More than half of imported variants came from U.S.

Europe, India also key sources, study finds

It has been controversially labelled the “China virus,” but new research suggests Canada's COVID-19 epidemic might be better nicknamed the America virus.

More than half the imported variants of the pathogen that led to outbreaks in this country likely came from the United States, with Russia, India, Italy and the U.K. following well back as sources of imported virus, scientists from B.C., Ontario and Arizona concluded.

Virus arriving directly from China — where the pandemic is believed to have originated — accounts for relatively little transmission of COVID-19 here, they suggested.

The newly posted study was made possible by a remarkable international database of DNA sequences of SARS-COV-2, a resource that's letting scientists track at the genetic level how and where the pandemic is spreading.

The Canadian researchers say importation of virus slowed somewhat after international travel restrictions were imposed in March 2020, but outbreak-causing arrivals continued throughout the year.

“We are so interlinked with other countries and between provinces,” said Angela Mclaughlin, the University of British Columbia doctoral student who co-authored the paper with supervisor Dr. Jeff Joy and others.

“People have family to visit, other reasons to travel," she said. "This just highlights that each one of those actions is a probabilistic event where the virus could be transmitted. It's incredible the extent to which it has done that.”

She and colleagues advocate more stringent actions to keep the pathogen out, such as the 14-day hotel quarantines on international travellers imposed by Australia and New Zealand.