TORONTO -- Doctors across Canada are warning that they are seeing an increase in young Canadians being hospitalized with more severe complications from COVID-19.

Infectious disease specialist Dr. Abdu Sharkawy previously told CTV's Your Morning that the third wave of the COVID-19 pandemic is infecting those under the age of 40 more, largely due to increased circulation of more transmissible variants.

"We're seeing younger, healthier people develop this disease because they're unvaccinated and these variants are just likely to hit them," Sharkawy said on Wednesday.

"You don't know where you're going to end up on that dial and unfortunately, we're seeing some pretty tragic consequences of that," he added.

According to new modelling from the Public Health Agency of Canada, Canada is on track to see a "strong resurgence" of COVID-19 cases across the country if these variants continue to spread and become more commonplace, and if public health measures remain at current levels.

The new long-range projections, released on Friday, show that the highest incidences of COVID-19 are currently being experienced in British Columbia, Saskatchewan, Manitoba, and parts of Ontario, while the overall incidence rates are highest among young adults aged 20 to 39 and have declined among older Canadians.

Canada’s Chief Public Health Officer Dr. Theresa Tam said that as of Friday, over 7,100 variant cases have been reported across Canada, with the B.1.1.7 variant accounting for more than 90 per cent of those infections.

During a press conference, Tam said that coronavirus variants may be impacting younger Canadians more than older generations because many seniors and vulnerable groups have already been vaccinated.

"…That circulation of COVID-19 in younger, more mobile and socially connected adults presents an ongoing risk for spread into high-risk populations and settings, and continuing transmission in the community," Tam said.

She noted that it is important to remember "although severe illness is less common in younger age groups, serious or prolonged illness can occur at any age."

Dr. Raywat Deonandan, an epidemiologist at the University of Ottawa, told CTV News Channel on Friday that the variants have almost created "a brand new pandemic."

"This is not the same disease we've been dealing with for the past year. The new variants are a dire threat, they're… more transmissible and lethal so our old mitigation strategies might not be sufficient," Deonandan explained.

However, he reiterated that COVID-19 vaccines will still work against most of these variants.

"Our best bet to get out of this quickly is to restrain ourselves from unnecessary exposure and to ramp up vaccination as much as we can," Deonandan said.

He added that vaccine hesitancy as well as waiting for a certain vaccine instead of taking the one that is first offered increases the risks these variants pose to individuals and communities.

"If we have available doses and people [aren't] stepping up to receive them within their time, that slows down the overall process and extends the suffering of the population unnecessarily," Deonandan said.

"Every day you spend unvaccinated is a day that you're at risk of getting COVID and therefore at risk of being hospitalized, at risk of long COVID, and at risk of dying," he added.

Deonandan said Canada will reach herd immunity and return to normal faster, and likely stifle out most of the variants of concern, if people get vaccinated as soon as possible and maintain current public heath restrictions.

YOUNG VARIANT CASES A CONCERN ACROSS THE COUNTRY

Toronto emergency room physician Dr. Kashif Pirzada recently took to social media to share images of the lungs of COVID-19 patients to highlight the toll COVID-19 is taking on young people.

In one set of images, a set of healthy lungs from a 30 year old are seen next to a pair from a 35-year-old teacher who tested positive for the B.1.1.7 variant, which was first detected in the United Kingdom.

The infected set of lungs appear to be entirely covered in a white shadow. Pirzada previously told CTV Toronto this is what the lungs look like when they are filled with fluid, making it extremely difficult to breathe.

"All of us are kind of shocked how young these patients are," Pirzada said. "What worries us is people are unaware of this. People are taking risks, they are going into crowded settings, but they have no idea how bad [COVID-19] is getting."

Dr. Daniel Kalla, head of the emergency department at St. Paul's Hospital in downtown Vancouver, said at a press conference on Monday that scans showing fluid-filled lungs are familiar to every doctor in the country treating COVID-19 patients.

Kalla said it is "vitally important" that younger people understand these risks associated with the coronavirus can also affect them.

"We've had a couple cases at St Paul's with people who quite literally were fine the night before, who are then not only put on life support, but put on bypass because their lungs don't ... work anymore, and it happens so quickly," Kalla explained.

While he acknowledges that young, healthy people who contract COVID-19 typically recover, Kalla says the novel coronavirus remains a "very unpredictable virus."

"I know there's this false sense of security because most young, healthy people do fine with it, but a certain percentage is going to get incredibly sick and some of them are going to die," Kalla said.

"You can't just rely on the fact that you were healthy before you had COVID," he added.

B.C.'s top doctor said on Thursday she is concerned that the spread of variants, especially the B.1.1.7 variant, could be bringing more severe illness to all ages.

"We've now seen data particularly from the U.K., but some other countries as well, that shows that it can have increased severity of illness in younger people and across the age spectrum," Dr. Bonnie Henry said during a news conference.

In an interview with CTV Regina, Saskatchewan's Chief Medical Officer Dr. Susan Shaw warned that becoming sick with a coronavirus variant can bring different and more severe complications than that of the original virus.

"We're definitely seeing that younger people are as susceptible to the COVID virus as anyone else, and that when people get sick with COVID -- particularly with a variant -- it's a more serious illness that can cause more harm," Shaw said.

Shaw stressed the importance of young people continuing to follow public health restrictions so as not to overwhelm the health-care system.

"I'm really worried because if young people are becoming ill, and our hospitals are going to be struggling to help manage and take care of everybody because of the increased spread of the virus, we're all in a difficult situation," Shaw said.

With files from CTVNews.ca's Rachel Aiello, CTV News Toronto, CTV News Vancouver and CTV News Regina