‘The lockdown is working’: COVID-19 viral loads in Ottawa wastewater plateauing

Wastewater data in Ottawa is indicating a step in the right direction in the city's fight against COVID-19.

According to Dr. Tyson Graber, a research associate with CHEO, the COVID-19 viral loads in Ottawa's wastewater are showing markers that indicate levels started to plateau at the start of the new year.

“Cases were quite high throughout most of the month of January and the wastewater indicated that we weren't really going up like a rocket,” Dr. Graber explains. “It was a steady burn, steady increase and then it kind of plateaued over the last of couple weeks.”

He adds the data from the past three or four days is demonstrating a slow but steady decrease. The wastewater levels have been monitored since April and have been fluctuating for months.

Graber explains that the city was starting to see an increase around Christmas.

Cases, he adds, were high during January and waste water showed that Ottawa was on a “steady burn” upwards.

But in the past few weeks, the dip started to happen.

“The lockdown is working, for sure,” Graber said. “That is consistent with waste water data from other parts of the world where there’s been lockdowns. The thing with waste water is that you can certainly detect increases in disease really quickly, but on the other side as we come down from that peak during the lockdown, the waste water is quite slow. That’s because people fecally shed fragments of this virus for long periods of time, even after they haven’t been symptomatic anymore. So it is a slow and steady decrease.”

“I think we’re in a good place right now,” Graber said. “Hopefully that trend continues but we’re still at a heightened level in the city.”

When researchers compare where Ottawa is today to what they’ve collected over that time period, Graber says the city is about in the mid-range right now.

To be more specific, Graber says the city is back to when it was in October, when there was heightened transition — so not quite where we were in July, when cases were low.

In the meantime, the doctor says the wastewater levels are currently unable to detect variants of the novel coronavirus.

“If this trend continues,” he says, “we’re looking good going into next week.”

– With files from Dani-Elle Dubé