The first wave of COVID-19 is subsiding in Canada, with daily case numbers and hospitalizations falling to rates not seen since the beginning of the pandemic.
Predictions on when a second wave of COVID-19 could hit have ranged from the fall and winter months of this year, when flu season traditionally starts, to early next year, similar to the way the pandemic began.
But experts say the likelihood of a second wave isn't set in stone, and Canada could instead see several smaller waves in the coming months or avoid a second wave altogether — especially if we keep our guard up.
"There's actually nothing preordained about a second wave," said Steven Hoffman, director of the Global Strategy Lab and a global health law professor at York University in Toronto who studies pandemics.
"We might have a second wave, we might have a third, fourth and fifth wave — we might not have a second wave at all."
Dr. Isaac Bogoch, an infectious disease physician and scientist with Toronto General Hospital, said instead of one cohesive second wave, we'll likely face smaller outbreaks in the coming months that will need to be clamped down on quickly.
"It's going to be a game of whack-a-mole," he said.
"We're basically going to be trying to rapidly identify small outbreaks as soon as possible, quelling those small outbreaks and preventing them from snowballing into larger outbreaks and a larger epidemic."
Israel saw hundreds of new infections after reopening schools, South Korea faced a spike in cases at a nightclub district in Seoul while an outbreak at a meatpacking plant in Germany led to renewed lockdown measures.
Meanwhile, countries like Singapore, Hong Kong and Taiwan quickly flattened the curve of their first wave and have so far avoided a second wave of infections altogether while keeping strict physical-distancing measures in place.
China moved quickly to quell a new coronavirus outbreak in Beijing this month, raising its emergency level, suspending reopenings and cancelling more than 60 per cent of flights in and out of the capital after reporting at least 256 new cases since early June.
Bogoch said if Canada takes a similar approach to controlling new outbreaks, we can avoid more drastic measures like shutting down nonessential businesses and reimposing lockdown measures across the country for the long term.
"If we jump on it quickly and we have the capacity to do the early identifications, contact tracing and isolation, we can get through this without a big second wave," he said.
"But if we don't, if we let our guard down, well, here it comes."
Canadians vulnerable to COVID-19
The largest risk factor for another wave of infection is connected to the fact that most Canadians are susceptible to COVID-19 simply because they haven't had it.
Canada's Chief Public Health Officer Dr. Theresa Tam said almost 2.5 million Canadians have been tested for COVID-19, with an average of about four per cent testing positive and more than 100,000 confirmed cases.
"We have very small penetration of this disease in our society," said Raywat Deonandan, a global health epidemiologist and an associate professor at the University of Ottawa.
"That means the vast majority are still susceptible, and if they are susceptible, then it doesn't take a whole lot for something to trigger another explosive growth."
For that reason, Deonandan said there is a mathematical probability that another wave of infection is possible, but it may be less severe based on what we've learned about how to control the virus in the past six months.
"We know that it loves mass indoor gatherings. That seems to be where the super spreading events tend to be: churches, karaoke bars, parties, nightclubs," he said.
"So given that, that's kind of our way of controlling the second wave — if we just really monitor large indoor activities or prevent them entirely."
York University's Hoffman said while physical distancing and lockdown measures have drastically lowered the number of new cases and hospitalizations in Canada, they continue to rise globally — putting us at further risk.
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"It's just very likely that so long as this virus is circulating around the world, it will at some point come back to Canada," Hoffman said. "Even if we eliminated it from our country."
Knowledge of the virus may help fend off future waves
Our understanding of the novel coronavirus and how COVID-19 presents in the human body has increased dramatically in the past six months, and we now know more about how to react to outbreaks quickly and treat the disease itself more effectively.
"We've learned that this is a very strange disease that seems to manifest differently in different populations, different age groups and that the symptomatology is not at all what we might have expected at first," Deonandan said.
"This idea of losing your sense of smell, for example, that took everyone by surprise. We also learned about asymptomatic and presymptomatic transmission."
He said it was wrongly assumed early in the pandemic by experts around the world that simply testing symptomatic patients early could control the spread of COVID-19, much like with an influenza outbreak.
The World Health Organization also recently backtracked on a claim that the spread of COVID-19 from people who do not show symptoms is "very rare," later conceding that asymptomatic individuals can transmit the virus.
There were also early concerns about the threat of different modes of transmission, either through surfaces or feces, and Deonandan said that caused confusion about how to prevent infection at a critical time.
"It seems now that almost all of it is being driven by droplets and aerosol, mostly droplets," he said.
"So we can direct our efforts toward controlling droplet transmission, and that would help us mitigate a second wave."
That's why physical distancing, proper hand hygiene and wearing masks when appropriate are essential tools in fighting the spread of COVID-19.
Jason Kindrachuk, an assistant professor of viral pathogenesis at the University of Manitoba in Winnipeg and Canada Research Chair of emerging viruses, said we can use our increased understanding of transmission to fend off future waves.
"We're better prepared than we were the first round because we have a better idea of what this virus is and a little bit more about how it behaves," he said.
"We've learned probably around five to 10 years worth of research in the last six months."
Yet while we know more now about the virus in order to prevent infection, Kindrachuk said the first wave has exposed our vulnerabilities, especially in long-term care homes, where more than 6,000 Canadians have died from COVID-19.
"If the virus hits a resurgence in Canada again," he said, "as long as we can try and limit the spread within those vulnerable communities, we know that the majority of the rest of the population is manageable."
Hoffman said he hopes we've learned enough about protecting long-term care home residents and ensuring employees are supported to take necessary precautions in order to prevent more outbreaks in the months ahead.
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"That's what has allowed this outbreak to continue for longer, affecting more vulnerable people, and as a result has meant that we are only able to start lifting these layers of protection at a later point after other countries have already been able to do so," he said.
"It's just a total disaster and so preventable."