Wastewater Surveillance Research Group Leaves Lasting Public Health Legacy

The CoVaRR-Net Wastewater Surveillance Research Group (WWSRG) has transformed public health surveillance in Canada, pioneering wastewater and environmental monitoring to track infectious diseases.

Over the course of its existence, the WWSRG has positioned Canada as a global leader in wastewater monitoring, producing groundbreaking research and building interdisciplinary collaborations that will have lasting impacts beyond the COVID-19 pandemic.

Before the pandemic, wastewater monitoring in Canada was primarily used for public health insight, including observing illicit drug use and detecting poliovirus. However, as the pandemic rapidly evolved into a public health emergency, wastewater became an essential public health tool. “Wastewater monitoring across Canada went from a handful of sites to over 260 locations at some point monitoring COVID-19,” explains Dr. Rob Delatolla, Director of CoVaRR-Net’s Wastewater Surveillance Research Group and Professor in the Department of Civil Engineering at the University of Ottawa.

At multiple points throughout the pandemic, when routine laboratory testing was no longer possible because COVID-19 case numbers became too high and testing centres could no longer keep up, wastewater monitoring provided a cost-effective, real-time indicator of infectious disease trends.

“Right at the beginning of the Omicron wave, blood testing numbers dropped sharply,” says Dr. Delatolla. “When that happened, the metric completely changed as testing blood samples became limited. However, wastewater monitoring was still ongoing. That’s when we started to understand its value. It’s economical, technically straightforward to do, and it can provide us the data that can help us understand when the next pandemic or health threat is coming.”

The WWSRG made significant contributions to wastewater monitoring and optimized methods. This made the wastewater data more reliable and readily available to integrate with public health to predict hospitalizations and track disease trends.

Additionally, the team’s research extended beyond COVID-19, applying wastewater monitoring techniques to track respiratory syncytial virus (RSV), tuberculosis, and influenza. Their hard work, dedication, and expertise proved that wastewater is a reliable early-warning system for multiple pathogens, creating enormous value for public health strategies worldwide.

“Using wastewater, we could predict the start of the RSV season  and this, for instance, could help hospitals prepare for an influx of patients,” Dr. Delatolla notes. “If Ontario used wastewater monitoring for RSV, we could prevent 250 hospitalizations, save 950 doctor visits, and save the province about $3.5 million annually.”

One of the WWSRG’s defining achievements was its commitment to interdisciplinary collaboration. The group brought together engineers, microbiologists, epidemiologists, statisticians, and public health officials to refine wastewater monitoring methodologies and integrate the findings into public health decision-making. This collaborative framework was key to establishing wastewater monitoring as a core component of pandemic preparedness. The WWSRG prioritized equitable access to the data, expanding surveillance infrastructure and capacity in underserved and remote Indigenous communities.

Despite its groundbreaking work, the WWSRG faces an uncertain future. As CoVaRR-Net operations end on March 31, 2025, Dr. Delatolla points out that the once-cohesive research network is fragmenting. “We’ve met and were linked with amazing friends and colleagues through this process,” he says. “But you know how it is: without an official network, people go back and do their thing and then, over time, it’s not the same… as opposed to having a strong network where you have this overarching structure that’s keeping us all together.”

Nonetheless, Dr. Delatolla believes the group’s legacy is firmly established. Its methodologies and protocols continue to inform public health strategies, ensuring wastewater monitoring remains an integral part of infectious disease oversight. “We’ve advanced the knowledge so far that I think – and hope – it’s going to be a valuable tool for the next pandemic. That’s the legacy.”

As Canada and the global scientific community build on the WWSRG’s efforts, the goal remains that wastewater monitoring will continue to evolve, aid routine public health monitoring, and shape the future of pandemic preparedness for years to come — at least in Canada, if not in countries around the world.

Wastewater Proved to Be an Accurate Early Warning System

This figure illustrates the association between wastewater viral signals and hospitalizations in Ottawa from June 16, 2020 to November 13, 2022. The blue area shows the number of patients in hospitals caused by COVID-19 at that specific time point. The orange curve shows the 7-day moving average of wastewater viral signal. The huge increase in wastewater viral signal in the BA.2 wave was due to health protections being lifted in March 2022.