© Provided by Edmonton Journal Gold Bar Wastewater Treatment Plant at 10977 50 St. in Edmonton on Sunday, Jan. 9, 2022. Alberta is currently using wastewater testing to monitor the spread of the COVID-19 Omicron variant.The level of COVID-19 indicators in Edmonton wastewater has soared well above where it was in any other wave of the pandemic but experts say it’s too soon to predict whether this wave has peaked and how bad the increased pressure from the Omicron variant could get on the province’s health-care system.
According to data collected by researchers from the University of Alberta and University of Calgary, the level of COVID-19 viral RNA in wastewater at the Edmonton testing site jumped to 595.7 copies per 100 ml by Jan. 3 from 153.9 copies per 100 ml on Dec. 28. The most recent number from Jan. 12 sits at 525.7.
A similarly shaped trajectory can be seen in water from the Fort Saskatchewan test site which covers portions of the greater Edmonton area.
Edmonton’s highest peak during previous waves of the pandemic was in December 2020 when it hit 168.5 per 100 ml.
Bonita Lee, an associate professor in pediatrics at the University of Alberta and co-lead of the study into Alberta’s wastewater, said this type of testing, which has been happening for the last 18 months and measures the amount of viral RNA shed and flushed down the toilet, shows the overall disease burden in a community but doesn’t provide details such as how old someone is or how severe their case is.
“One thing we can all imagine is if there is a lot of people with Omicron, then proportionately people who are admitted to hospital, whether it is because of COVID or they were admitted for different reason but they happen to have COVID, will increase the burden of COVID cases in the hospital,” she said.
“Because COVID patients require isolation, it does have resource implications for the hospital, whether it is the general unit or the ICU. It also affects our health-care workforce.”
The number of COVID-19 cases in Alberta has soared due to the Omicron variant and hospitalization numbers are climbing. Doctors have raised concerns about the pressure the surge in infections is putting on the system both due to the increase in patients requiring care and a growing number of health-care workers being unable to work due to illness or exposure to the virus.
With previous variants, a spike in COVID-19 in the wastewater corresponded to an increase in clinical cases in hospital or the ICU about a week later. But there are still too many unknowns to say for sure whether Omicron will behave the same way, said U of A’s second co-lead of the study Dr. Xiaoli Lilly Pang, a professor of laboratory medicine and pathology.
There are still unanswered questions about why the latest variant is so transmissible and how it sheds into the water compared to earlier variants, she said.
“Even though the wastewater seems to have stabilized in that higher level, we are still not 100 per cent sure,” she said.
Lee said the prevalence of the viral RNA in the wastewater means that anyone with symptoms should take the necessary precautions, including isolating, to help slow the spread.
“Not everyone needs to be tested. Hand washing is still important … keep the social groups small and physical distancing is so important,” she said.
At a news conference Thursday, Alberta’s chief medical officer of health Dr. Deena Hinshaw said it’s too early to know whether the levels of COVID indicators in wastewater have peaked.
“Independent of that timing of the peak, I think it’s really critical to remember that in any wave, we see half of our cases in the second half of the wave and therefore we need to remain cautious,” she said.
“Transmission is still very high and so while we watch those wastewater indicators very closely, our positivity rates are still extremely high, and transmission has never been higher. So caution is appropriate.”
— With files from Jason Herring
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