The added value of water, sanitation and hygiene interventions to mass drug administration for reducing the prevalence of trachoma: a systematic review

Methodological quality of the review: Low confidence

Author: Travers A, Strasser S, Palmer SL, Stauber C

Geographical coverage: Ethiopia, Vietnam and Australia

Sector: Trachoma

Sub-sector: WASH, mass drug administration, prevalence

Equity focus: None specified

Review type: Effectiveness review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background:

Trachoma is the leading cause of infectious blindness worldwide. The SAFE strategy, the World Health Organisation-recommended method to eliminate blinding trachoma, combines developments in water, sanitation, surgery and antibiotic treatment. Current literature does not focus on the comprehensive effect these components have on one another.

Objectives:

The present systematic review aimed to analyse the added benefits of water, sanitation and hygiene education interventions to preventive mass drug administration of azithromycin for trachoma.

Main findings:

Authors noted that in two studies, the decrease in trachoma prevalence was significant not only between the pre- and post-interventions but between the intervention and non-intervention communities. In contrast, however, the third study found a significant decline between pre- and post-intervention but not between villages. The study was unable to determine if the “E” (environmental component) added significant value to the SAFE strategy between the two villages studied.

Authors noted that one study which examined the relationship between facial cleanliness/nasal discharge showed that the non-intervention community which received only the “A” and “F” components of SAFE performed better than the intervention which had the additional “E” component. However, these were not easily correlated to the small difference in the prevalence of trachoma.

Overall, authors stated that while all studies found a significant change in the reduction of active trachoma prevalence, the research is still too limited to suggest the impact of the “F” and “E” components on trachoma prevalence and ultimately its effects on blindness.

Methodology:

The PUBMED, Lista, EBSCO and MEDLINE databases were searched using key words pairing water, sanitation and hygiene education against trachoma and either preventive chemotherapy, mass chemotherapy or antibiotic. No restrictions were put on study date, location, design or language of publication.

The primary outcome measure for this review was the prevalence of active trachoma measured as the number of participants with trachomatis inflammation follicular (TF) and/or trachomatis inflammation intense (TI) before and after intervention. Secondary outcomes included changes in knowledge, attitudes and practice specific to the risk factors associated with the prevention of trachoma through antibiotics, face washing and environmental control.

Eligible study designs included peer-reviewed studies evaluating the impact of WASH interventions on the antibiotic component of the SAFE strategy. All articles included in the review were required to report trachoma prevalence data before and after programme implementation.

Titles and abstracts found in the electronic databases were screened for relevance by one author. Authors also quality-assessed each study and assessed selection bias of included studies. A narrative approach was used to analyse the findings of studies.

Applicability/external validity:

Authors did not discuss the generalizability of findings of included studies.

Geographic focus:

Participants in included trials were residents in trachoma endemic communities from Ethiopia, Australia and Vietnam.

Summary of quality assessment:

Overall, there is low confidence in the conclusions about the effects of this study as important limitations were identified. Although authors used appropriate methods to analyse findings of included studies due to heterogeneity, methods used to screen, extract data and appraise studies were not clearly reported to understand if bias was avoided. In addition, authors did not conduct a thorough search of the literature to ensure relevant studies were not omitted.