A downward trend in Ontario's COVID-19 wastewater signal

A snapshot of Ontario's COVID-19 outbreak data shows the province's infection rate is falling after a holiday spike.

According to Public Health Ontario's latest update on Feb. 8, the province's wastewater alert stood at about 0.7 at the end of January. At the end of December, the marker reached 2.3 in what some health experts described as a wave of infections.

“We had a spike in sewage detections in December and January, and then it started going down after the holiday season and certainly continues to trend in the right direction,” said Unity Health Network infectious disease specialist Dr. Isaac Bogoch. CTV News Toronto on Monday.

The presence of COVID-19 in wastewater appears to be decreasing in all regions surveyed by Ontario Public Health, with the exception of northwestern Ontario, where the signal actually increases to 1.2.

While promising, wastewater data only shows part of the province's COVID-19 picture, Bogoc cautions.

“If the question is: How are we doing with COVID? Answer: You have to look at multiple metrics, right? Because no metric is perfect, including wastewater,” he explained, adding that factors such as hospitalizations, test positives and number of tests completed help add context.

Although Ontario is no longer testing or reporting COVID-19 infections as it did in 2020 and 2021, publicly available data also show a downward trend in other key indicators.

Ontario's wastewater COVID-19 data is shown in this image. (Ontario Public Health)

As of February 3, 81 people were hospitalized with the virus, compared with 396 hospitalizations in early December. Meanwhile, the test positivity rate drops from 43.1 percent at the end of November to 21.5 percent in the last week of January.

While the data is “not perfect,” Bogoch says putting it all together helps show how widespread COVID-19 is in the province, especially when testing and reporting aren't as widespread as they used to be.

“But when you put all the pieces together, even if they're imperfect bits of data, it paints a picture, and that picture is still here. COVID is still a problem. But we're seeing less spread of COVID now than we did during the holiday season,” he said.