Evidence of COVID-19 in wastewater continues to drop in Saskatoon, Prince Albert

Researchers at the University of Saskatchewan say levels of COVID-19 have continued to decline in wastewater in Prince Albert, Saskatoon and North Battleford.

On Monday, researchers with the university's Global Water Futures program released their weekly wastewater report. Sewage samples are taken from water treatment plants and tested for levels of COVID-19. The results can be used to determine whether case numbers are expected to rise or fall in the short term future.

The latest report shows viral load drops of 27.2 per cent in Saskatoon, 45.4 per cent in Prince Albert and 38.4 per cent in North Battleford.

Researchers say the decline could be due to a large fraction of the population already being infected in previous waves of the disease, as well as people having received immunizations.

"I think what we're seeing here is that the pool of individuals that are available for recent reinfection is declining," said Markus Brinkmann, director of the toxicology centre at the University of Saskatchewan.

"When you look at the basic infection models, that's what you would expect once you have reached a very high level of infection across the population."

Meanwhile, Regina saw a huge spike in its wastewater numbers last week. Researchers at the University of Regina said they believed two new Omicron subvariants, BQ 1.1 and BQ 1.11 could be driving high results in the city.

The BQ subvariants were spotted in Regina wastewater samples last month and are believed to be responsible for growing COVID numbers across the United States and elsewhere.

Brinkmann said the U of S has not seen the BQ subvariants in its studies and the team is currently working on implementing a test that can search for it.

He noted that Saskatoon and Regina are two different cities and that it is entirely possible that their COVID numbers would not synchronize with each other.

Brinkmann said that while the most recent test results seem to be good news for the city in the short run, the team is still monitoring results closely as winter approaches.

"For the time being, these numbers are really encouraging, especially with other respiratory viruses and potentially a flu season around the corner that might be a bit more severe than in previous years," said Brinkmann.

"We are really closely watching what's happening here in the wastewater and as soon as we see the trend reverse, obviously we get a bit more concerned."