Calgary

Albertans asked to 'assess their own risk' for COVID-19. Here's how

With Alberta's health minister now asking people to assess their own individual risk for COVID-19 infection, here's a guide on how to figure that out.

Which COVID-19 indicators are useful, and which can be ignored with less information coming out

Wastewater data gives the most advanced view of where viral infections are heading in a city. (Rob Easton/CBC)

COVID-19 wastewater data around Alberta show viral transmission is again on the upswing in the province. That means we could be entering yet another wave of the pandemic, driven this time by the Omicron subvariant known as BA.2, similar to what has been seen in Europe and parts of the United States.

But Alberta Health Minister Jason Copping said at his weekly COVID-19 press conference Wednesday the province is going to take a "wait and see" approach to implementing public health measures not already in place.

"We ask Albertans to assess their own risk," he said, "understand what their level of comfort is, and then be guiding accordingly, as well as go get rapid test... If you haven't gotten all your booster shots that you're eligible for, please do so."

As Albertans consider their individual risk for COVID-19, there remains a significant population who are considered immunocompromised and at higher risk of hospitalization and death if they contract COVID-19.

Alberta Health is also only releasing COVID-19 numbers on a weekly basis now, so how does one navigate the indicators and determine one's own risk?

The indicators

There are a number of indicators that have varying degrees of usefulness.

COVID-19 began with mounting case numbers that eventually overran many jurisdictions' capacity to test for it. With the arrival of the highly transmissible Omicron variant and limiting of Alberta Health PCR tests to people in high risk settings like health and long-term care, we have returned to undercounting in official numbers.

The Y axis denotes the number of SARS-CoV2 RNA particles detected per millilitre of wastewater. This chart should only be interpreted as a measure of progress against itself and not used to compare with other cities or measurement sites. (Rob Easton/CBC)
The Y axis denotes the number of SARS-CoV2 RNA particles detected in each sample. The numbers show the first number multiplied by 10 to the power of the small number above. For example 2.1 x 10¹⁵ written out in full is 2,100,000,000,000,000 or 2.1 quadrillion RNA particles detected. (Rob Easton/CBC)

Wastewater data has been filling gaps, giving us a bird's-eye view of the virus in 20 different Alberta communities. Some of those communities, like Calgary or Edmonton, are even broken down by district.

This is the best indicator for individuals to gauge whether COVID-19 is increasing or decreasing in their community, according to according to Dr. Craig Jenne, an associate professor at the University of Calgary department of microbiology, immunology, and infectious diseases. 

It can also give a warning to those who may want to reconsider their prevention approaches as the trend increases, he says, but it doesn't provide all the risk details.

"Although wastewater is a very useful tool, and we can get community or city level data, it does not provide us the granular information about which, for example, age groups are experiencing the most viral transmission, which activities or which events pose a greater risk for viral transmission, we simply get a 30,000 foot view of how much virus is within a given community," Jenne said.

The key to reading wastewater data is by looking at the trend line. If there are three readings in a row with increasing or decreasing numbers, it can be said COVID-19 levels in the community are moving in one direction or the other, according to Dr. Michael Parkins, one of the research leads on the wastewater monitoring project in Calgary.

It is also a leading indicator and with past waves has preceded people showing COVID symptoms and outward signs of the disease by as much as six days, added Parkins, who is also an associate professor at the University of Calgary's Cumming School of Medicine and section chief of infectious diseases for Alberta Health Services.

Aside from wastewater, Alberta Health still offers data on its interactive data app on the COVID-19 portal, which does offer more granular information about risk factors such as age, comorbidities and the like.

Test positivity rates are another relative indicator that can show how the province is doing as a whole. CBC News in Calgary previously republished the Alberta test positivity rate in Alberta in our daily "Need to know" file and will continue to do so less frequently as the data is only released on a weekly basis.

Hospitalization and ICU numbers don't suffer from the limited testing problem because hospitals are in the high priority group for testing. However, the hospital numbers also include people in with COVID-19 as well as those who are there for COVID-19.

If you are someone considered at risk of a negative outcome, hospitalizations is not the best indicator to look at because by the time hospitalizations are up, it is already too late, says Jenne.

"It likely is the situation that the virus has already been at elevated levels in the community for several weeks before those hospitalizations change. Likewise, ICU admissions are even more delayed," Jenne says.


Who's at risk

The number of people who are considered immunocompromised is remarkably high, according to Dr. Dan Gregson, an infectious diseases specialist, microbiologist and associate professor of the Cumming School of Medicine and University of Calgary, but many fit into several broad categories with varying degrees of risk.

"There's a gradation in terms of, of what people get for their for their treatment. And even with a transplant patients, usually earlier on, you're on a lot of immunosuppression and that's where it gets tapered back as as, as time goes by," he says.

Gregson says those who are vaccinated, boosted and don't have any of the other risk factors are likely to experience a COVID-19 infection as a bad cold. Those who have risk factors, it could be very different.

Alberta Health has recently made fourth doses of COVID-19 vaccine available to those who broadly fit into the immunocompromised category. Here are the current criteria for fourth doses in the province:

  • Recipients of chimeric antigen receptor (CAR)-T-cell therapy
  • Moderate to severe primary immunodeficiency (for example, DiGeorge syndrome, Wiskott-Aldrich syndrome)
  • Advanced untreated HIV infection or acquired immunodeficiency syndrome (AIDS)
  • Immunosuppressive therapies (for example, anti-B cell therapies, high-dose systemic corticosteroids, alkylating agents, antimetabolites, or tumor-necrosis factor (TNF) inhibitors and other biologic agents)
  • Transplant recipients, including solid organ and hematopoietic stem cell transplants
  • Chronic kidney disease receiving regular dialysis
  • Receiving active cancer treatment (chemotherapy, immunotherapy or targeted therapies), excluding those receiving only hormonal therapy, radiation therapy or surgery
  • Taking certain medications for autoimmune diseases including rituximab, ocrelizumab, ofatumumab and methotrexate

Assessing one's own risk is also a matter of who you are in contact with. If you are a regular contact of someone who immunocompromised, both Jenne and Gregson say you will want to consider extra precautions.

Precautions

Mask wearing, physical distance, avoiding large crowds and enclosed spaces, deciding not to attend events: These are all the measures many have followed since the start of the pandemic and they continue to be effective, but Gregson says there is one measure that helps the most.

"The first recommendation I would have is that you get your COVID immunizations up to date. So that's for most of us who have had the second dose, get your third dose, and for people are immunocompromised, get your fourth dose," he said.

Immunocompromised people and their contacts could also consider rapid tests as a regular practice before meetings as another way of reducing transmission.

Gregson says as wastewater numbers go up, people will want to consider masking depending on their comfort levels, if not for yourself, then for those who are in the higher risk category but still have to go out.

He also recommends looking at the behaviour of people you're around in public. If the staff at a coffee shop is wearing a mask, it makes sense to wear one too because everyone there might be wearing one for a reason.

"Think about the other people in the room and if you're concerned to put a mask on," he says.

ABOUT THE AUTHOR

Rob Easton

Data Journalist

Rob Easton is a data journalist for CBC News in Calgary. His previous beats include data visualization and graphics, LGBT2SI+ and refugee stories. He has also directed documentaries, reality TV and story produced for CBC Radio. You can reach him at Rob.Easton@cbc.ca.

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