Fourth wave ‘most definitely’ here
Province could see more than 1,000 cases a day by early September, says head of science table
With Ontario seeing more than three straight weeks of growth in daily COVID-19 cases — primarily in people who have not been vaccinated — the province is “most definitely” in a fourth wave, says a top doctor with the government’s science advisory table.
And with the number of new cases currently doubling every 10 days, Dr. Peter Juni, scientific director of the science table, warns the province could see as many as 1,200 new cases per day by the time school resumes in less than a month. That’s up from a current average of just over 300.
For those who choose to remain unvaccinated, Juni has a sobering message: “If we continue on our current reopening path, the probability of unvaccinated people across all age groups to experience infection in the next six to 12 months is 80 to 90 per cent. And the risk of complications from Delta in this unvaccinated group is two to three times higher than with previous variants.”
Ontario is already seeing exponential growth in new cases, with an effective reproduction number of 1.54, meaning every 100 cases cause an average of 154 new infections.
This is similar to the fastest exponential growth rates seen during the province’s second and third waves.
To put the current trend into perspective, the only time Ontario saw week-over-week case growth faster than what we’re experiencing now was during a 10-day stretch from Sept. 14 to Sept. 23, 2020.
The provincial government ordered bars and restaurants to close by midnight and shuttered strip clubs completely two days later.
The main difference this time around, of course, is vaccines.
“We’ve never been as open as we are right now during the entire pandemic. Never. We’re only able to afford that because of the absolutely successful vaccine rollout,” Juni said. He noted, however, that “we can’t have our cake and eat it too.”
“If we want to continue to be as open as we are, we need to protect the health-care system from the unvaccinated. We can only do that if the unvaccinated are being kept out of high risk settings, such as indoor dining, gyms and nightclubs.”
And that means the possible need for future restrictions if the number of COVID hospitalizations among the unvaccinated, driven by the now dominant Delta variant, begin to overwhelm the health-care system, he said.
Because of this possibility, Juni said a better key indicator moving forward is hospital occupancy, echoing comments made Monday by Dr. Kieran Moore, the province’s chief medical officer.
As of Tuesday, 130 COVID patients were in hospital, including 109 in the ICU, according to the science table.
“If we achieve something like 400 to 500 COVID-19 hospital occupancies in the province, we will need to impose additional restrictions so that we are basically able to slow case growth down,” Juni said.
Colin Furness, an infection control epidemiologist at the University of Toronto, pegs the first day of the fourth wave in Ontario as July 16, when the province entered Step 3 of its reopening plan and also, coincidentally, the day the province’s seven-day case average hit its lowest level before starting to rise again.
“You can circle that date on a calendar, because that’s the day we said, ‘Hey, if you’re not vaccinated and you don’t care, go to the gym and exhale on everyone around you.’ That’s when we said ‘Delta, come on down!’ ” Furness said.
“The wave starts when you set up the conditions for this to happen.”
To get a sense of how low vaccination rates can strain healthcare systems, we need look no further than south of the border to the U.S., where the Delta variant has pushed cases and hospitalizations to the highest they’ve been in six months. New cases are averaging more than 126,000 cases per day, according to Johns Hopkins University. Unvaccinated residents in states in the deep south, in particular, have been hardest hit.
Ashleigh Tuite, an infectious disease epidemiologist at the Dalla Lana School of Public Health, said the pressure being put on the hospital system in the U.S. reflects the possible higher risks faced by unvaccinated individuals now because of the easing of public health measures as more people get vaccinated.
“If we were to enter into the next stage of reopening, we would be in a situation where we have relatively high numbers of cases of COVID and fewer precautions in place, so the risk that somebody who’s not vaccinated would become infected is much higher,” Tuite explained. “It’s almost like a rejigging of the calculus in terms of risk and it’s very much different for vaccinated versus unvaccinated people, which is why it’s so complicated.”
With 72 per cent of everyone over age 12 fully vaccinated, Ontario’s overall vaccine coverage is excellent by any international standard — but further progress has slowed to a relative crawl since mid-July.
The province is now administering about 50,000 vaccine doses daily, well down from a one-day peak of nearly 270,000.
That means that although Ontarians are relatively well protected compared to residents of other jurisdictions in the U.S. or Europe, the province isn’t on pace to greatly improve that protection over the coming weeks and months.
Progress is particularly slow among the youngest age cohorts; each successively younger group of Ontarians is less vaccinated than the last.
More than 90 per cent of Ontarians over 70 are fully vaccinated; that share is less than 60 per cent among 20-somethings.
About 1.5 million Ontarians under 40 are eligible to get vaccinated, but still don’t have their first shot — nearly 60 per cent of the total unvaccinated population over age 12.
Nationally, 81 per cent of all eligible Canadians over 12 have received at least one dose, while 72 per cent are fully vaccinated. Globally, Canada ranks 21st in total doses administered. “There are two ways to achieve immunity for the overwhelming majority of the population. It’s either vaccination, that’s the easy way, or infection, that’s the risky way,” Juni said.
Looking forward to the fall, Furness fears Ontario will see, in the absence of vaccinations for children, a familiar pattern in which poorer and more vulnerable neighbourhoods experience higher rates of infection in schools than richer neighbourhoods that have higher vaccine penetration and schools with decent ventilation.
“COVID is not an equal opportunity virus. It’s going to clobber you if you live in a region that’s got lower vaccine uptake, which is very closely associated with racialized, socio-economically depressed neighbourhoods,” he said. “So that is going to be a groundhog day problem.”
Juni advises against school activities like singing, the playing of wind instruments and meetings among students from different cohorts to limit spread. But even that may not be enough, he says.
“This probably will need to be re-evaluated considering that we’re now already in the fourth wave,” he said, noting that an additional challenge will be to keep children below the age of 12 protected until they have had an opportunity to get fully vaccinated, hopefully before the end of 2021.
“If case numbers are too high, this might not be possible, especially if there are unvaccinated pockets of parents and school staff.”