Wastewater COVID-19 Surveillance

Measuring SARS-CoV-2 RNA (or Measuring COVID-19 indicators) in wastewater as an early indicator to help determine COVID-19 activity in the community.

As we continue to navigate the COVID-19 pandemic, a daily picture of COVID-19 activity in the community helps us determine our best collective response. 

Tracking the number of Ottawans testing positive for COVID-19 every day is one way of looking at the overall level of COVID activity; however, not everyone with COVID-19 is tested.  In addition, COVID-19 testing and obtaining results takes time. These limitations mean that the daily positive test numbers that are identified are like a partial rear-view look at COVID-19 activity in the community. Other means of determining the degree of COVID presence in Ottawa would be welcome.

Studies have shown that a significant proportion of people with active COVID-19 infections shed the coronavirus (called SARS-VCoV-2) in their stool, sometimes even before their symptoms start.   Every time an individual with COVID-19 goes to the bathroom, they flush the virus into the wastewater system.   We are fortunate in Ottawa to have the Robert O. Pickard Environmental Centre (ROPEC) which collects and treats wastewater from 91.6% of Ottawa’s population.  This allows for centralized measuring of the level of the coronavirus genetic material (known as RNA), which can help shed light on whether the number of infected people in Ottawa is increasing, decreasing or staying the same.  In essence, we are conducting a very broad COVID-19 survey to which we all contribute including those who are not getting tested themselves and those who may not even know they are infected. 

In simple terms, how does it work?

For the past several months researchers at the University of Ottawa and CHEO Research Institute working with the ROPEC staff have been conducting and refining their approach. Currently, five days a week, wastewater is collected and transported to a laboratory where viral RNA levels are immediately tested and results reported the next morning.

Thank to this innovative research at CHEO and the University of Ottawa, we are one of the first communities in North America to take the step of conducting such daily wastewater readings.  It is also important to note that for a number of reasons, there is some variability in the readings and researchers and engineers are working on improving the methodology. Some of the reasons for this variability include: the level of virus in stools is fairly low; the actual number of people with COVID-19 may be quite low in relation to the total population; and wastewater is a harsh environment which may break down the viral RNA resulting in lower readings.  Nonetheless, ongoing research has observed a strong correlation with other established COVID-19 measures.

There are indications we can learn about COVID-19 in our community by analyzing our wastewater possibly days before we learn it from other methods such as swabs taken from a person’s nose or throat and observable reports of illness. As this research continues to move forward, measuring COVID-19 in wastewater has the potential to help Ottawa Public Health and other health agencies gauge the level of COVID-19 presence in our community, possibly even working as an early warning system as we continue to find better leading (early) indicators to help in the fight against COVID-19.

This research is a collaboration is co-led by Robert Delatolla, Associate Professor at the uOttawa Faculty of Engineering, and Dr. Alex MacKenzie, Senior Scientist at the CHEO Research Institute.

Learn more about the Novel Coronavirus COVID-19 and the current situation in Ottawa.