OTTAWA -- Canada’s top public health officials are preparing for a "peak" of COVID-19 cases in the fall and localized outbreaks until at least January 2022, new modelling data shows.

The report underlines that officials are aiming for a "slow burn" scenario, "keeping case rates low and within the health and public health system’s capacity to manage," but are preparing for a worst-case scenario which shows a surge of cases when flu season approaches and then ongoing "peaks and valleys" for the next several years.

Chief Public Health Officer Dr. Theresa Tam said this projection is subject to change depending on Canadians’ behaviour.

"Everything is sort of in our hands, so the sort of day-by-day, week-by-week monitoring of how well we control things right now will sort of determine the actual outcome. So even the short-term forecasts are subject fluctuations that you’re seeing now so really the take home message is that the fate is still within our hands and what we do now will influence the probability, if you like, of that fall peak," she said during a press briefing in Ottawa on Friday.

She said she is encouraging hospitals and other health-care facilities to implement emergency plans in case of a fall spike, potentially even greater than the first wave of cases in Canada.

"This isn’t taking into account the fact that the most vulnerable populations, including long-term care and seniors, is where a lot of efforts have to be pulled together. Having learned what we learned in that initial wave, we don’t want to exceed the capacity of those parts of society," said Tam.

The modelling also shows the rate of infections has hit young adults between the ages of 20 and 39 the hardest since early July, reflecting regional trends reported over the past several weeks.

While the severity of illness among this age group remains low, Tam said young people are not "immune" to infection and more spikes in cases are likely if Canadians don’t remain vigilant.

Deputy Public Health Officer Dr. Howard Njoo partially attributed the trend to the reopening of certain facilities like bars and restaurants and general crowded indoor settings, where physical distancing isn’t possible.

"There’s always the same challenge across the country in my opinion, young adults," he said, speaking in French. "It’s hard with summer I think, everyone has got pandemic fatigue and are tired of the public health measures, and since it’s summer we want to take advantage of the season which is so short here in Canada."

He pointed to recent examples in British Columbia where there’s a disproportionate increase of cases among young adults since the easing of social gathering restrictions.

The province’s Public Health Officer Dr. Bonnie Henry cautioned on Thursday that numbers could reach or soon surpass the number of cases back in March and April at the height of the outbreak.

"It's a very small proportion of the population that are doing things that are causing some of the spread that we're seeing. The vast majority of us are weathering this together and that's what we need to continue to do," she told reporters.

PREPARING FOR THE FALL

The colliding of the influenza season and COVID-19 will cause the fall surge of new cases that public health is preparing for and Tam said it’s critical that Canada keeps numbers low enough to not exceed the health-care system’s capacity.

"What we know, based on what we learned from other countries and cities that had a devastating impact in that initial wave is if you exceeded that capacity, the mortality goes up really, really high," she said.

Njoo said Canada is using the summer months to increase its stockpiling of personal protective equipment, ventilators, and other supplies. At the same time, Canadians should expect to see more government communication and campaign materials about the importance of influenza vaccination, he said.

"It’s still early, but I would strongly encourage everyone to get their flu shot when it does become available. I certainly get my flu shot every year, so does Dr. Tam," he said. "Please consider getting your flu shot this fall."

While Tam and her team are preparing for a scenario "several times worse" than the first wave, they are reassured Canada is more prepared than in March to handle another surge.

COVID ALERT

Both doctors encouraged the use of the government’s new exposure notification app, dubbed COVID Alert, that has already garnered 1.9 million downloads.

"That’s a pretty good result since the start of the pilot. I would encourage those who live with their phones, the younger adults, to download this particularly as we’ve seen with the epidemiology, this age group is more prone to going to certain social situations, pubs, nightclubs, whatever, where you might not know every contact in that vicinity," said Tam.

Health Canada launched the app on July 31 in partnership with the province of Ontario, but will soon roll it out nationwide.