OTTAWA -- Prime Minister Justin Trudeau says that in some parts of the country the COVID-19 second wave has already begun, but Canadians have the power to flatten the curve again, in his evening address to the nation from his West Block office.

"In our four biggest provinces, the second wave isn’t just starting, it’s already underway," said Trudeau, of the current outbreaks in British Columbia, Alberta, Ontario and Quebec. "We’re on the brink of a fall that could be much worse than the spring."

COVID-19 cases have jumped nationally, from about 300 cases per day in mid-August to 1,248 on Tuesday, prompting Chief Public Health Officer Dr. Theresa Tam to implore Canadians and public health policy-makers to redouble infection prevention efforts now, or face a "very sharp and intense peak" in new COVID-19 cases that would likely lead to a return of national lockdowns.

"I know this isn’t the news that any of us wanted to hear. And we can’t change today’s numbers or even tomorrow’s -- those were already decided by what we did, or didn’t do, two weeks ago. But what we can change is where we are in October, and into the winter,” Trudeau said.

He went on to say that it’s likely Canadians won’t be gathering for Thanksgiving, but that “we still have a shot at Christmas."

"Together, we have the power to get this second wave under control,” he said.

Trudeau implored Canadians to wear masks in public, get the flu shot this fall, and download the government's COVID Alert app that notifies users when they have come into contact with someone who has tested positive for the virus.

"This is the time for all of us as Canadians, to do our part for our country, as government does its part for you," he said.

Responding to Trudeau’s declaration of a second wave, CTV Infectious Disease Specialist Dr. Abdu Sharkawy said that he thinks we’re “very much there.”

“We have seen that the numbers are rising disproportionate to the number of tests that are being done, and we've seen a consistent trend of community transmission that has been uncontrolled now for some time. And it's evidenced by people in my emergency room and in my ICU,” Dr. Sharkawy said, adding that addressing the current testing backlogs and delays seen in some regions need to be rectified as soon as possible if Canada is to get this new spike in cases under control.

Trudeau's national remarks came just a few hours after Gov. Gen. Julie Payette delivered the minority government’s speech from the throne in which the federal Liberals promised to keep financially supporting Canadians through what’s shaping up to be a fall resurgence of the virus, while repairing the inequalities the pandemic has exposed.

The prime minister also took this opportunity to personally pitch his government’s economic and social response and rebuilding plan to Canadians. According to his prepared remarks shared with reporters in advance of his address, Trudeau also touched on the measures his government has and will continue to take to aid out of work and ill Canadians in the months ahead.

"The federal government will have your back, whatever it takes, to help you get through this crisis," referencing the 9 million people who used the Canada Emergency Response Benefit which is now being transitioned into a modified Employment Insurance program, as well as the employees who were hired back because their employers accessed the emergency wage subsidy program that is now being extended until next summer.

This evening address is different than the more than 80 morning addresses to the nation that the prime minister held between mid-March and late June, where day after day he unveiled billions of dollars in aid to Canadians out of work, struggling businesses, and to procure personal protective equipment, test kits, and vaccines.

Though, he did have a similar tone, in imploring a team-Canada effort to fight the virus' spread.

"There are many days to go before we get to the other side of this, but there are also many of us to get us there, so long as we each remember to do our part, and I know that we will," Trudeau said.

'MUST REMAIN EXTREMELY VIGILANT': O'TOOLE

The three main opposition parties addressed the nation following Trudeau's comments, offering up their own words of encouragement about diligently keeping up the recommended public health measures, as well as launching political attacks on the Liberals’ response.

Both Conservative Leader Erin O’Toole and Bloc Quebecois Leader Yves-Francois Blanchet delivered their remarks from self-isolation as they and their spouses have contracted COVID-19.

“The situation facing my family shows that we must remain extremely vigilant in our battle against COVID-19,” said O’Toole before pivoting to a wide-spanning speech on his policy proposals and panning the federal government for not yet approving rapid testing systems.

Blanchet spoke about where the Liberals have fallen short on supports for seniors, and said his caucus wants to see increased federal health transfers to the provinces.

“I know that you're worried,” said NDP Leader Jagmeet Singh in his response. “I know that you're worried about your kids going to school. I know you're worried about paying the bills. I know you're worried about your jobs. I know you're worried about your loved ones and our elders in long-term care homes, and you're seeing the numbers rising and you're worried about a second wave,” he continued, promising to push the government to do more to address Canadians’ resurging health and economic concerns.

In an interview with CTV News Chief Anchor and Senior Editor Lisa LaFlamme, Deputy Prime Minister and Finance Minister Chrystia Freeland defended the dual dose of federal messaging on Wednesday, saying that it’s a key time for the government to deliver the message that COVID-19 still presents a real threat to the country.

“Ultimately, the way that we will all stop COVID, the way we will flatten the curve, is by each one of us personally doing the right thing. And that means limit your social interactions… wear a mask… wash your hands, socially distance.”