Testing wastewater for COVID-19 could give a clearer picture of spreading variants

EDMONTON -

As the Alberta government scales back PCR testing, a project testing wastewater in the province for COVID-19 could help show where the disease is spreading.

The University of Alberta and University of Calgary have been doing community wastewater testing for COVID-19 since May 2020.

Traces of COVID-19 are shed by people, whether they know they’re infected or not and end up in the wastewater. The test targets two parts of the nucleocapsid gene, a structural protein, of SARS-CoV-2 to find evidence of COVID-19.

At the beginning of 2021, they also began targeted testing, which can range from a single site, like a hospital, to a specific wing of that hospital.

“We are able to provide very accurate (information to the) community, like the town or the city,” said Dr. Xiaoli Lilly Pang, co-lead of the Pan-Alberta Network for Wastewater-based SARS-CoV-2 Monitoring.

“Long term, wastewater testing information will provide very good information to public health.”

According to Pang, they have been able to see the number of cases rising in places like Edmonton and Calgary.

As the province tries to ease pressure on lab workers by moving from PCR tests to rapid COVID-19 tests, the wastewater project could give a clearer picture of how COVID-19 is spreading in the province.

“We test everyone, so our tests have no bias, we always test everything, not like clinically with the changing policies,” said Pang. “We’re really confident in our surveillance.”

During Tuesday’s COVID-19 update, the premier said that scaling back PCR testing was necessary but that the wastewater treatment program was providing “good data on a population basis.”

“We’ve invested significantly in that program, stepped it up in the number of locations where we take samples,” added Kenney. “That’s an additional relevant data point that helps us to identify the scope of transmission.”

The other co-lead of the project, Bonita Lee, said the wastewater testing has been correlating well with the date from PCR testing since the third wave.

“It doesn’t tell you who has the disease, it doesn’t tell you whether the people have severe or mild disease… but on the other hand… when there are a lot of cases, even if the majority of them are mild, the healthcare system can still be overloaded,” said Lee.

The information could allow public health teams to identify outbreaks in communities, according to the University of Calgary.

The project is testing the wastewater of around 3.2 million people, around three-quarters of the province, added the university.

There are 17 wastewater treatment plants and 25 communities across Alberta taking part. The water is tested three times a week.

The university added that the provincial government provided $3.4-million in funding for the project.

With files from CTV News Edmonton’s Jessica Robb