Evaluation of a face-washing behaviour change intervention for trachoma prevention in Oromia, Ethiopia (Stronger SAFE): secondary outcomes of a cluster-randomised controlled trial.

Abstract

Facial cleanliness is a key component of the current strategy to interrupt transmission of Chlamydia trachomatis and achieve trachoma elimination but robust evidence to support its use is scarce. We aimed to evaluate the effect of a community-based, enhanced face-washing intervention for trachoma prevention. Stronger SAFE was a cluster-randomised controlled trial conducted in the Oromia region of Ethiopia. Eligible clusters (each comprising about 90 households) from zones with high prevalence of trachoma were randomly assigned (1:1:1:1) to one of four groups. Groups 1 and 3 received standard trachoma control, including routine facial hygiene messaging (control group), and groups 2 and 4 received enhanced interventions, including free-standing wash stations and multimodal, theory-based activities promoting face washing with soap (intervention group) to be implemented for 24 months. Participants and outcome assessors were not masked, but assessors were unconnected to intervention status. The primary outcome and adverse events are reported elsewhere. This analysis focused on key prespecified, secondary behavioural outcomes of observed face-washing prevalence and soap use in the intention-to-treat population of 204 households with one or more child aged 1-6 years. Outcomes were assessed via structured observation and surveys at baseline, and 3 months and 24 months after the initial intervention was first delivered (corresponding to the trial's 15-month and 36-month follow-ups after commencement of other enhanced interventions). The trial is registered with ISRCTN (ISRCTN40760473) and is complete. 68 clusters were enrolled and 34 were randomly assigned to receive the intervention between March 6, 2021, and Aug 31, 2024. At each timepoint, three households per cluster were randomly selected to be analysed for face-washing outcomes (102 households each from the control group and intervention group). At 24 months, the analysis population comprised 639 individuals in the intervention households and 652 in the control households. The enhanced intervention was associated with an increase across all key behavioural outcomes compared with the control group. At 24 months, face washing was observed in 321 of 639 individuals in the intervention group and 278 of 652 in the control group (cluster-level mean prevalence 51% [SD 15·3] vs 43% [13·3]; baseline-adjusted difference 7·3 percentage points [95% CI 0·5-14·2]). The proportion of individuals who washed their face with soap was higher in the intervention group than the control group (cluster-level mean prevalence 12% [15·3] vs 1% [3·7]; baseline-adjusted difference 11·6 percentage points [6·2-17·0]). The proportion of face washes that included soap was higher in the intervention group versus the control group (cluster-level mean prevalence 23% [25·9] vs 2% [7·3]; baseline-adjusted difference 21·0 percentage points [11·9-30·2]). Effects were more pronounced among children aged 1-6 years. 87 (85%) of 102 control households were water insecure 24 months after the intensive intervention was delivered compared with 85 (83%) of 102 intervention households (cluster-level means 9·5 L [10·8] per person vs 8·7 L [8·6]). The enhanced intervention increased soap use during face washing, but had a smaller effect on the overall prevalence of face washing. Our findings highlight the challenge of achieving hygiene behaviour change in water-scarce settings. Wellcome Trust and the Children's Investment Fund Foundation. For the Amharic and Afan Oromo translations of the abstract see Supplementary Materials section.