Trachoma control using water, sanitation, and hygiene – Authors' reply
Authors: Solomon Aragie, Thomas M Lietman, Jeremy D Keenan
Journal: The Lancet Global Health (2022)

Observational studies have found an association between trachoma and indicators of water, sanitation, and hygiene (WASH). Clean faces, use of soap, reduced distance to water, and access to a latrine have all been found to be associated with reduced prevalence of trachoma and ocular Chlamydia trachomatis infection.1Stocks ME Ogden S Haddad D Addiss DG McGuire C Freeman MC Effect of water, sanitation, and hygiene on the prevention of trachoma: a systematic review and meta-analysis.PLoS Med. 2014; 11e1001605Crossref Scopus (138) Google Scholar These observational studies served as the motivation for the WASH Upgrades for Health in Amhara (WUHA) trial,2Aragie S Wittberg DM Tadesse W et al.Water, sanitation, and hygiene for control of trachoma in Ethiopia (WUHA): a two-arm, parallel-group, cluster-randomised trial.Lancet Glob Health. 2022; 10: e87-e95Summary Full Text Full Text PDF PubMed Scopus (6) Google Scholar a cluster-randomised trial designed to assess the effect of a comprehensive community-based WASH intervention on ocular chlamydia. Changing hygiene behaviours is a challenging endeavour, and we agree with Hugh Taylor that assessment of intermediate outcomes is important for identifying whether the WASH intervention resulted in the intended changes in hygiene. The WUHA trial found statistically significant improvements in various observed and self-reported hygiene indicators among intervention communities—including face-washing with soap—suggesting that the intervention did indeed have a positive effect on the hygiene status of community members in the intervention clusters.3Aragie S Tadesse W Dagnew A et al.Changing hygiene behaviours: a cluster-randomized trial, Ethiopia.Bull World Health Organ. 2021; 99 (72A): 762Crossref PubMed Scopus (4) Google Scholar Despite the observed improvements in hygiene we were unable to detect a difference in ocular chlamydia between the intervention and control groups after 3 years.2Aragie S Wittberg DM Tadesse W et al.Water, sanitation, and hygiene for control of trachoma in Ethiopia (WUHA): a two-arm, parallel-group, cluster-randomised trial.Lancet Glob Health. 2022; 10: e87-e95Summary Full Text Full Text PDF PubMed Scopus (6) Google Scholar Facial cleanliness, typically defined as ocular discharge, nasal discharge, or face flies, is a plausible mediator of a potential association between WASH and trachoma because ocular and nasal secretions harbour chlamydia organisms. Thus, cleaner faces might be less likely to transmit ocular strains of chlamydia. We prespecified facial cleanliness as an intermediate outcome, to be assessed by masked grading of face photographs.4Wittberg DM Aragie S Tadesse W et al.WASH Upgrades for Health in Amhara (WUHA): study protocol for a cluster-randomised trial in Ethiopia.BMJ Open. 2021; 11e039529Crossref PubMed Scopus (8) Google Scholar Photograph grading is being completed at Gondar University, Ethiopia, and this outcome will be reported separately once analysed. However, it is worth noting that the facial cleanliness indicator does not necessarily precede ocular chlamydia infection on the causal pathway, since ocular infections can cause ocular secretions and, hence, an unclean face. And it is also possible that a WASH intervention could have an effect on trachoma through mechanisms other than facial cleanliness (eg, reduction of C trachomatis on fingers and fomites, or reduction of flies by reducing human faeces). The WUHA study area had been treated with 7 years of annual mass azithromycin distributions. Mass azithromycin administration has been shown to be extremely effective for reducing ocular chlamydia infection and thus, the prevalence of ocular chlamydia was expected to be low at the beginning of the study.5Lietman TM Ayele B Gebre T et al.Frequency of mass azithromycin distribution for ocular chlamydia in a trachoma endemic region of Ethiopia: a cluster randomized trial.Am J Ophthalmol. 2020; 214: 143-150Summary Full Text Full Text PDF PubMed Scopus (6) Google Scholar Concurrent mass drug administrations could have overwhelmed the effect of the WASH intervention, thus masking any true effect of WASH on trachoma. In hindsight, the high transmission of trachoma in the study area might have been too strong for a WASH intervention alone. Therefore, we are performing WUHA II—a continuation trial that maintains the original WASH intervention randomisation allocation, but adds mass azithromycin distributions to all study communities.4Wittberg DM Aragie S Tadesse W et al.WASH Upgrades for Health in Amhara (WUHA): study protocol for a cluster-randomised trial in Ethiopia.BMJ Open. 2021; 11e039529Crossref PubMed Scopus (8) Google Scholar WUHA II will investigate whether a trachoma intervention addressing the antibiotic (A), facial cleanliness (F), and environmental improvements (E) components of the SAFE strategy will result in reduced ocular chlamydia compared with antibiotics alone. We declare no competing interests. Water, sanitation, and hygiene for control of trachoma in Ethiopia (WUHA): a two-arm, parallel-group, cluster-randomised trialAn integrated WASH intervention addressing the F and E components of the SAFE strategy did not prevent an increase in prevalence of ocular chlamydia following cessation of antibiotics in an area with hyperendemic trachoma. The impact of WASH in the presence of annual mass azithromycin distributions is currently being studied in a follow-up trial of the 40 study clusters. Continued antibiotic distributions will probably be important in areas with persistent trachoma. Full-Text PDF Open AccessTrachoma control using water, sanitation, and hygieneTrachoma remains a neglected tropical disease, causing blindness or visual impairment in 1·9 million people and it is responsible for 1·4% of all blindness, worldwide.1 It affects communities living in poor, rural areas in low-income countries where access to water, sanitation, and hygiene (WASH) is scarce.1–3 Sub-Saharan Africa is the most affected region, where trachoma is hyperendemic in some regions.2,4 The SAFE strategy —which has been mandated by WHO for the elimination of trachoma—outlines measures to manage the disease and has been implemented in trachoma endemic countries since 1998. Full-Text PDF Open AccessTrachoma control using water, sanitation, and hygieneIt was most interesting to read the Article by Solomon Aragie and colleagues1 and the accompanying Comment by Robert Ntozini2 (January, 2022) on the role of a water, sanitation, and hygiene (WASH) intervention on the possible recrudescence of trachoma after the cessation of mass antibiotic distribution with azithromycin. Of course, a WASH approach should cover the F, facial cleanliness, and the E, environmental improvement, components of the SAFE strategy to eliminate blinding trachoma. The mass antibiotic distribution provides the A component, and trichiasis surgery the S. Full-Text PDF Open Access