Decline in Toronto's COVID-19 infections could be slowing or plateauing: wastewater data

Newly released wastewater data suggests that the recent decline in COVID-19 transmission in Toronto could be slowing or even plateauing but the city’s top health official says that she still remains cautiously optimistic about the weeks ahead.

The data, which was posted to the city’s website on Friday morning, provides the most detailed look yet at the results of a wastewater surveillance project being conducted in collaboration with researchers from Ryerson University and the University of Toronto.

It shows that at three of the city’s four water treatment plants the so-called “wastewater signal” meant to reflect the levels of COVID-19 detected in sewage samples saw “little to no change” over the last 30 days, after previously being on the decline.

Meanwhile, the wastewater signal at Toronto’s other water treatment plant, located in North York, saw a “statistically significant” increase over the same time period.

Discussing the data with reporters at a briefing on Friday, Toronto’s Medical Officer of Health Dr. Eileen de Villa conceded that it points to a decline in transmission that could now be “showing some signs of slowing or plateauing.”