Postmedia analysis of Statistics Canada data released on Monday shows that of the 3,093 cases from January 15 to March 27, people aged 20 to 39 accounted for almost one-third of all coronavirus positive cases in the country.
Those between the ages of 50 and 59 accounted for almost one fifth of the 3,000 positive cases, while those aged 40 to 49 and 60 to 69 years represented about 16% of the country’s cases.
About 51% of all cases were males and 48% were females, one percent of which were not reported. Men were overrepresented in the 40 to 49 age group, but otherwise there were few differences between cases between men and women.
The data represent only a fraction of the more than 10,000 confirmed cases of COVID-19 in the country, and experts warn that the figures do not paint a full picture of the spread of the virus.
“It is very difficult to infer what is going on in the rest of the population,” said Caroline Colijin, infectious disease modeler and professor of mathematics at Simon Fraser University.
She said there are good reasons to focus testing on healthcare workers, but that a broader testing strategy that matches the makeup of the population would be needed to better understand the spread of the virus.
Young health workers could also contribute to the majority of those under the age of 40 who test positive, said Dr. Anna Banerji to the National Post.
“There is a bias in the numbers,” said the professor from the University of Toronto.
Since health workers are considered high-risk populations, health authorities have concentrated the limited supply of screening kits on this group.
Dr. Jeff Kwong, also at the University of Toronto, pointed out that, in addition to the age group for 20 to 39 year olds being larger than other age groups, travelers in this age group may represent the greatest number of positive cases.
During the first two weeks of March, the number of cases reported daily, both in the community and in travel, increased in tandem, but by the middle of the month, new travel-related cases had started to decrease.
BEFORE CHRIST. health officials began urging residents to avoid all non-essential international travel on March 12. The federal government followed suit the next day and on March 16, the government effectively closed the border to international flights. By then, the number of community transmission cases reported every day had already started to exceed travel-related cases.
The data also shows a day before the federal government closed borders to international flights on March 16, cases of community transmission outstripped travel-related cases.
On March 19, the day after the Canada-US border was closed to all non-essential travel, there were 68 new travel-related COVID-19 cases – and 148 new cases of community spread.
The government has stopped almost all travel, said Dr. Banerji, and travel-related transmission has decreased. But at that time, the virus was already in the community.