Alberta scales back COVID variant surveillance nearly 3 years into the pandemic

A specialized diagnostics team at Alberta Precision Laboratories has developed screening tests for variants as SARS-CoV-2 evolves. Starting Thursday, the province will focus surveillance on genome sequencing to track the variants. (Leah Hennel/Alberta Precision Laboratories - image credit)
A specialized diagnostics team at Alberta Precision Laboratories has developed screening tests for variants as SARS-CoV-2 evolves. Starting Thursday, the province will focus surveillance on genome sequencing to track the variants. (Leah Hennel/Alberta Precision Laboratories - image credit)

As the third anniversary of the global pandemic approaches, Alberta is changing the way it tests for COVID-19 variants.

The provincial lab, which had been screening all positive samples for variants, will stop doing that as of Thursday.

Alberta Health Services (AHS) said SARS-CoV-2 surveillance will now rely on genome sequencing — which will continue to be conducted on a subset of positive samples — bringing Alberta in line with other provinces.

"I'm comfortable with this at this point in time," said Dr. Dan Gregson, an infectious disease specialist at the University of Calgary's Cumming School of Medicine.

"They're going to restrict it to a certain percentage of samples and … outbreaks and people who are severely ill —  if people end up in the ICU — to try and pick up anything that might be happening there. I think that's to reduce the cost and the burden on the system, and I think that's very reasonable."

An Alberta Precision Laboratories and public health lab bulletin, shared with health-care providers, said screening tests were introduced early in 2021 in an effort to supplement genome sequencing.

As new variants emerged in the province, new screening tests were developed. But the memo said they could no longer be implemented in a "timely fashion."

According to the memo, no other provinces are using this tracking method.

"The rate at which new sublineages and recombinant lineages are emerging makes it extremely challenging to continue to design and implement new variant screening tests," the bulletin said.

Alberta Precision Laboratories
Alberta Precision Laboratories

The change takes effect Thursday.

In a statement shared with CBC News, AHS said patient care will not be impacted.

"Genome sequencing provides an accurate picture of variant circulation in Alberta and continues to have the ability to detect new emerging variants," spokesperson Kerry Williamson said.

"Genome sequencing provides a full picture of each strain infecting individuals rather than just a few mutations, allowing full genetic characterization and precise lineage determination."

Meanwhile, Gregson said he believes variant screening could be ramped up again if it's needed to make patient care and treatment decisions.

"You don't have to test the whole population to figure out what's going on in the population. You can do a certain percentage of samples, like you would do for election polling," he said.

"And they have wastewater testing in place already, which does test the whole population. And that's a broad brush of what's going on in transmission in the province."