This is an excerpt from Second Opinion, a weekly report on health and medical sciences emailed to us Subscribers every Saturday morning. If you have not yet subscribed, you can do so by clicking Here.
Canada will likely face a fourth wave of the pandemic as the highly contagious delta variant continues to spread before borders and schools reopen, but there is growing optimism that another surge will not bring the country back to crisis point.
Canadian immunologists, virologists and infectious disease specialists say we can do better than in previous waves, with a lower rate of serious infections, due to the effectiveness of COVID-19 vaccines and Canadians’ willingness to be vaccinated.
But our start-up is on its way to plateauing and there are still large sections of the population that are not immune – either by choice or by lack of access or eligibility – including the millions of Canadian children who are back in school in just over a month.
“We’re going to see a spike in cases again,” said Matthew Miller, associate professor of infectious diseases and immunology at McMaster University in Hamilton.
“Maybe it’s like last year, as we approach fall and the cold weather arrives. But hopefully those bumps are just little hills, not mountains like previous waves.”
How bad is the fourth wave for Canada?
The severity of the fourth wave in Canada will be determined in large part by levels of COVID-19 immunity in the population from previous vaccinations or infections, which can prevent community transmission and stop severe cases from overwhelming hospitalizations.
Canada had more than 1.4 million cases of COVID-19 So far, but only 2.6 percent of Canadians She was found to have antibodies due to a previous infection with the coronavirus in early 2021.
“The question is – is there enough immunity in the population? No,” said Rewat Dionandan, a global health epidemiologist and assistant professor at the University of Ottawa.
The reason for this is that we measure the immunity of the population with recovered cases and vaccinations.
More than 80 percent of eligible Canadians age 12 and older have received at least one shot, and more than 60 percent have received one. But that number drops to about 70 percent with a single dose and just over 50 percent from full vaccinations when you consider the entire country’s population.
Although Canada does not yet have sufficient immunity, Deonandan says we can “artificially create” adequate protection by using interventions such as hiding indoors to help “build walls” around unvaccinated Canadians as COVID-19 becomes seasonal.
“We are witnessing the arrival of the endemic phase of this disease in places around the world,” he said. “Because often they don’t have enough vaccinated people – it’s because of that.”
Delta threatens to push back the wave of COVID-19 outbreak
Another major factor in Canada’s ability to fend off a severe fourth wave is the spread of more contagious, possibly deadlier Delta variable, which is driving COVID-19 levels back in countries around the world.
“We know by watching the UK, for example, that Delta is very, very capable of ripping apart unvaccinated people very quickly,” said Dr Dominic Mertz, an infectious disease physician and associate professor of medicine at McMaster University.
“Any percentage of the unvaccinated people in the population is at a very high risk.”
The UK has seen a spike in COVID-19 levels in recent weeks, To put pressure on the health care system. Israel has Re-mask the States response to new disease outbreaks. The United States saw a Increase in unvaccinated countries Driven by Delta.
New study in the New England Journal of Medicine (NEJM) This week it found that two doses of the Pfizer-BioNTech vaccine were 88% effective against the delta variant, while two doses of the AstraZeneca-Oxford vaccine were 67% effective.
But there are conflicting reports from the real world about the effectiveness of the vaccine against Delta, including New data from the Israeli Ministry of Health This suggests that the Pfizer injection is only 39 percent effective against infections — but much better at preventing severe disease.
Watch | Why is the delta variable different from the others:
The respiratory specialist details what is known about the delta variant of the coronavirus, including what makes it different, how dangerous it is, and whether vaccines protect against it. 4:26
Dr. Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, told CBC power politics Friday said the US still had a “significant percentage” of the unvaccinated population at greater risk than Delta.
“That’s something that we absolutely need to get right, because when you’re dealing with a variable like a delta variable that’s very efficient at spreading from person to person, you’re going to see sort of an increase in cases,” he said.
“And for those who are vulnerable, such as the elderly and people with underlying conditions, the chances of them being hospitalized increase.”
When borders reopen, unprotected schools are left at risk
Canada could also be at increased risk of delta exposure due to Border reopening For US travelers next month and international travelers in September, along with the return of school, which could put unvaccinated Canadians at greater risk of exposure to COVID-19.
“You definitely will,” said Dr. Allison McGeer, a medical microbiologist and infectious disease specialist at Mount Sinai Hospital in Toronto. “In addition, the greater travel that we do within the country will increase the risk of variants.”
“We shouldn’t be surprised if the delta variable starts to increase dramatically and we shouldn’t be surprised if we have to go back to a certain level of travel and other restrictions.”
The largest group of unvaccinated Canadians are children under the age of 12, who are not yet eligible for COVID-19 vaccines despite ongoing clinical trials. Experts say reopening schools in September could put them at greater risk.
“It is important that we start reporting the percentage of vaccinations, including children, because that is our actual number,” said Alison Kelvin, assistant professor at Dalhousie University and a virologist at the Canadian Center for Vaccine Science and the Vaccines and Infectious Diseases Organization.
“Given that we want herd immunity to be above 85 percent, we’re not going to get there without kids.”
Until children under age 12 are eligible for vaccination in Canada, Kelvin says those with less effective immune responses to COVID-19 vaccines — including older and immunocompromised Canadians — will remain at risk.
“Children can’t be vaccinated, and different species like Delta are more transmissible – and there seem to be case reports of increased severity of illness in children when they become infected,” she said. “This is something we need to monitor going forward.”
Future variables pose an unknown threat
One unknown threat that Canada faces is the potential for more transmissible variants to emerge in the coming weeks and months that could be worse than Delta, as COVID-19 continues to devastate unvaccinated countries around the world.
Canada was hit hard by the alpha variant at a time when our vaccination campaign was not yet gaining traction, and new and more dangerous variants appeared more frequently in countries still severely affected with each passing wave.
“We’ll definitely see other variables,” Kelvin said. “If it’s going to be more severe or a different kind of anxiety, that’s another question.” “But it’s interesting that … there seems to be an increase in transmissibility with each passing time and we see new variables.”
This isn’t something typically seen with other circulating viruses like influenza, Kelvin said, meaning that the unpredictability of this virus leaves its future an open question.
It’s likely that COVID-19 will become endemic in Canada and around the world, and return every year like the flu, Miller says, and our ability to control it depends on our ability to vaccinate more people.
“It’s supposed to keep evolving for decades,” he said. “It’s not going to happen anywhere. But we have amazingly successful vaccines.” “The truth is that there is light at the end of the tunnel. This will end with all things finished.
“But if you haven’t been vaccinated, you will almost certainly – at some point – get infected.”
This is an excerpt from Second Opinion, a weekly report on health and medical sciences emailed to us Subscribers every Saturday morning. If you have not yet subscribed, you can do so by clicking Here.
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