"Recent national surveillance data show that young adults aged 20-39 years of age account for the highest incidence rates across all ages in Canada," Canada's chief public health officer Theresa Tam said in a statement. 

For the week ending July 22, the incidence rate was highest among young men and women aged 20-29 (14.4 and 13.8 cases per 100,000 people respectively), followed by those aged 30-39. 

"Younger Canadians are not invincible" to the disease, Tam warned, noting that it is not only the elderly who are at risk of serious health problems if infected. 

She pointed out that, of the cases of COVID-19 reported to public health last week, 63 percent involved people under 39 years of age, of whom roughly one-third were hospitalized.

There was an average of 485 new cases reported daily across the country last week. 

As Canada continues to lift lockdown restrictions, Tam called on fellow citizens to be cautious and to respect social distancing and hygiene measures.

"In the absence of a vaccine, living with COVID-19 is not without risk," she added. 

According to the latest available figures, Canada has so far recorded some 113,800 cases of the new coronavirus and 8,900 deaths.

Public health guidelines are widely respected in Canada, but even so, several hundred people protested in Quebec City Sunday against the wearing of face masks, which are now compulsory in the French speaking province.