Retrospective epidemiological analysis of SARS-CoV-2 wastewater surveillance and case notifications data - New South Wales, Australia, 2020

• Published in: Journal of water and health 2022-01, Vol.20 (1), p.103-113
• Main Authors: Camphor, H S, Nielsen, S, Bradford-Hartke, Z, Wall, K, Broome, R
• Format: Article
• Language: English
• Subjects: Australia; case notifications; Catchment area; Catchment areas; Coronaviruses; COVID-19; Detection; Disease transmission; Environmental health; Epidemiology; Health facilities; Health surveillance; Humans; New South Wales - epidemiology; Probability theory; Public health; public health response; Quarantine; Retrospective Studies; RNA, Viral; SARS-CoV-2; sars-cov-2 surveillance; Severe acute respiratory syndrome coronavirus 2; Specificity; Statistical analysis; Surveillance; viral detection; Viral diseases; Waste Water; Wastewater; wastewater epidemiology; Wastewater-Based Epidemiological Monitoring; Water sampling; Water treatment
• ISSN: 1477-8920; 1996-7829
• DOI: 10.2166/WH.2021.275

This epidemiological study analysed SARS-CoV-2 wastewater surveillance and case notifications data to inform evidence-based public health action in NSW. We investigated measures of association between SARS-CoV-2 RNA fragments detected in wastewater samples (n = 100) and case notifications (n = 1,367, as rates per 100,000 population) within wastewater catchment areas (n = 6); and evaluated the performance of wastewater testing as a population-level diagnostic tool. Furthermore, we modelled SARS-CoV-2 RNA fragment detection in wastewater given the case notification rate using logistic regression. The odds of a viral detection in wastewater samples increased by a factor of 5.68 (95% CI: 1.51-32.1, P = 0.004) with rates of one or more notified cases within a catchment. The diagnostic specificity of wastewater viral detection results was 0.88 (95% CI: 0.69-0.97); the overall diagnostic sensitivity was 0.44 (95% CI: 0.33-0.56). The probability of a viral detection result in wastewater exceeded 50% (95% CI: 36-64%) once the case rate within a catchment exceeded 10.5. Observed results suggest that in a low prevalence setting, wastewater viral detections are a more reliable indicator of the presence of recent virus shedding cases in a catchment, than non-detect results are of the absence of cases in a catchment.