Why Manitoba needs to be more like B.C. if it wants to keep a lid on COVID-19
On the West Coast, the active caseload is dropping; Manitoba needs slower growth to achieve a similar goal
In these early weeks of the COVID-19 pandemic, there's reason for cautious optimism as well as serious concern.
The disease is growing at roughly the same rate in Manitoba as it has in most other Canadian provinces during the initial weeks after they report their 10th case of COVID-19.
This middle-of-the-pack performance suggests Manitoba stands at a precipice.
If government-mandated measures aimed at slowing the spread of the disease prove to be successful, the growth rate for the disease in Manitoba could drop to the point where the health-care system can handle the demands of treating COVID-19 patients.
That same system may struggle, however, if the number of known COVID-19 cases continues to double in Manitoba every four days, which is the growth rate for the disease right now.
"Manitoba is not a lot different from any other jurisdiction in Canada," said Dan Chateau, a community health sciences professor at the University of Manitoba, referring to the once-every-four-days doubling period.
Right now, Manitoba's growth is in line with Ontario, where the pandemic is farther along and the health-care system is starting to struggle to meet the demands of COVID-19 patients.
Chateau says this province may suffer the same fate as Ontario.
"If something doesn't change here in Manitoba, we could expect … in a couple of weeks well over a thousand cases," he said.
In B.C., initial Ontario-like growth has given way to a more gradual rate of increase in the number of COVID-19 cases.
"British Columbia has managed to turn it around and their rate of doubling has really slowed," Chateau said. "They're an important case example to try to point to" as Manitoba works to slow the growth rate here.
The closure of Manitoba schools, restaurants and personal-service businesses such as hair salons, as well as restrictions on large gatherings, may very well accomplish that goal, he said.
"I really hope to see the province kind of take on that bending of the curve that we've seen in B.C. and I think the province did a good job in declaring a state of emergency back on [March] 20th," Chateau said.
He's optimistic the measures could reduce Manitoba's case growth to the point where it only doubles once every seven or 10 days, instead of every four.
But "in two weeks, if we're up at 1,250 cases … it will tell us that we really haven't accomplished much."
On a linear chart like the one above, which shows Manitoba's 194 known cases (as of Saturday), the outbreak appears to start slowly and then balloon quickly, even as the growth rate of the disease remained constant.
On a logarithmic chart, like the one higher up this page, the slope of the line reveals the rate of growth in COVID-19 cases.
A straight diagonal line indicates no change in the growth rate, while a flattening curve toward a horizontal line indicates the growth rate is slowing down.
Tracking COVID-19 this way can reveal whether government measures to slow the spread of the virus — mainly measures to encourage physical distancing and hand-washing — are actually reducing the growth rate.
Active cases vs. total cases
Another measure to watch is something called the active COVID-19 caseload. That's the number of total COVID-19 cases, minus patients who either died or recovered.
In Manitoba, the total caseload was 194 as of Saturday — but that includes two COVID-19-related deaths, and 17 patients who have recovered, so the province's active caseload as of Saturday was 175.
To the health-care system, the number of active COVID-19 cases is more important than the total caseload, since the active cases represent the maximum number of people who could require medical attention at any given time.
In most jurisdictions around the world, roughly 80 per cent of COVID-19 patients either suffer mild symptoms or suffer through disease at home. The rest require some medical attention, while a minority must be hospitalized.
As of Saturday, Manitoba had 10 patients in hospital, including six in intensive care units. This is well within the capacity of the health-care system, even with more than 100 workers isolating at home due to exposure to the disease.
In British Columbia, the number of active cases of COVID-19 stood at 461 on Saturday, a significant drop from a high of 525 on March 26.
That is the result of the slower COVID-19 growth rate on the West Coast: more B.C. patients are recovering every day than are getting diagnosed with the illness.
This means the B.C. health-care system is dealing with no more COVID-19 patients today than it did a week ago — a very encouraging sign this early into the pandemic.
"For the past week or so, B.C. has had a stable number of active cases because of their flattening of the curve, the reduction in the rate of the increase in the number of cases," Chateau said.
"If we can get that to flatten here, maybe we can run with a steady number of active cases that won't overwhelm the requirements and availability of important equipment."
Chief among that vitally important equipment are the ventilators required to keep the most serious COVID-19 patients alive in intensive care units.
Depending on the age and overall health of a given population, anywhere from three to six per cent of the active COVID-19 caseload may require ventilation at any given time.
This bears out right now in Manitoba, where six of the 175 active cases — 3.4 per cent — are receiving intensive care.
Compared to B.C., Manitoba has slightly fewer ventilators per capita. That may be less important to note than the total number of ventilators the province possesses.
That number is 270 at the moment, plus 136 more in surgical suites.
If the demand for ventilators is indeed three to six per cent of COVID-19 patients, then Manitoba must keep its active COVID-19 caseload down below the 4,500 to 9,000 range at any given time (and that assumes, of course, those ventilators aren't needed by non-COVID patients).
Failing to do so would create an Italy-like situation, where doctors are forced to choose which critically ill patients are kept alive on ventilators.
Going the distance on distancing
On one hand, ensuring Manitoba's active caseload remains below 4,500 people at any given time sounds like a reasonable goal, at a time when the active caseload in much larger B.C. is only 461 and dropping.
That said, neither B.C. nor Manitoba will be able to hold the line on the disease if physical distancing measures are relaxed too soon.
"I can't imagine that physical distancing measures will be removed for at least a couple of months," Chateau said.
Manitoba first has to get to a plateau of active cases and remain there until the active caseload begins to decrease significantly, he said.
Otherwise, COVID-19 will just start spreading again, and all the painful economic sacrifices made by Manitobans will be for naught.
"It would be terrible to get a handle on it and think we're safe and start ignoring it," he said.
Chateau envisions a gradual lifting of physical distancing measures, slowly and in stages.
"It has to be incremental in its nature. Are you going to start allowing international travel? Are you going to start allowing interprovincial travel with a quarantine? Are you going to start allowing people to get together in restaurants?" he asked.
"I think the last thing we'll see come back is the sorts of things that we all enjoy, which is large events, like concerts and sporting events with audiences," he said.
"I wouldn't expect to see anything like that before the end of the summer."
In other words, a best-case scenario in Manitoba may involve a summer without festivals and professional football.
It definitely means Manitoba must reach a plateau of active COVID-19 cases at a load below the level where the health-care system runs out of ventilators for the most serious patients — and health-care workers to take care of them.
More Manitobans are expected to die from this disease. But if no patient succumbs solely because there isn't enough capacity in the system, then physical distancing will have done its job.