Scientists are closely watching new Omicron subvariants that can evade immunity better than previous strains.
The new subvariants have the potential to drive future waves but protection against severe COVID-19 has held up in the population so far.
Updated bivalent boosters and population immunity from vaccination and prior infection will be put to the test this fall and winter.
Omicron has completely taken over the pandemic, driving massive waves of COVID-19 in Canada and around the world in the past year. Now, scientists are trying to answer a crucial question — what could it throw at us next?
COVID levels reached new heights this year as Omicron and its highly contagious subvariants fought for dominance in the population, leading to relentless spread of the virus across the country.
But as Omicron continues to mutate and produce new strains that have been shown to better evade immunity, with the potential to drive new COVID waves, scientists are warning that it may not be done with us yet.
“The challenge is, we don’t understand yet what this virus still has in store for us,” Michael Osterholm, an epidemiologist and director of the Center for Infectious Disease Research and Policy at the University of Minnesota, told CBC News.
“If you’ve got subvariants that can evade immune protection from previous infections and you’ve got waning immunity — that could set us up for a whole new set of circumstances.”
Global COVID levels have declined in recent weeks, with cases dropping 11 per cent and deaths declining by 18 per cent, according to the World Health Organization (WHO), but there are some troubling signs that rates of infection may soon pick up.
A recent spike in cases and hospitalizations in the U.K., and a recent rise of the virus in wastewater levels in Ontario and Saskatchewan have scientists bracing for potential fall and winter waves. (Ben Nelms/CBC)
“There may be a giant wave from these variants, because they’re going to spread,” said Jeremy Kamil, a virologist and associate professor of microbiology and immunology at Louisiana State University.
“But the possibility that they’re going to cause hospitals to be overwhelmed is what I wanted to dial people back on because we’re not seeing any signs of that.”
New Omicron subvariants raise concern
Omicron has outlasted all other variants because of its ability to rapidly mutate and partially escape immunity, explaining why new subvariants have consistently emerged that have completely eclipsed other strains over the past year.
The WHO said Omicron subvariants now make up 99.9 per cent of sequenced cases globally — with BA.5 at 81 per cent, BA.4 at 8.1 per cent, BA.2.75 at 2.9 per cent, while other other Omicron subvariants are responsible for an estimated 7.8 per cent of sequenced cases.
The BA.5 subvariant remains the current dominant circulating strain in Canada, making up more than 85 per cent of cases in the latest federaldata, but there are concerning new Omicron subvariants that scientists are now watching closely for signs of wider spread.
Two new subvariants,BA.2.75.2 and BQ.1.1, evolved from previous BA.2 and BA.5 strains and have mutations that have been shown to allow them to better evade immunity from vaccination and prior infection.
A new preprint lab study from Sweden, which has not been peer reviewed, found the Omicron subvariant BA.2.75.2 had “profound antibody escape” against immunity from prior infection, suggesting it may “effectively evade” immunity from antibodies in the population.
BA.2.75.2 and BQ.1.1 were also found to be “the most antibody-evasive” strains tested, “far exceeding BA.5” in a newpreprint lab study from China that has not been peer reviewed — which looked specifically at the protection from theSinovac vaccine.
Despite the fact that these two new subvariants account for just a fraction of a per cent of recently sequenced cases globally, virologists are concerned they could potentially drive future COVID waves, especially given their concerning mutations.
Tom Peacock, a virologist at Imperial College London, said they could trigger future surges because they are structurally different enough from previous wave-causing strains and can also partially escape prior immunity from vaccination and infection.
“Several of these lineages are growing fairly rapidly — this includes BA.2.75.2 and BQ.1.1,” he told CBC News. “These combined properties suggest they may have the ability to cause the next wave of COVID either regionally or globally.”
Virologists are concerned new Omicron subvariants could potentially drive future COVID waves, especially given their concerning mutations. (Ben Nelms/CBC)
If these new subvariants drive COVID levels up again in the future, the biggest unanswered question we face now is how will our immune protection from vaccination and prior infection hold up to what Omicron throws at us next?
“There’s clearly a horse race going on between these variants to replace each other,” Kamil said. “Whether that means that these variants are really going to drive a giant huge wave and spike in cases, we don’t know and it’s too early to say — but it does seem possible.”
‘Hybrid immunity’ will be tested
While vaccine effectiveness against severe outcomes has held up well, two-dose protection against Omicron infection fell dramatically compared to earlier variants — dropping to just 36 per cent in December and rising to 61 per cent with a booster, according to a new Ontario study published in JAMA.
