Sewage is the new gold for the public health scientists who track viruses

A provincial program that tracks the rise and fall of COVID-19 infections in Ontario communities through the monitoring of wastewater is expanding to include influenza, according to a lead investigator with the program at Western University. 

Ontario's COVID-19 wastewater surveillance program, run by a consortium of universities across the province, monitors sewage at 59 wastewater treatment plants in 34 different health units throughout the province in order to pinpoint where and when new waves of COVID-19 infections may emerge. 

Now the province is expanding the program to include influenza to get ahead of future outbreaks, especially as the fall chill returns, sending more people indoors and in turn, creating ideal conditions for viruses to circulate. 

"It's really useful for any respiratory virus, really, because we don't have good numbers on the number of people that are infected," said Chris DeGroot, the lead investigator for the project launched in response to the pandemic in 2021. "By looking to the wastewater, we kind of get a composite of everything that's going on among all the individuals in our community."

The project sees samples taken from wastewater treatment plants tested in labs, using a method many might be familiar with in a post-pandemic world — a PCR test.

The data collected from these tests has varied in its uses, from individuals using publicly available numbers to assess their risk levels, to informing choices surrounding vaccination.

"Public health is really using it just to be more informed. To get a better idea of when the respiratory virus season is starting, when they should really start to push their messaging to get vaccinated," said DeGroot.

DeGroot says monitoring wastewater can even be useful in times like now, where there's less viral spread. This summer has been a rare occasion of generally low COVID-19 levels, but according to DeGroot, surges can happen any time, especially when seasons change and weather becomes cooler.

Monitoring wastewater can also tell researchers more about our collective health.

"Any virus you can imagine. People have tested for polio, various STI's using different laboratory techniques," said DeGroot, adding he believes the possibilities are endless in terms of what can be measured in wastewater.

"You can look at consumption of drugs, either pharmaceutical or or illegal drugs. You can see what people are consuming."

Funding for the project won't last forever though, with a deadline of March 2024.

DeGroot and his colleagues hope for an extension, but he says he doesn't believe it'll be necessary to ensure the project continues.

"We'll keep going for sure. You know we have other research grants and we're all very interested and committed to this work," he said.

"We just don't know if we can maintain the same scale that's possible with the with the government funding we received, but we'll definitely be continuing with wastewater surveillance for the foreseeable future."