Almost half of Canada’s COVID-19 cases are caused by spread in the community from an unknown source, and experts say that signals there could be a silent epidemic happening across the country.
Almost half of Canada’s COVID-19 cases are caused by spread in the community from an unknown source, and experts say that signals there could be a silent epidemic happening across the country.
Of the 1,044 cases that the Public Health Agency of Canada has provided epidemiological data on as of Monday, 48 per cent are a result of infection from community transmission, while 42 per cent are tied to travel and seven per cent are linked to close contact with a traveller who tested positive.
Community transmission is the spread of an illness with no known link to travel or previously confirmed cases, which suggests a growing number of cases are likely going unreported across the country.
“It’s about 50 per cent of travellers versus those who are acquiring it in the community,” Dr. Theresa Tam, Canada’s chief public health officer, said Tuesday.
“That is a fundamental shift in our epidemiology.”
Jason Kindrachuk, an assistant professor of viral pathogenesis at the University of Manitoba and Canada Research Chair of emerging viruses, said that shift makes it more difficult to slow the spread of the coronavirus in Canada.
“If a virus is now spreading in the community, what that means is that we don’t have a really good ability to be able to monitor where that virus is, who it’s going to and who that person has contacted,” he said.
“You don’t know where the virus is at any particular moment in time, and now what you have is basically the potential for that person to pass it on to a much larger group of people.”
Kindrachuk said community transmission is particularly challenging because the virus doesn’t produce symptoms in everyone it infects.
“They’re not may