Ontarians might balk at school closures, cancelled sports events, and work-from-home orders at this stage of the COVID-19 outbreak. But University of Toronto-led research suggests that major “social distancing” measures may be necessary to stop the infectious disease from swamping the province’s health care system with critically ill patients — a disaster rapidly unfolding in northern Italy.

The researchers used mathematical modelling to compare how different types of interventions would affect the epidemic if the new coronavirus begins to spread locally. Though there has been no evidence yet of significant “community transmission” in Ontario, the World Health Organization declared a pandemic Wednesday because of the scope of the virus’s global spread.

The model suggests that in a scenario with limited containment efforts, the number of patients in hospital intensive care units (ICUs) could eventually rise to more than 32,000 at the peak of the epidemic. Ontario has roughly 1,700 ICU beds, most of which are already occupied by the province’s sickest patients. This scenario is highly unlikely given Ontario’s response so far, but represents a baseline to compare escalating levels of interventions.

Of the interventions they tested, only the widespread, early adoption of major social distancing measures — a massive reduction in person-to-person contacts, one that would require both school closures and remote work for adults — would bring the number of patients in intensive care to a manageable number of around 200. Half-measures still result in scenarios with many times more critically ill patients than available critical care beds.

“Models allow us to look ahead, and look around the corner,” said David Fisman, an epidemiologist and professor at U of T’s Dalla Lana School of Public Health, who was a principal investigator on the modelling research.

“We don’t want to wind up like Italy, with our hospitals collapsing. For people to understand how bad this can be, they need to see a no-intervention scenario. They’re not going to see that in the real world, because we’re going to do stuff about it.”

Approximately 80 per cent of COVID-19 cases are mild or moderate, with many patients able to recover at home — as nearly all cases diagnosed in Ontario so far have done.

But the remaining 20 per cent who suffer severe symptoms, especially those who require the specialized staff and equipment available in critical care units, represent the most acute risk to the health care system. If enough people become infected, that small percentage can result in the sort of deluge that Italy is experiencing right now.

Less than three weeks ago, Italy had nine confirmed COVID-19 cases and no deaths. Today, the country has reported more than 12,000 cases and more than 800 deaths. Desperate pleas to take the outbreak seriously from doctors in Lombardy, the wealthy region most affected, have circulated online.

A guidance document issued by an Italian physicians’ association on Wednesday cited the “enormous imbalance” between the needs of COVID-19 patients and availability of intensive care resources as a reason to discuss wartime-like triaging of patients: those likeliest to survive may have be prioritized above others.

Meanwhile, South Korea, Singapore, and China have all seen a sharp rise of cases level off after aggressive public health interventions. This levelling is known as “flattening the epidemic curve”: if the same number of cases are spread out over a longer period, the health care system is better equipped to treat each one, with better outcomes for all — including all the patients who wind up in acute care for other reasons, like strokes, traumatic injuries, birth complications and severe seasonal flu.

A pre-print study published Wednesday — research that has not yet been peer-reviewed — suggested that the outbreak in China could have been 67 times worse if not for “nonpharmaceutical interventions,” including extreme social distancing and early detection of cases. Daily cases counts in China have been steadily declining.

Restricting movement has severe social and economic costs, both for individuals and families — especially those who are precariously employed, and whose employers don’t offer paid sick days — and for countries as a whole.

In addition to severely limiting travel throughout the country, Italy announced Wednesday it was shuttering all businesses except pharmacies and grocery stores, a move some experts said came too late in the outbreak. They said less severe measures implemented earlier would have been more effective.

“It’s disruptive and expensive. The paradox is that nobody wants to do it when things aren’t that bad yet,” says Fisman.

“To get political will, we have to show people what happens without these measures, and that’s why the model is so important. It allows us to see the alternate versions of reality.”

Kevin Smith, president and CEO of Toronto’s University Health Network, said hospitals and health care leaders in Ontario are carefully watching the global response to the COVID-19 pandemic, including the outbreak in Northern Italy — and that there are good reasons to think Ontario will avoid Italy’s fate.

“The good news in Canada is that activities to date seem to have been very effective in limiting community spread of the virus,” said Smith, who is hospital lead for the Toronto region’s response to critical care needs.

“And if we do see community spread, and if the numbers of cases increase, we do have a critical care response process in place.”

Smith said he is optimistic that Ontario hospitals will not be overwhelmed by a surge of acutely ill patients with COVID-19. Ontario, and particularly the Toronto region, is drawing on past experience with SARS and is now more prepared for a pandemic illness, he said.

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“Isolating people who have flu-like symptoms when they arrive in emergency rooms doesn’t appear to have happened in Europe, early on,” Smith said. “We are immediately isolating those people into an environment where they are unlikely to infect others.”

Infectious disease modelling uses existing data and assumptions about how an outbreak will behave to predict what might happen in the future. Some of those assumptions may turn out to be incorrect, and the spread of COVID-19 here could turn out to be much milder even without massive interventions.

It’s possible that Ontario will never experience the level of community transmission that the model estimates — just as it’s also possible that the province is on the cusp of a wider outbreak.

“From a public health perspective, that’s always the challenge,” said Amy Greer, Canada research chair in population disease modelling at the University of Guelph, who contributed research to the project.

“If we do a really good job, people say, ‘Well you were overreacting, because nothing happened.’”