Alberta's COVID-19 levels in wastewater on the rise as BA.2 variant now dominant strain

Data from wastewater collection throughout Alberta shows a steady increase in cases of COVID-19.

Wastewater sampling in Calgary reached a low trend at the beginning of March, but in recent weeks has climbed up to levels not seen since mid-February.

"The wastewater testing has shown, especially in Calgary, that the number of cases is going up and the positivity rate in the people we are testing has gone up as well," said Dr. Dan Gregson, infectious diseases physician and medical microbiologist at University of Calgary's Cumming School of Medicine.

Gregson says this could indicate an increase in cases and severe outcomes in April.

"Hospital admissions lag behind the test positivity numbers," he said. "I would expect that we'll start seeing an increase in our hospitalizations over the next week or two. I just don't know how high they're going to go."

The information is collected through the Centre for Health Informatics, supervised by a team of scientists and medical experts from the University of Calgary, the University of Alberta, the Alberta government and other partners.

CTV News has reached out to the Calgary-based physician and scientist who interprets the wastewater data and will update the story when that analysis becomes available.

Dr. Gregson says the wastewater data analyzed prior to Wednesday suggests the amount of transmission going on currently is similar to the peak of Alberta's September/October wave driven by the Delta variant.

"The difference currently is our vaccination rates. Those people have had their third dose and those people who are younger and have two doses are fairly well protected against requiring hospital admission," said Gregson.

"So it's moving more rapidly through the population than prior variants. We're seeing a lot of transmission."

During Alberta's March 23 COVID-19 briefing, Alberta's Chief Medical Officer of Health Dr. Deena Hinshaw said the BA.2 variant is now the dominant strain in the province.

Hinshaw also said that the new strain is more transmissible but not evidently more severe.

"It is moving more rapidly through the population than prior variants. We're seeing a lot of transmission," said Gregson.

He added that Alberta's decision to remove public health measures from most indoor public settings requires individuals to take action to reduce their increasing risk of contracting the virus.

"Get your vaccines up to date. If you are at risk of severe disease, try and limit your contacts, use a mask in most settings indoor settings and limit your contacts with people who may be infectious.

"Unfortunately, the transmission rates look like if you haven't had COVID-19 yet, you're going to get it at some point in time. For most people who've been immunized and aren't immunocompromised that's going to be a mild to moderate infection similar to a bad flu."

Gregson said there will likely be a rise in hospitalizations.