That hit to our population immunity from vaccination against Omicron infection underscored the need for boosters earlier this year, and it left us highly susceptible to the Omicron subvariant-fuelled waves that have since ripped through the population.
“Canada had very limited population transmission of the virus for almost the first two years of the pandemic,” said Dr. Tim Evans, director of the School of Population and Global Health at McGill University and the executive director of the task force.
“Omicron changed all of that, and none of us really knew the extent to which it would change it.”
But that level of immunity in the population from vaccination and infection may have a silver lining as we head into the fall and winter — if it lasts.
Canada recently approved an updated bivalent COVID-19 vaccine that targets both the original virus and the original Omicron variant BA.1, but whether it will help prevent future waves is unclear. (Ben Nelms/CBC)
The study found two doses of a COVID-19 vaccine plus recovery from an Omicron infection provided protection equivalent to three doses, and those with protection given from both vaccination and infection may be better protected against future reinfections.
Dr. Gaston De Serres, an epidemiologist at the Quebec National Institute of Public Health and study co-author, said that while vaccination offers significant protection against infection and hospitalization — the research shows hybrid immunityprovides an edge.
“You do have some protection [with vaccination], but clearly having been infected adds a lot,” he said, noting infections can still be serious and should be avoided. “This concept of hybrid immunity being stronger and more efficient, I think, is quite well demonstrated here.”
But given that only about 40 per cent of Canadians over the age of 60 were found to have had COVID, according to thenational immunity data, that still leaves a large subset of the population more vulnerable to infection in the future — especially with newer strains.
“Omicron hasn’t affected everybody equally,” said Evans. “We still have a significant minority of Canadians who haven’t been infected and they cluster in the older age groups, which is where risk for adverse consequences from [the virus] are greatest.”
Almost two-thirds of Canadian adults have been infected with COVID-19 since the beginning of the pandemic, according to federal data. (Ben Nelms/CBC)
Bivalent vaccines may reduce risk
Canada recently approved anupdated bivalent COVID-19 vaccine that targets both the original virus and the original Omicron variant BA.1, but whether it will help prevent future waves is unclear.
“In terms of the duration of that protection and how it will apply to future variants — unfortunately we don’t have a clear answer to that,” said De Serres.
“We think that the bivalent vaccines will help reduce the risk of infections with the new viruses, but again, it’s not like it will be as effective as the vaccine was prior to the arrival of Omicron.”
The new dose doesn’t directly target dominant subvariants BA.4 and BA.5, which theU.S. approved an updated shot for this month. Pfizer and Moderna both submitted applications for Health Canada approval for their BA.4-BA.5 5 targeted vaccines earlier this month.
Ambulance paramedics unload a patient at the emergency department of St. Michael’s Hospital in Toronto on Jan. 4. Vaccinations have been effective at preventing severe illness from COVID. (Evan Mitsui/CBC)
In the meantime, public health officials across the country areprioritizing additional boosters of bivalent vaccines for vulnerable groups, including older Canadians and the immunocompromised, in hopes they will provide better immune protection for the fall.
“It remains to be seen,” Evans said, with regard to how well population immunity will hold up. “I think the trend lines are going in the right direction, and that’s clearly a function of people having good protection either through vaccination or vaccination and infection.”
How long the protection against infection and severe illness lasts, even with updated bivalent vaccines and high levels of immunity in the population is unclear, but it will likely be put to the test this fall and winter.
“We don’t know what else is going to happen. We could go another few months like this and then all of a sudden see a big change,” said Osterholm. “The immunity we do have is surely going to provide some roadblock to that — but how good it is, we don’t know.”
The Canadian government says it will donate up to 200,000 vaccine doses to fight the mpox outbreak in Congo and other African countries.
It says the donated doses of Imvamune will come from Canada’s existing supply and will not affect the country’s preparedness for mpox cases in this country.
Minister of Health Mark Holland says the donation “will help to protect those in the most affected regions of Africa and will help prevent further spread of the virus.”
Dr. Madhukar Pai, Canada research chair in epidemiology and global health, says although the donation is welcome, it is a very small portion of the estimated 10 million vaccine doses needed to control the outbreak.
Vaccine donations from wealthier countries have only recently started arriving in Africa, almost a month after the World Health Organization declared the mpox outbreak a public health emergency of international concern.
A few days after the declaration in August, Global Affairs Canada announced a contribution of $1 million for mpox surveillance, diagnostic tools, research and community awareness in Africa.
On Thursday, the Africa Centres for Disease Control and Prevention said mpox is still on the rise and that testing rates are “insufficient” across the continent.
