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Canada’s immune landscape against COVID-19 has changed completely since the advent of Omicron – with new estimates suggesting that nearly half of the population is infected.
Researchers from British Columbia analyzed thousands of blood samples on the lower continent during the pandemic to monitor antibody levels in the general population and found a huge change in the level of infection in the last few months.
BC data provided in advance to CBC News found that nearly 40 percent of the population had antibodies from a previous infection in March, up from about 10 percent in October. This number is even higher in children under 10, with nearly two-thirds already showing evidence of previous infection.
“Think about it – two out of three children,” said Dr Danuta Skowronski, a vaccine efficacy expert and head of epidemiology at the Center for Disease Control in British Columbia, who is leading the study.
“Wow, something has changed really dramatically and I think we know the name of that change … it’s Omicron.”
People were shown in downtown Vancouver last month. New data from the BC have shown a significant jump in antibody levels in the general population in the last few months, as the country struggles with the COVID-19 Omicron variant. (Ben Nelms / CBC)
Nearly 90% vaccinated, infected or both
Skovronski said nearly 60% of people aged 10 to 40 also had antibodies from a previous infection and just under 50% of those aged 40 to 60. socially engaged and vaccinated earlier.
The data also suggest that the immune system of almost 90% of the population was prepared against the virus in some way – either by vaccination, previous infection or both.
Skovronsky, whose study lay the foundations on the decision to postpone the second dose in Canada, he said that we are now in an “extremely different context” than at the beginning of the pandemic, when we were basically “completely naive” about the virus.
“It’s about almost every second of our population who has evidence of infection,” she said.
And while the data provides a useful snapshot to assess the level of infection in the community, she said it does not translate directly to the exact levels of immunity of the population.
“We cannot say that this is an indication of protection or relief from future infections, especially when new variants appear. But a prepared person is an immunologically prepared person.”
Although the data is preliminary and yet to be verified or published, it is in line with emerging data from other provinces, such as Ontario, where official estimates now show as much as 40 percent of the population is infected with COVID-19 only from December.
“We’ve had millions of infections in the last few months, most of which have not been documented,” said Dr. David Naylor, who led the federal SARS epidemic since 2003 and is now co-chair of the COVID-19 Immunity Task Force. the federal government.
“I would not be surprised if the real number is over 10 million nationally by the end of the sixth wave.
WATCH Children’s hospitals severely affected by the 6th wave of COVID-19 in Canada:
Children’s hospitals are under pressure from the 6th wave of COVID-19
The sixth pandemic wave is causing large numbers of patients and staff shortages at a number of children’s hospitals in Canada, raising concerns among parents and health experts about the spread of COVID-19 among children. 2:06
Canada has become a magnet option
Canada’s immune landscape against COVID-19 is one of the most complex in the world due to our high levels of vaccination, widespread transmission, delayed and mixed doses, and the fact that we have been a magnet for options – often with multiple circulating at once.
But does the protection we have received from vaccines, previous infection and combined hybrid immunity mean that the worst is behind us? Or could declining immunity to infection, the spread of new variants or some other pandemic curve threaten a new leap in the future?
“If there is a future option that has an infectious advantage over Omicron, we can expect it to arrive and spread here,” Naylor said. “It simply came to our notice then. The SARS-CoV-2 goes almost everywhere with a lively clip. ”
Canada bold decision yes delay and mix doses of COVID-19 vaccines have led to strong protection against hospitalization and death, but the advent of Omicron and its sub-variants has made them less protective against infection compared to previous viral strains.
New Canadian prepress studywhich has not yet been tested by partners, found that the effectiveness of just two doses of Pfizer-BioNTech, Moderna and AstraZeneca-Oxford vaccines was “excellent” against severe COVID-19 results by September 2021.
This study follows another new study, co-authored by Skovronskiand published in Clinical Infectious Diseases, which shows two doses of mRNA vaccine or AstraZeneca “gave significant and lasting protection” against hospitalization by Delta, until November 2021.
