Studies evaluating trachoma pre-validation surveillance in Ghana
Summary
In order to achieve the elimination of trachoma, a country needs to demonstrate that the elimination prevalence thresholds have been achieved and then sustained for at least a two-year period. Ghana achieved the thresholds in 2008, and since 2011 has been implementing its trachoma surveillance strategy. In 2015–2016, the country conducted a district-level population-based survey (two-stage cluster random sampling methodology) to provide evidence for the validation of elimination of trachoma as a public health problem.
The surveys were conducted across 18 previously trachoma-endemic districts (evaluation units (EUs)) in the Upper West and Northern Regions of Ghana. All EUs had shown to have maintained the WHO elimination threshold for trachomatous inflammation-follicular (TF) (<5.0% prevalence) in children aged 1–9 years old. The EU TF prevalence in children aged 1–9 years old ranged from between 0.09% to 1.20%. Only one EU (Yendi 0.36%; 95% CI: 0.0–1.01) failed to meet the WHO TT elimination threshold (< 0.2% prevalence in adults aged 15 and above). The EU prevalence of trichiasis (TT) unknown to the health system in adults aged ≥15 years, ranged from 0.00% to 0.36%. The findings from this survey indicate elimination thresholds have been maintained in Ghana in 17 of the 18 surveyed EUs. Only one EU, Yendi, did not achieve the TT elimination threshold. A scheduled house-by-house TT case search in this EU coupled with surgery to clear the backlog of cases is necessary in order for Ghana to request validation of elimination of trachoma as a public health problem.
Between January and April 2016, qualitative research was conducted with those people involved in the operationalisation of the trachoma surveillance system from across all levels of the health system. This assessed both successes and challenges and highlighted that further consideration needs to be given during transition planning (from intervention to elimination) as to the adaptations to the surveillance strategy required to address contextual changes that arise as a result of transmission decline.