New models show how many COVID-19 cases could come into Ontario if border reopens
TORONTO -- As the United States continues to grapple with controlling the spread of COVID-19, new modelling shows how many infected people may arrive at the Canada-U.S. border in Ontario each day.
Ashleigh Tuite, an epidemiologist at the University of Toronto, analyzed data that shows how many infected people could cross the border into Ontario daily, depending on the varying number of travellers and the current rate of infection per capita in the United States.
Tuite estimates that the number of people crossing into Ontario from the United States is currently between 1,000 and 5,000 per day. The border is currently closed to non-essential travellers but there are some exceptions for travel that's deemed essential.
On Sunday, the United States recorded nearly 65,000 new COVID-19 cases. According to Tuite's modelling, if 1,000 people crossed the border yesterday that means statistically between one and two people who entered Ontario would be infected with COVID-19.
If the border was open and 25,000 people crossed into Ontario, that number would rise to anywhere between 30 and 44 cases per day based on the current rate of infection in the United States.
"It's a simple mathematical model," Tuite said. "Based on what we know right now in terms of the epidemiology, probabilistically we can try and quantify the number of people that we'd expect to see with COVID-19."
Tuite said the models shouldn’t be considered completely accurate, but they may help provide an estimate of what the province could expect if border conditions are eased.
She said that mandatory self-isolation requirements in Canada are vital to catch some of the imported cases, but it’s not necessarily enough.
"In theory, we should be catching most of those cases, but it’s not a given that everyone's going to adhere to that," Tuite said.
Tuite said that this kind of modelling analysis as a "risk calculation" when deciding whether to open the border, something she believes won’t be possible for a long time.
"I don't think there is a way," Tuite said. "Unless you had really strict quarantine happening in terms of enforcement."
The Canada-U.S. border closure was extended earlier this month and will remain shut until at least Aug. 21.
Infectious disease specialist Dr. Abdu Sharkawy told CTV News Toronto earlier this month that reopening the border to non-essential travel anytime soon would likely lead to a resurgence in cases in Canada.
"It absolutely terrifies me to think of the prospect of any sort of easing of restrictions that could allow greater travel between Canada and the United States," he said.
The United States is leading the world in COVID-19 cases as it nears the 4.5 million mark, while Canada has just over 114,000. In Ontario, there have been about 38,000 confirmed COVID-19 cases, while in New York, which Ontario shares a border with, there have been 416,000.
"I think if you look around the world at other countries that have successfully flattened the curve, a lot of resurgent cases have been a direct result of travel restrictions being eased," Sharkawy said.
"Border control and travel restrictions are a very key element in keeping your particular geographical area safe."
Ontario Premier Doug Ford said in June that he believes reopening the borders too early could spark a second wave of COVID-19.
"I know it's inevitable … I just don't think we are ready right now," Ford said. "Believe me, I love the Americans, make no mistake about it, but not when their COVID cases are just spiking right now and I’m just not in favour."