Effectiveness of poliovirus environmental surveillance in Ghana: an indicator-based performance evaluation across seven regions, 2018–2022

OBJECTIVE: To evaluate the performance of Ghana's environmental surveillance (ES) system for poliovirus (PV) detection from 2018 to 2022 using standardised indicators developed by the WHO and the US Centers for Disease Control and Prevention. DESIGN: A retrospective performance evaluation using 10 key indicators benchmarked against global targets for PV surveillance. SETTING: Seven regions across Ghana, participating in the national ES programme implemented under the Global Polio Eradication Initiative. SURVEILLANCE COVERAGE: Wastewater sampling was conducted at designated ES sites, supported by field collection teams and laboratory personnel responsible for sample acquisition, processing and reporting of PV detection results. OUTCOME MEASURES: Detection rates of PV and non-polio enteroviruses (NPEVs), timeliness of sample collection and reporting, data quality and system stability. RESULTS: A total of 738 wastewater samples were collected. The system demonstrated high sensitivity, detecting circulating vaccine-derived PV type 2 in 51 (6.9%) of samples, Sabin PV types 1 and 3 in 61 (9.5%) and 114 (17.8%), respectively, and NPEVs in 491 (66.5%) of samples. Over 80% of samples met the recommended 21-day collection-to-reporting time frame. Data quality exceeded the ≥80% threshold, and workflows remained stable throughout the evaluation period. CONCLUSIONS: Ghana's ES system for PV was found to be flexible, stable and effective in generating high-quality data for early detection and public health response. These findings underscore the system's critical role in supporting polio eradication efforts and highlight its potential as a model for surveillance in similar settings.