Wastewater surveillance to infer COVID-19 transmission: A systematic review

Abstract

Successful detection of SARS-COV-2 in wastewater suggests the potential utility of wastewater-based epidemiology (WBE) for COVID-19 community surveillance. This systematic review aims to assess the performance of wastewater surveillance as early warning system of COVID-19 community transmission. A systematic search was conducted in PubMed, Medline, Embase and the WBE Consortium Registry according to PRISMA guidelines for relevant articles published until 31st July 2021. Relevant data were extracted and summarized. Quality of each paper was assessed using an assessment tool adapted from Bilotta et al.'s tool for environmental science. Of 763 studies identified, 92 studies distributed across 34 countries were shortlisted for qualitative synthesis. A total of 26,197 samples were collected between January 2020 and May 2021 from various locations serving population ranging from 321 to 11,400,000 inhabitants. Overall sample positivity was moderate at 29.2% in all examined settings with the spike (S) gene having maximum rate of positive detections and nucleocapsid (N) gene being the most targeted. Wastewater signals preceded confirmed cases by up to 63 days, with 13 studies reporting sample positivity before the first cases were detected in the community. At least 50 studies reported an association of viral load with community cases. While wastewater surveillance cannot replace large-scale diagnostic testing, it can complement clinical surveillance by providing early signs of potential transmission for more active public health responses. However, more studies using standardized and validated methods are required along with risk analysis and modelling to understand the dynamics of viral outbreaks.

Making waves: Wastewater surveillance of SARS-CoV-2 in an endemic future

“…The presence of SARS-CoV-2 RNA in wastewater was first demonstrated in the Netherlands, United States, Spain, and Australia in April 2020 ( Ahmed et al, 2020 ; Medema et al, 2020 ; Randazzo et al, 2020 ; Wu et al, 2020 ). Since then, the WBS field has undergone considerable growth in the optimization of experimental protocols ( Ahmed et al, 2022 ; Pérez-Cataluña et al, 2021 ), testing scales, and epidemiological modeling analyses ( McMahan et al, 2021 ) as well as numerous observational case studies on a local or national scale ( Shah et al, 2022 ). In April 2022, the World Health Organization (WHO) published interim guidelines for the environmental surveillance of SARS-CoV-2 as a complementary method to clinical diagnostics, thus further legitimizing WBS as an important public health tool ( World Health Organization, 2022 ).…”

Centralized and decentralized wastewater-based epidemiology to infer COVID-19 transmission – A brief review

“…Developing countries often have inadequate wastewater infrastructure, which, among many other problems, can hinder the application of WBE and further stunting monitoring efforts in the very countries that would benefit from this cost-effective surveillance approach. Due to the high proportion of households not connected to the sewage network, poor management of sewage and non-functioning operational facilities, analysis of untreated wastewater from centralized WTTPs in these countries is not representative of disease prevalence in the population [ 79 ]. A way to circumvent these limitations is the environmental surveillance of SARS-CoV-2 RNA in polluted waters.…”

Sampling strategies for wastewater surveillance: Evaluating the variability of SARS-COV-2 RNA concentration in composite and grab samples

“…However, as attested by Shah et al [29] , the data published so far are insufficient to consolidate SARS-CoV-2 monitoring via wastewater surveillance. There are important methodological aspects to be validated and optimized such as sampling strategies and experimental methods (concentration and quantification of SARS-CoV-2 RNA) [21] , [30] , [31] .…”