Delta rise no surprise, but what’s next?
Epidemiologist Ashleigh Tuite isn’t surprised that COVID-19 infections are rising in Ontario. The situation in the province, and several others, is panning out exactly as expected.
“We’re reopening,” Tuite said. Humans are engaging with one another again — indoor dining, gyms — and the expectation was always that confirmed infections would increase, which is part of the reason why the response in Ontario has been so measured, she said.
“We didn’t just rip the Band-aid off and go straight from stage zero, to step three,” said Tuite, of the University of Toronto’s Dalla Lana School of Public Health. “We took our time.”
The bigger question for Tuite: How does this unfold in the coming weeks? “Because as much as we have a relatively highly vaccinated population, we don’t have enough vaccination to completely stop transmission, and we’re starting to interact more.”
Famed epidemiologist Larry Brilliant, who helped the globe eradicate smallpox, tweeted on Sunday that the Delta variant is one of the most infectious viruses in history. While 61 per cent of Canadians 12 and older are fully vaccinated (and 73 per cent of adults in Ontario 18 and older), “we’ve got to get to 85, 90 per cent of the population immunized before we can have the conversation about herd immunity,” said University of Ottawa epidemiologist Raywat Deonandan. “We’re nowhere near that.”
“Epidemics are all about susceptible populations, and who’s susceptible? The unvaccinated,” he said.
Ontario, British Columbia, Alberta and Quebec have all experienced a recent rise in case numbers. On Sunday, Ontario reported 423 — more infections than were reported the same time last year, and the first time since mid-june the province logged more than 400. Nationally, the seven-day moving average of 945 new cases reported daily between July 30 and Aug. 5 was a 48 per cent increase over the previous week, according to the Public Health Agency of Canada. In B.C., where the hyper-contagious Delta variant makes up 95 per cent of COVID infections, 464 new cases were reported on Friday, while a surge in cases in Central Okanagan has triggered new restrictions on bars, nightclubs and personal gatherings, indoors and out. One model is predicting B.C. could see 1,000 new confirmed infections daily by September.
While the number of people in B.C. hospitals has increased slightly, and mostly in the unvaccinated in their 40s and 50s, the numbers aren’t following the same trend line as new cases — a phenomenon the province’s public health officer Dr. Bonnie Henry has described as an apparent “decoupling” of cases and hospitalizations.
Data from Ontario and the Public Health Agency of Canada show the unvaccinated account for the majority of reported cases, hospitalizations and deaths since the country’s vaccination campaign was launched Dec. 14.
While the daily vaccination status of cases and hospitalizations in Ontario isn’t available on a provincewide basis, a recent Public Health Ontario summary of infections after vaccination found unvaccinated people are approximately eight times more likely to become a case of COVID, compared to the doubly vaccinated. Among people 60 and older, the unvaccinated are roughly 15 times more likely to be hospitalized due to COVID compared to the fully vaccinated.
Tuite said Ontario is starting to see an increase in hospitalizations and ICU admissions — “it does look like we’re starting to see a slight uptick” — and while the link between infections and hospitalizations has been weakened, she doesn’t believe it has been “decoupled” like Henry described. Unvaccinated people are still just as likely to be hospitalized, and while vaccination dramatically reduces the likelihood of severe illness, it doesn’t reduce it to zero.
Nationally, between Dec. 14 and July 17, there were 5,896 deaths due to COVID reported in the unvaccinated, compared to 89 deaths in the fully vaccinated, and 561 in the partially vaccinated.
The concern come September is that without layers of protection — masking, ideally small cohorts, improved ventilation, testing and a strong outbreak response — “you would expect a large number of children to be infected,” Tuite said.
“We’re in a highly uncertain period right now in the sense that this is entirely up to us,” she said. “I don’t think it’s inevitable that we have a bad fourth wave.”
Deonandan said a rise in hospitalizations in children’s hospitals in Florida and several other southern American states is deeply concerning.
“Previously we could have said the kids aren’t really vulnerable, they do get (COVID-19) but not really as much, and if they get it they’re asymptomatic, they’re much less likely to be hospitalized,” Deonandan said. “That does not seem to be the case any longer, at least not to the same extent.”
Children under 12 still aren’t eligible for shots. “If we were to let the virus spread unmitigated we would expect really high attack rates in kids,” Tuite said. “And what I think we are seeing in the Southern states is exactly that: you have high rates of infection and you are seeing those rare outcomes more frequently, just because there are so many infections happening.”
Deonandan said vaccine passports are “kind of needed now, to cajole a certain segment of the vaccine resistant to getting that jab.” Ontario Premier Doug Ford and Alberta Premier Jason Kenney have nixed domestic vaccine passports. Deonandan thinks political leaders are afraid of being characterized as limiting freedom. “I think this is particularly true of conservative leaders whose identity is built upon reducing government control, and not increasing it.”
But infections are driven by human behaviour as well as policy decisions, he said. “Some people have returned to life as normal, and I understand why, you feel you’ve been doubly vaccinated, why not go back to normal?”
The feeling of invulnerability that the fully vaccinated feel is, to a large extent, justified, he said. “But they’re interacting with unvaccinated people to an extent that is unhealthy, and in the context of Delta hyper-transmissibility, this is what you get.”
His advice? Vaccinate and wear masks indoors until case numbers drop, especially when you’re with people whose vaccine status is unknown.
“What I’m hoping happens is that people get a lid on this — in Ontario, cases go up to maybe 500, then vaccination uptake increases considerably and we drive it down to nothing and let public health handle the rest,” Deonandan said.