The virus that causes COVID-19 infection (SARS-CoV-2) can be detected in the stool of infected people over a significant portion of their illness. This provides an opportunity to test and monitor wastewater (sewage) for the presence of COVID-19 in communities and institutional settings (e.g. long-term care facilities) without the need for individual testing. Wastewater surveillance can also be used to monitor the circulation of variants of concern (VOC) and, in some circumstances, can be used as an early indicator for the presence of COVID-19 infections not yet detected by traditional clinical surveillance.
The Public Health Agency of Canada (PHAC) is working in collaboration with other federal departments, provincial, territorial and municipal governments and academia across Canada to establish a pan-Canadian wastewater surveillance network capable of monitoring the spread of COVID-19 in Canada (see Map and Critical Path documents). Wastewater has already been used to show early detection of COVID-19 in some Canadian jurisdictions prior to an increase of clinically diagnosed cases. As COVID-19 can be characterized by symptomatic and asymptomatic infection, it is important to identify the presence of undiagnosed cases to minimize the likelihood of outbreaks. Even a few days of early warning can be critical to the success of public health interventions and can be an important source of information for public health action.
In addition to COVID-19, wastewater surveillance can be used to monitor other public health threats, including the presence of antimicrobial resistance, additional communicable diseases (e.g. Tuberculosis) and chemical markers indicating the health of a community (e.g. the use of opioids).
Links to documents
Map of Pan-Canadian Wastewater Network
Current and Past Webinars
- PHAC hosted a Webinar entitled “Moving SARS-CoV-2 signals in Wastewater to Public Health Action” on April 1, 2021. Presentations covered laboratory methods, public health interpretation survey results, and two case studies (Ottawa and Northwest Territories).
Publications and Reports
- Barker at al. (2021) – MMMVI: Detecting SARS-CoV-2 Variants of Concern in Metagenomic Samples
- Chik et al. (2021) – Comparison of approaches to quantify SARS-CoV-2 in wastewater using RT-qPCR: Results and implications from a collaborative inter-laboratory study in Canada
- Daigle et al. (2021) – A sensitive and rapid wastewater test for SARS-COV-2 and its use for the early detection of a cluster of cases in a remote community
- Landgraff et al. (2021) – Metagenomic sequencing of municipal wastewater provides a near-complete SARS-CoV-2 genome sequence identified as the B.1.1.7 variant of concern from a Canadian municipality concurrent with an outbreak.
- Nourbakhsh et al. (2021) – A Wastewater-Based Epidemic Model for SARS-CoV-2 with Application to Three Canadian Cities
- Peterson et al. (2021) – RT-qPCR detection of SARS-CoV-2 mutations S 69-70 del, S N501Y and N D3L associated with variants of concern in Canadian wastewater samples
Guidance Document for Wastewater Surveillance
Public Health Agency of Canada Wastewater Working Groups and Meetings
The Public Health Agency of Canada is leading working groups and meetings related to wastewater surveillance for COVID-19 to discuss sampling and laboratory methods, data models and modelling and public health action and response. There are currently four working groups and meetings are held weekly or bi-weekly.
SARS-CoV-2 Variants of Concern in Wastewater
This working group brings together researchers, academic and government partners across Canada working on wastewater surveillance to discuss detection of variants of concern/interest in wastewater and interpretation of results. The meeting highlights key issues related to variants of concern/interest detection and sequencing and all laboratories or surveillance programs across the country to provide an update and share their experiences.
Wastewater Laboratory Detection of SARS-CoV-2 Working Group
This working group brings together laboratories across Canada conducting wastewater testing and surveillance for SARS-CoV-2 to discuss methods (e.g. PCR, QA/QC), sampling issues, data interpretation, reporting of results, and any other topics related to laboratory methods for detection.
Wastewater SARS-CoV-2 Surveillance Updates
This working group brings together wastewater surveillance partners across the country to create a forum for moving wastewater surveillance to public health action. This working group builds the connections between environmental sampling groups, laboratories, academia and public health to discuss sampling strategies, data interpretation and public health reporting and action.
Data Modelling and Epidemiological Interpretation Working Group
This working group brings together modellers and epidemiologists from all levels of government and academia to discuss modelling, modelling methods and interpretation of wastewater surveillance results and as they relate to clinical surveillance.
To attend any of these meetings please contact: firstname.lastname@example.org