Health·Second Opinion

Why Canadians need to keep their guard up in the 4th wave — even if they're fully vaccinated

The delta variant has changed the rules of the game — raising the immunity threshold we need to hit, increasing risk in our day-to-day lives and requiring even fully vaccinated Canadians to keep their guard up. 

Delta variant changing rules of the game, but unvaccinated prolonging pandemic

Waning immunity sparks debate about need for COVID-19 booster shots

3 months ago
2:03
Recent studies show a drop in effectiveness for COVID-19 vaccines, but the lack of information about how severe breakthrough cases were has sparked a debate about whether booster shots are necessary. 2:03

This is an excerpt from Second Opinion, a weekly roundup of health and medical science news emailed to subscribers every Saturday morning. If you haven't subscribed yet, you can do that by clicking here.


Canadians are entering one of the most confusing chapters of the pandemic — and many may be left wondering why we're not where we'd hoped to be after becoming one of the most vaccinated countries in the world.

Reports of waning immunity from COVID-19 vaccines, the potential need for booster shots and the possibility of breakthrough infections among the fully vaccinated may be leading many of us to second guess what we can and can't do safely in the fourth wave.

And the more contagious, potentially more deadly delta variant has prolonged the pandemic, made daily life more difficult to navigate and turned back the clock on our collective plans to return to a relatively normal life.

"Everyone needs this damned virus to go away," said Dr. David Naylor, who led the federal inquiry into Canada's national response to the 2003 SARS epidemic and now co-chairs the federal government's COVID-19 immunity task force. "But it's not done with us yet."

It was easy to think that once most of us rolled up our sleeves and did our part to get vaccinated and protect ourselves and our communities from COVID-19 that this would all be over, but the unfortunate truth is that we still have a ways to go.

"We need to rethink this," said Linsey Marr, an expert on virus transmission at Virginia Tech in Blacksburg, Va. "It is emotionally upsetting because we thought we saw the light at the end of the tunnel — but apparently the tunnel is longer." 

Despite efforts to stave off another wave of the pandemic through widespread vaccination, Canada is continuing to see a troubling rise in COVID-19 levels across much of the country. (Evan Mitsui/CBC)

Unvaccinated driving Canada's 4th wave

The hard truth is that despite our collective efforts to stave off another wave of the pandemic through widespread vaccination, Canada is continuing to see a troubling rise in COVID-19 levels across much of the country.

Over the past week, new COVID-19 cases have risen to an average of 2,848 per day — an increase of 29 per cent over the previous seven days. 

Daily hospitalizations have also climbed 39 per cent week-over-week to an average of 917 across the country, while ICU admissions are also up by an average of 29 per cent per day to 340 over the past week. 

That's despite having 66 per cent of the Canadian population fully vaccinated — a number that has plateaued in recent weeks, but is remarkably high nonetheless. 

So why isn't that enough? The answer lies with those who haven't yet gotten a shot.

Since vaccines became available in December, just 0.8 per cent of cases, one per cent of hospitalizations and 1.4 per cent of deaths from COVID-19 have been in fully vaccinated Canadians, according to the latest available data from the Public Health Agency of Canada.

"When we look at where cases and certainly hospitalizations are showing up right now, we're seeing massive over-representation in unvaccinated communities," said Jason Kindrachuk, an assistant professor of viral pathogenesis at the University of Manitoba and Canada Research Chair of emerging viruses. "So the vaccines are working." 

But there are still millions of Canadians who have yet to get vaccinated — either by choice or due to a lack of access or eligibility —  and that's putting all of us at risk.

Unvaccinated Canadians pose risks to vaccinated

The bottom line is the vaccines aren't perfect (and were never purported to be) and even the fully vaccinated are at some risk of COVID-19, which adds to the confusion of how Canadians should proceed in the weeks and months ahead. 

Dr. Allison McGeer, a medical microbiologist and infectious disease specialist at Toronto's Mount Sinai Hospital who worked on the front lines of the SARS epidemic in 2003, says the unvaccinated pose two different threats to vaccinated Canadians in the fourth wave.

"Firstly, they pose a direct risk of transmission, and while the vaccine is very effective at protecting you from serious illness and death — it's not 100 per cent. Nothing in life is 100 per cent," she said.

