Wastewater data shows COVID-19 viral levels dropping, but Sask. not in the clear yet: researchers

Wastewater data shows COVID-19 viral levels dropping in four of Saskatchewan’s cities.

According to the most recent weekly data, Regina’s viral levels dropped roughly 50 per cent from the week before, which puts the city at similar levels it saw when the Omicron wave began ramping up.

However, levels are still “way above what we had at the highest level in the Delta wave,” according to University of Regina molecular biologist Tzu-Chiao Chao.

He says levels are trending in the right direction, but the decline is inconsistent.

The most recent data shows a “slight slowdown” in the dropping levels. Whether that continues will depend on behaviors over the coming weeks, Chao says. Given the high level of transmission, he calls the situation volatile.

“I wouldn’t say we’re in the clear,” Chao said.

“It requires each infected individual to add a couple more contacts and then the trend could go in the other direction again.”

Saskatchewan removed the last of its COVID-19 restrictions on Monday.

According to Chao, the last time mask mandates were lifted, Regina had much lower viral levels than it does now. Even then, he says transmission rebounded.

“We are still at a very high level and if we see rebounds, the rebounds will be much higher than in the past,” he said.

Dr. Alex Wong, an infectious disease physician in Regina, hopes the drop in wastewater viral levels can be sustained. However, he expects hospitalizations and ICU admissions to lag by two or three weeks.

“COVID is still very much present,” he said.

“There is still a huge amount of Omicron being transmitted across the province, it feels like more so in rural settings now.”

Wong says transmission in rural communities tends to lag from what is happening in urban centers. Anecdotally, the doctor is hearing that many of the rural patients who test positive for COVID-19 have to come to Regina and Saskatoon for care.

Saskatoon’s wastewater data shows viral levels decreased 62 per cent compared to the previous week, which saw a major spike.

Markus Brinkmann, University of Saskatchewan associate professor and wastewater researcher, calls the decline “encouraging” and hopes the province is past the peak of the Omicron wave.

“If you see a drop of 62 per cent then that’s less than half the viral load, so that’s something significant,” Brinkmann said.

“We should wait another week or so to speak of a fairly solid trend.”

Prince Albert saw a drop of 22 per cent, while North Battleford’s decrease was 31 per cent.

Brinkmann said policy changes and behaviors can trigger new outbreaks, adding it could be two weeks before we see what impact, if any, lifting restrictions has on wastewater data.

“We’re not actually looking at a crystal ball we can just basically describe the trends that we will see over the short and medium term,” Brinkmann said.

Both Regina and Saskatoon wastewater samples indicate only low levels of the more transmissible Omicron BA.2 subvariant. BA. 1 remains the dominant strain across the province.

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