COVID-19 cases could more than quadruple Manitoba's previous record at the peak of a fourth wave this fall, or drop to zero, depending on vaccinations and how closely health orders are followed.

High vaccine uptake and behavioural changes will play a major role in COVID-19 cases in the fourth wave. Dr. Jazz Atwal, Manitoba's Deputy Public Health Officer, is sharing on Tuesday what fall cases could look like.

"It is hard to predict the future. These scenarios are based on vaccine uptake. What changes between the scenarios is behaviours, and it is about how people interact with each other. It is about practicing the fundimentals," Atwal says.

At its best, Manitoba could see no new cases for months, and at its worst, edging on 2,500 cases per day. The highest number of COVID-19 cases Manitoba has ever seen in its daily count was 603 confirmed cases for May 19, 2021.

Sharing three scenarios, Controlled, Severe, and Extreme, Atwal is unable to say which one Manitoba is more likely to follow. In the past, Manitoba has reached the severe level.

projections last quater of yearCOVID-19 projections for the fourth wave include August 17 as an arbitrary start date. (Province of Manitoba)

Using 290 parameters, the Province of Manitoba is giving the province a picture as to what the fourth wave's curve could look like.

"These parameters include population demographics, peoples behaviour, disease spread, public health measures, laboratory testing, contact tracing, immunizations, different variants of the virus, VOCs and non-VOCs (variants of concern) and many other factors."

How well Manitobans follow the health orders will play a role in the scenarios along with vaccinations.

"When we re-implement restrictions it's for a reason. And we're facing this fourth wave, and you can see the early effects of this 4th wave, in other jurisdictions and that's coming to Manitoba. So we're doing this preemptively and for very clear reasons," Dr. Brent Roussin says in an earlier press conference, addressing pandemic fatigue.

The influenza season will overlap with Manitoba's fourth wave and other provinces will potentially be experiencing high intensive care volumes at the same time. Previously, Manitoba sent COVID-19 patients to other provinces, such as Alberta, Saskatchewan, and Ontario, after running out of room due to lack of staffing.

icu projectionsA total 246 Manitobans were admitted into intensive care in May. (Province of Manitoba)

Close to 250 Manitobans were admitted to intensive care in May, overfilling Manitoban hospitals. Between May 18 to June 9, 57 Manitobans were transferred out of province for care.

Atwal could not say how intensive care units will manage to keep up with the severe and extreme scenarios, saying that is what they are trying to avoid.

"We are keeping a real close eye on this. We are going to be announcing some messaging and orders over the next several days."

The province did not have estimated COVID-19 related death tolls available.

In the upcoming days, guidance will be coming from the province. Atwal says this will help "control and mitigate" cases and the acute care system.