"The second thing that unvaccinated people do is they increase the spread of coronavirus in the population. So if you release restrictions, unvaccinated people contribute substantially more to the growth of transmission in the community." 

To put it bluntly, the longer the remaining Canadians put off getting a shot — and until we can get kids under 12 vaccinated — the more the pandemic drags on.

And while we've come a long way since the beginning of the pandemic, we're still nowhere near where we need to be to control the delta variant. 

Naylor says that even though Canada has vaccinated over 83 per cent of our eligible population over the age of 12 with one dose and more than 75 per cent with two, that's still not enough to stave off a fourth wave. 

"That's very helpful and should mitigate the toll of the fourth wave compared to earlier waves," he said. "But it makes no sense to leave a lot of immunological room for this virus to spread and cause more harm." 

Delta has changed the rules of the game — raising the immunity threshold we need to hit, increasing risk in our day-to-day lives and meaning even fully vaccinated Canadians need to keep their guard up. (Graham Hughes/The Canadian Press)

Public Health Ontario, a provincial government agency, said in a recent report that the delta variant has kicked the possibility of herd immunity further down the road — meaning we may now need an estimated 90 per cent of the population fully vaccinated to get there. 

"Vaccines are not a panacea, but if everybody got vaccinated — this is done," said Raywat Deonandan, a global health epidemiologist and associate professor at the University of Ottawa.  "Despite the fact these vaccines aren't perfect." 

Delta changing rules of the game

The problem we face at this stage of the pandemic is that delta has changed the rules of the game — raising the immunity threshold we need to hit, increasing risk in our day-to-day lives and meaning even fully vaccinated Canadians need to keep their guard up. 

But instead of coming together in a cohesive way, the country is once again divided over vaccine passports, mask mandates and reinstating public health restrictions — leaving a patchwork system across the country that leaves room for the virus to spread. 

Ontario and Alberta have vehemently rejected the idea of vaccine passports to date, although Ontario may soon change course, while British Columbia joined Quebec and Manitoba in announcing passports for the fully vaccinated in response to the fourth wave. 

Saskatchewan announced this week that not only would it not be implementing vaccine passports — it also won't reintroduce indoor mask mandates or lower capacity limits on gatherings despite rising COVID-19 levels.

That's despite the fact that both B.C. and Quebec saw massive upticks in vaccinations after introducing vaccine passports and Manitoba brought back mandatory masks indoors. 

"I'm really disappointed that some provinces have not moved forward with vaccine certificate programs. This isn't about civil liberties. It's like smoking in a crowded restaurant," said Naylor. 

"Vaccine certificates are also a spur to those who are unvaccinated or partially vaccinated to get on with protecting themselves and others. One can only hope all the premiers eventually wake up to the harm they are doing by side-stepping this sensible measure." 

WATCH | B.C. announces vaccine passport amid COVID-19 spike

B.C. announces vaccine passport amid COVID-19 spike

3 months ago
2:43
B.C. has followed Quebec's lead and will implement a vaccine passport system to access non-essential services. 2:43

The reality is that until that happens, Canadians may need to take matters into their own hands by using the proven tools we have at hand to blunt the worst of a delta-driven fourth wave.

"We have to appreciate that there's a balance," Kindrachuk said. "Vaccines are certainly an important way out of the pandemic for us, but they're not the only way." 

Those tools include wearing high quality masks when needed, filtering the air indoors and avoiding crowded indoor spaces with poor ventilation — especially with the unvaccinated.  

Canadians may need to take matters into their own hands by using the proven tools we have at hand to blunt the worst of a delta-driven fourth wave. (Peter Power/The Canadian Press)

"Delta is obviously much more transmissible and the vaccine helps protect against that, but it's not 100 per cent. So it almost puts us back where we were a year ago with a less transmissible virus and no vaccines," Marr said.

"At the same time, it's not as upsetting as the first time around because we know what we need to do."

ABOUT THE AUTHOR

Adam Miller

Senior Writer

Adam Miller is a senior health writer with CBC News. He's covered health, politics and breaking news extensively in Canada for over a decade, in addition to several years reporting on news and current affairs throughout Asia.

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