 2015 年 11 月 11 日，有 100 个供水点和 920 个合格家庭参加了该研究，并被随机分配到治疗组（50 个供水点；基线时 517 名儿童；纳入主要分析的 2073 名儿童观察结果）或对照组（50 个；519 个；2154 个）。治疗组儿童的世界卫生组织定义腹泻少于对照组儿童（对照组 2154 名儿童中有 216 名[10.0%]；治疗组 2073 名儿童中有 156 名[7.5%]；患病率比 0.77，95%CI 0.65-0.91）。与对照组的 0%（0.00 ppm）相比，治疗水龙头的收集点处饮用水中的游离氯残留有 83%（平均 0.37 ppm）的时间可被检测到。
在低收入城市环境中，在收集点进行被动氯化可能是一种有效且可扩展的策略，可用于减少儿童腹泻，并为实现可持续发展目标 6.1 中的全球进展做出贡献，即实现普遍获得安全和负担得起的饮用水。将处理水中的低氯残留量（<0.5 ppm）作为目标，可以提高氯化饮用水的口感接受度，同时仍降低腹泻风险。
世界银行。
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