Jason Kindrachuk, Canada research chair in emerging viruses at the University of Manitoba, said donating vaccines, in addition to supporting surveillance and diagnostic tests, is “massively important.”
But Kindrachuk, who has worked on the ground in Congo during the epidemic, also said that the international response to the mpox outbreak is “better late than never (but) better never late.”
“It would have been fantastic for us globally to not be in this position by having provided doses a much, much longer time prior than when we are,” he said, noting that the outbreak of clade I mpox in Congo started in early 2023.
Clade II mpox, endemic in regions of West Africa, came to the world’s attention even earlier — in 2022 — as that strain of virus spread to other countries, including Canada.
Two doses are recommended for mpox vaccination, so the donation may only benefit 100,000 people, Pai said.
Pai questioned whether Canada is contributing enough, as the federal government hasn’t said what percentage of its mpox vaccine stockpile it is donating.
“Small donations are simply not going to help end this crisis. We need to show greater solidarity and support,” he said in an email.
“That is the biggest lesson from the COVID-19 pandemic — our collective safety is tied with that of other nations.”
This report by The Canadian Press was first published Sept. 13, 2024.
Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.
HALIFAX – The Nova Scotia government says it could be months before it reveals how many people are on the wait-list for a family doctor.
The head of the province’s health authority told reporters Wednesday that the government won’t release updated data until the 160,000 people who were on the wait-list in June are contacted to verify whether they still need primary care.
Karen Oldfield said Nova Scotia Health is working on validating the primary care wait-list data before posting new numbers, and that work may take a matter of months. The most recent public wait-list figures are from June 1, when 160,234 people, or about 16 per cent of the population, were on it.
“It’s going to take time to make 160,000 calls,” Oldfield said. “We are not talking weeks, we are talking months.”
The interim CEO and president of Nova Scotia Health said people on the list are being asked where they live, whether they still need a family doctor, and to give an update on their health.
A spokesperson with the province’s Health Department says the government and its health authority are “working hard” to turn the wait-list registry into a useful tool, adding that the data will be shared once it is validated.
Nova Scotia’s NDP are calling on Premier Tim Houston to immediately release statistics on how many people are looking for a family doctor. On Tuesday, the NDP introduced a bill that would require the health minister to make the number public every month.
“It is unacceptable for the list to be more than three months out of date,” NDP Leader Claudia Chender said Tuesday.
Chender said releasing this data regularly is vital so Nova Scotians can track the government’s progress on its main 2021 campaign promise: fixing health care.
The number of people in need of a family doctor has more than doubled between the 2021 summer election campaign and June 2024. Since September 2021 about 300 doctors have been added to the provincial health system, the Health Department said.
“We’ll know if Tim Houston is keeping his 2021 election promise to fix health care when Nova Scotians are attached to primary care,” Chender said.
This report by The Canadian Press was first published Sept. 11, 2024.
ST. JOHN’S, N.L. – Newfoundland and Labrador‘s chief medical officer is monitoring the rise of whooping cough infections across the province as cases of the highly contagious disease continue to grow across Canada.
Dr. Janice Fitzgerald says that so far this year, the province has recorded 230 confirmed cases of the vaccine-preventable respiratory tract infection, also known as pertussis.
Late last month, Quebec reported more than 11,000 cases during the same time period, while Ontario counted 470 cases, well above the five-year average of 98. In Quebec, the majority of patients are between the ages of 10 and 14.
Meanwhile, New Brunswick has declared a whooping cough outbreak across the province. A total of 141 cases were reported by last month, exceeding the five-year average of 34.
The disease can lead to severe complications among vulnerable populations including infants, who are at the highest risk of suffering from complications like pneumonia and seizures. Symptoms may start with a runny nose, mild fever and cough, then progress to severe coughing accompanied by a distinctive “whooping” sound during inhalation.
“The public, especially pregnant people and those in close contact with infants, are encouraged to be aware of symptoms related to pertussis and to ensure vaccinations are up to date,” Newfoundland and Labrador’s Health Department said in a statement.
Whooping cough can be treated with antibiotics, but vaccination is the most effective way to control the spread of the disease. As a result, the province has expanded immunization efforts this school year. While booster doses are already offered in Grade 9, the vaccine is now being offered to Grade 8 students as well.
Public health officials say whooping cough is a cyclical disease that increases every two to five or six years.
Meanwhile, New Brunswick’s acting chief medical officer of health expects the current case count to get worse before tapering off.
A rise in whooping cough cases has also been reported in the United States and elsewhere. The Pan American Health Organization issued an alert in July encouraging countries to ramp up their surveillance and vaccination coverage.
This report by The Canadian Press was first published Sept. 10, 2024.
