When it comes to another major outbreak of COVID-19 in Toronto, it's not a matter of "if" it will happen, but "when" and "how," experts say.

This was the main message put forth by Toronto Medical Officer of Health Dr. Eileen de Villa during a press conference announcing the city's new COVID-19 Resurgence Plan Monday afternoon.

Speaking alongside Mayor John Tory, city manager Chris Murray, and health board chair Joe Cressy, de Villa spoke to the almost-certain possibility of a "second wave" hitting Toronto in the coming weeks or months.

"The first stage of this outbreak is behind us," said de Villa, but "there is no question that we will see a resurgence."

Dr. Eileen de Villa is the city's medical officer of health.

Toronto’s chief medical officer of health has warned that a resurgence of COVID-19 is inevitable and that a second lockdown remains a possibility. pic.twitter.com/x5YMPmVnJF

— Spacereporternews (@Spacereportern1) August 31, 2020

Toronto's top doctor spoke of three potential scenarios for the forthcoming second wave, based on projections from the University of Minnesota's Centre for Infectious Disease Research and Policy.

Scenario 1 would see a series of small, successive waves hit the city throughout the course of 2021. Scenario 2 would involve "a large wave in the fall or winter, with successive smaller waves in 2021."

The third scenario, described as a "slow burn," would simply see ongoing tranmission of the virus with no significant patterns.

Being that there is no way to tell what will happen, the city has devised a comprehensive and flexible plan which "outlines priorities and associated actions that the City will implement in the event of a resurgence of COVID-19."

Additionally, the plan takes into account the colder weather of the coming months and the associated impacts on people and services.

— City of Toronto (@cityoftoronto) August 31, 2020

These priorities, which you can read about in full right here, include the implementation of public health measures, supporting vulnerable populations, supporting City employees, mitigating the impact to Toronto's economy and ensuring the resiliency of municipal services.

Among the potential measures listed by the City are a return to emergency child-care services for front-line workers, enhanced bylaw enforcement and establishing a voluntary self-isolation site for people with COVID-19 who cannot safely quarantine at home.

"While scientists are working with speed and determination, we still don't expect highly effective treatments in the very near future, and we aren't planning on vaccine availability before the spring of 2021 at the earliest," said de Villa.

"Until then, we have to find a way to live with COVID-19 in our city."

The City's fight against #COVID19 has never stopped and we know it will never stop until we have a vaccine. But we have learned from this fight and we have worked to make sure we can reopen with confidence, based on public health advice and with proper safety measures in place. pic.twitter.com/YVvfxIcRwl

— John Tory (@JohnTory) August 31, 2020

Toronto Public Health says the best ways to keep everyone as safe as possible are wearing a mask, washing your hands, watching your distance from others and adhering to the provincial government's social gathering restrictions.

"Our success in living with the virus depends greatly on the choices we all make to minimize risk to ourselves and others in the coming months," said de Villa. "Making the right choices as individuals will strengthen the work by Toronto Public Health and our partners to limit the impact of COVID-19 on our city."

"These plans are based on the same clear and fearless public health advice we have had throughout this pandemic, advice which we have always accepted and acted on," said Tory of the city's planned response to a second wave.

"We've said many times that COVID-19 is a marathon not a sprint. The public should know that we have the plans in place for the next phase of this long marathon."