When will the pandemic be over in Ontario? Here’s what scientists say
More than 80 per cent of eligible Ontarians have now been fully vaccinated against COVID-19 and, with the possibility that vaccines will be offered to young children in the coming months, the pandemic's familiar wave-after-wave pattern of new infections could soon calm.
Scientists believe that as more people increase their immunity to the virus either through vaccination or infection, cases in Ontario are on track to drop to endemic levels as early as spring, provided of course that a more transmissible and vaccine-evasive variant doesn't rear its head in the meantime.
The implication of COVID-19 becoming endemic - that is, infections of the virus occurring at some consistent baseline level in the population - is that we will simply have to learn to live with it.
Unless we can vaccinate beyond the level of herd immunity, then we're always going to have cases around," said David Earn, professor of mathematics and faculty of science research chair in mathematical epidemiology at McMaster University. Herd immunity is this wonderful goal which seemed plausible early in the pandemic but with The Delta variant being so contagious and the vaccines not being absolutely perfect at preventing transmission, I think it's an unattainable goal at the moment."
Living with an endemic prevalence of COVID need not be a life sentence for our work and social lives, nor our economy; to date, vaccination against the virus has proved incredibly effective at preventing severe illness, hospitalization and death. Experts harbour a beacon of hope that COVID will become much like other endemic diseases we have grown accustomed to, such as influenza and the rhinovirus, which causes the common cold, that neither result in widespread negative health outcomes nor serious public health restrictions.
In other words, we accept some risk but we don't let it ruin our lives.
That's kind of the goal with the vaccines - to make it so that we turn a very serious illness into a mild illness," said Dr. Jeff Kwong, professor of public health and family medicine at the University of Toronto. You get COVID and it's like a cold ... you'll be sick for a few days, you'll recover and then you can carry on with your life."
While the hope is that we could reach some level of COVID-19 endemicity in Canada sometime early next year following the vaccination of children between the ages of five and 11, such an aspiration could be tempered by the emergence of a variant even more potent and transmissible than the formidable Delta, a scenario experts say is not out of the realm of possibility.
Already a new variant, dubbed Mu, has spread to about 50 countries, including Canada, since it was first detected in Colombia in January. Mu, which was added to the World Health Organization's list of variants of interest in August, is thought to be better at evading immunity than Delta but does not seem to be as transmissible. Still, Dr. Maria Van Kerkhove, an infectious disease epidemiologist and the WHO's COVID-19 technical lead, maintains that Delta, which is on the WHO's more serious list of variants of concern, remains dominant worldwide.
In countries that have both Mu and Delta, Delta outcompeted Mu," Verkove said this week during a WHO media briefing, noting that Delta has now spread to over 185 countries.
It is more transmissible and it is outcompeting" other variants, she added.
While endemicity seems like the least worst option given that there will remain pockets of unvaccinated people across all age groups, getting there could take longer if, through its continued transmission, Delta mutates into something stronger.
The more a virus reproduces, the more opportunities there are for random mutations to be introduced. Most mutations amount to nothing, but occasionally a virus will evolve a gain-of-function" mutation which can make it more transmissible and resilient. In the worst case, Delta mutates to the point where it can get around our immune systems and the vaccine.
Unfortunately SARS-CoV-2 is a virus that is demonstrating that it can have evolution that is relevant in this way," noted Earn. We have to get to the point where most of the world is vaccinated in order to reduce the number of opportunities for new evolution."
On that score, Ontario has done well, relatively speaking. More than 86 per cent of adults in the province have now received at least one dose, while nearly 81 per cent have been fully vaccinated. And with Pfizer-BioNTech announcing this week that it was planning to submit encouraging data on a trial of its vaccine in children aged five to 11 to the U.S. Food and Drug Administration sometime next month, approval in this country could come before the end of the year.
Just this week, British Columbia's health officer Dr. Bonnie Henry said her province was actively preparing" to inoculate children between the ages of six and 11 with the Pfizer vaccine if Health Canada approves it.
Dr. Andrew Morris, infectious diseases specialist at Mount Sinai Hospital in Toronto, said while most parents will be keen to get their kids vaccinated, some won't be.
It's important we don't alienate those honestly worried about the lack of data, especially because we know the sample size of the study, roughly 1,500 getting vaccinated, is insufficient to assure us of safety," he said. That being said, for COVID, vaccine is always better than infection."
Getting jabs into the arms of young children won't stop the pandemic, stressed Dr. Peter Juni, scientific director of Ontario's COVID-19 Science Advisory Table, but could change its face insofar as we can be less concerned with the risk of transmission in schools. This would translate into reduced odds of being forced to close classrooms or schools due to outbreaks, as well as making it less likely that Ontario's limited number of pediatric ICU beds become overwhelmed with infected children.
The threats to five-to-11 year olds in this pandemic have never been as high as now. For children, unlike all the other age groups, there is no vaccine protection that compensates partially for the increased risk associated with Delta ... there is increased pressure because of higher contact rates in society in general and between kids," Juni said. The point is, once we've vaccinated kids, we will have one less parameter that we need to consider when controlling the pandemic."
For its part, Pfizer Canada says it plans to file its trial data to Health Canada to support a potential authorization but could not provide specific timelines.
We share the urgency to provide the data that could help support the decision by regulatory authorities to make the vaccine available to school-aged children as early as possible," said Pfizer Canada spokesperson Christina Antoniou.
Why won't vaccinating children end the pandemic? There are just too many people in other age groups who continue to remain unvaccinated, Juni explained. Endemicity will come instead through more painful means.
There is this bumpy transition to endemicity that includes the majority of those people who are unvaccinated getting infected and therefore developing immunity," he said. The last frontier is actually reached once probably more than 95 per cent of the entire population has reached immunity one way or another."
Kenyon Wallace is a Toronto-based investigative reporter for the Star. Follow him on Twitter: @KenyonWallace or reach him via email: kwallace@thestar.ca