Latest Manitoba modelling contains limited wastewater data

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This article was published 14/02/2022 (1345 days ago), so information in it may no longer be current.

As Manitoba lifts some public health restrictions, experts are concerned about a lack of data on how undoing capacity limits, mask mandates and vaccine-card requirements are expected to affect the health-care system.

In its latest round of modelling, released late afternoon Feb. 11, the provincial government charts declines in COVID-19 case counts, hospitalizations, ICU admissions and deaths.

For the first time, the province released limited wastewater surveillance data, showing the detection of COVID-19 in some areas of Winnipeg peaked between late December 2021 and Jan. 1, and again in mid-January, before continuing to rise and fall.

The published data only shows a snapshot of time between late December and Feb. 1, so it’s not enough to determine lasting trends.

The models show a “decreasing trajectory,” as the charts indicate, but they only serve as a reflection of the current COVID-19 situation. They don’t contain projections about the impact of lifting restrictions, epidemiologists say.

Winnipeg epidemiologist Cynthia Carr said while the addition of the wastewater data is a positive step, it needs to be monitored over the long term. The province hasn’t published any comparable past wastewater surveillance figures, so it’s not useful as a way to look at how COVID-19 transmission has changed in the long term, she said.

As well, Carr said, it’s important to assess the future impact of lifting the province’s public health restrictions.

“We need to look at our indicator matrix and say, with these new changes in… mobility, masks, interaction potential, reduction in perception of urgency around getting vaccinated, what do we think the impact may be in the number of new cases?”

The models should include the potential positive effects of increasing supply of out-of-hospital COVID-19 treatments and booster-shot uptake, Carr added.

In an emailed statement, Souradet Shaw, a social epidemiologist at the University of Manitoba, agreed long-term wastewater data would be helpful — as would future projections that explain the decision to lift restrictions.

“The mathematical modelling is a bit on the sparse side — it is one thing to project cases are declining, based on what the trends were at the time of modelling — so, basically, this is how the wave will behave, all else being equal. But the real power in mathematical modelling lies in being able to project future scenarios,” he wrote.

“Modelling out these types of scenarios, and answering these types of questions, I would think would be crucial for building out the evidence base for policy planning. As well, presenting results of these scenarios to the public would communicate how this type of evidence might be used to influence decision-making, in a transparent and honest manner.”

On Monday, Manitoba recorded 19 additional COVID-19 pandemic deaths, as well as 23 fewer hospitalized patients, since Feb. 11.

The province’s models show the drop in hospitalizations is not simply because some patients have died. They say new deaths decreased by nearly 46 per cent over a one-week period earlier this month.

The province also stated Monday hospitalizations and ICU admissions each dropped by about 12 per cent over the past week.

katie.may@freepress.mb.ca