While the effectiveness of the vaccine against severe results is well maintained, the two-dose protection against Omicron infection dropped dramatically in December, falling to just 36 percent, according to one Ontario Prepress Surveyas boosters raised it to 61 percent.
This significant blow to the immunity of our population stressed the need for boosters and left us very susceptible to the fifth and sixth waves powered by Omicron, which have since torn the population apart.
“Complex” landscapes of immunity
Tulio de Oliveira, director of the Center for Epidemic Response and Innovation in South Africa, which leads the research team that identified sub-options BA.4 and BA.5, said countries like Canada now have “very complex” immune landscapes after Omicron.
“This means that what one country sees with a variant and sub-option may be slightly different from what other countries see,” he told CBC News in a telephone interview.
“But if the population’s immunity is boosted, especially through vaccination and reinforcement, it should still bode well not only for Omicron, but potentially for any new option that may emerge.”
The Canadian National Immunization Advisory Committee (NACI) strongly recommends stimulating all adults and children at high risk earlier this month and de Oliveira said the most effective way to increase the population is before a new wave of infection begins.
WATCH Canadians have called for boosters for COVID-19 to blunt the 6th wave:
Canadians call for booster vaccines against COVID-19 to blunt 6th wave
All indications are that Canada is going through the sixth pandemic wave, confirms Dr. Teresa Tam. Her message to Canadians: wear a mask and get stronger if you meet the conditions. 02:00
“That’s what countries need to focus on,” he said. “When the infection is low, it’s a great idea to include a booster campaign for people who have been fully vaccinated or have been vaccinated and infected, because then the next wave that will come will be much less deadly.
Naylor said that our previous immunity to infections, combined with the current coverage of vaccines, the continued introduction of boosters, additional doses for children and the “smart use” of fourth doses in eligible Canadians should provide “a pretty solid immune wall for summer”. .
“However, it is reasonable to remember that no one foresaw Omicron,” he said. “And so the wall of immunity can still be broken.”
“Exhaustion of territory” with current vaccines
Although the high vaccination rate and previous infections in Canada do not guarantee that the worst is behind us, it is clear that this will continue to reduce the likelihood of severe COVID-19 results for the vast majority of Canadians.
But as the virus continues to evolve into new variants that are light years away from the original strain to which the vaccines were targeted, the drive to update the formulations to target Omicron and other variants comes first.
“We need more coverage than vaccines. To my disappointment, we are still working against a strain that is long, long, long gone,” said Deepta Bhatacarya, an immunologist and professor at the University of Arizona.
“I understand that the practical reality is that these are the tools we have on hand at the moment, but we are definitely running out of space in terms of what we can expect from these vaccines, given how different Omicron is from what are vaccines against. “
Modern announced new discoveries this week, showing that a booster designed to target both the beta and the original virus strain generates a better immune response against several other variants, including Omicron.
Although this precise wording will probably never see the light of day, it portends the possibility of adapting future mRNA images to target multiple variants. But until we update the vaccines, immunity from a previous infection can work to fill the gap.
WATCH The Moderna vaccine, targeting COVID-19 variants, shows promise:
Moderna’s vaccine targeting COVID-19 variants is promising
Moderna’s new version of the COVID-19 vaccine appears to offer protection “against all concerns”, according to preliminary results released by the company. He plans to offer a vaccine that will target both the original strain and the Omicron variant this fall. 02:00
“Given the inconsistencies in the Omicron vaccine, it is almost certain that a previous Omicron infection with BA.1 would provide greater protection against the Omicron subline, such as BA.2,” Bhattacharya said.
“So people who have recovered from BA.1 are almost certainly in better shape to deal with BA.2 than someone who has just got to say a few shots of the vaccine in the past,” he said. he.
Skovronski said the Canadian population is more immunologically prepared against COVID-19 now than ever. And if…
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