University of Toronto researchers have found more evidence that Ontario's physical distancing measures are having the desired effect. But the newest models suggest that without more testing and tracing, an increase to more than 50 per cent of pre-COVID-19 physical contact would quickly overwhelm the province's intensive care units.
The model is a worst-case scenario that shows how quickly Ontario would lose ground if people stop physically distancing as the province continues to re-open services and businesses.
The research was published this week in the journal Annals of Internal Medicine.
"The point of this research is to show how effective physical distancing is, but also how tenuous its effect is," says Ashleigh Tuite, lead author of the study and an assistant professor at the Dalla Lana School of Public Health. "Will people continue to practise hand hygiene, distancing and masking?"
In the model, 50 per cent means returning to half the typical interactions a person might have on a typical day before the pandemic arrived. This scenario assumes Ontario will continue to test and trace cases at the current level, even as more of the province opens up for business.
The authors hope that will not stay the case.
"This really is a call for ramping up testing and contact tracing," says Tuite. "If we had that in place, we could think about relaxing distancing more. This would allow us to find local hotspots more quickly and break ongoing chains of transmission."
Tuite says she was encouraged by the recent outcry over crowding in Toronto's Trinity Bellwoods Park on a sunny Saturday because it shows Torontonians are still strongly committed to distancing.
The results are similar to previous models developed by the researchers, which include Dalla Lana Professor David Fisman and Associate Professor Amy Greer. But it's updated with the latest evidence on the percentage of patients who are asymptomatic, the length of time people are infected before symptoms occur and the percentage of people getting tested and traced.
