Getting infected more than once by subvariants in the Omicron family does seem possible, but appears rare, scientists in Denmark found in a recent real-world study — offering reassurance that countries won’t experience another sudden surge of infections.
The early research, which was published online as a preprint on Tuesday and has not yet been peer-reviewed, involved an analysis of recent SARS-CoV-2 infections by a team from the Statens Serum Institut (SSI), a top Danish public health institute.
Many of those were the highly-contagious BA.2 subvariant, which is now dominant in that country — and on the rise elsewhere — after squeezing out other Omicron subvariants featuring different mutations, including the original lineage, as well as BA.1, BA.1.1 and BA.3.
Out of nearly two million infections logged in Denmark between mid-November and mid-February, the researchers zeroed in on those who tested positive twice between 20 and 60 days apart, and whose infections had gone through previous genomic surveillance and were labelled as a specific subvariant.
Fewer than 1,800 people hit those criteria, and a subset of close to 1,000 samples were randomly selected for sequencing.
The team ended up finding 187 cases of reinfection, including 47 instances where BA.2 reinfections happened shortly after a BA.1 infection, “mostly in young unvaccinated individuals with mild disease not resulting in hospitalization or death,” the team wrote.
One of the researchers, Dr. Troels Lillebæk, chair of Denmark’s SARS-CoV-2 Variant Assessment Committee, told CBC News this offers the first evidence of reinfections among members of the Omicron family, but it appears this is a “quite rare phenomenon.”
“If it was a major problem that you could catch BA.2 after BA.1, you could imagine a new wave,” he said.
“This does not really point in that direction.”
BA.2 cases rising in Canada
After weeks of uncertainty, it’s a welcome finding, following the upward spike in BA.2 cases in multiple countries that sent scientists scrambling to understand whether the heavily-mutated subvariant could prolong this year’s Omicron wave — or even spark a new one.
In Denmark, BA.2 infections now make up roughly nine in 10 cases, with cases also rising in countries including Norway, South Africa and the U.K.
Here in Canada, the subvariant was barely a blip in federal data by early January, but the latest-available data by month’s end suggest it makes up roughly one in 10 cases, with recent data still accumulating.
Its rise comes as the overall Omicron wave is subsiding, and while much of the country is further loosening or outright dropping COVID-related restrictions, granting Canadians the opportunity to socialize indoors more freely than at many points during this more than two-year pandemic.
Employees are vaccinated at a COVID-19 vaccination clinic at Montreal’s CAE headquarters in April 2021. It’s unlikely Canada will experience another wave of infections tied to the BA.2 subvariant, experts say, in part thanks to the country’s high vaccination rate. (Paul Chiasson/The Canadian Press)
The virus will still be circulating, said Dr. Zain Chagla, an infectious diseases specialist and professor at McMaster University in Hamilton, Ont., but based on the emerging evidence about how BA.2 operates, it’s unlikely Canada will experience another wave of infections tied to this subvariant.
That’s in part thanks to Canada’s high vaccination rate, he said, coupled with the spike in exposure brought on by the original Omicron surge which infected huge numbers of Canadians in recent months, providing millions with hybrid immunity to this evolving virus.
“So many people are vaccinated and boosted or have had BA.1 recently that they’re not very likely to be reinfected so quickly afterwards with BA.2,” echoed Angela Rasmussen, a virologist with the University of Saskatchewan’s Vaccine and Infectious Disease Organization (VIDO).
Questions over disease severity
While its capacity to transmit and reinfect is becoming more clear, there are still questions over what level of serious disease BA.2 is capable of causing.
Real-world data on clinical severity from South Africa, the U.K., and Denmark, where immunity from vaccination or natural infection is high, shows no reported difference in severity between BA.2 and BA.1, the World Health Organization noted on Tuesday.
“Now, that could change as BA.2 pushes out BA.1 and makes its way into higher risk [unvaccinated] people,” noted Jason Kindrachuk, an assistant professor in medical microbiology and infectious diseases at the University of Manitoba, in an email exchange with CBC News.
WATCH | Pfizer testing Omicron-based vaccine amid concerns about subvariant:
Pfizer testing Omicron-based vaccine amid concerns about twin variant
29 days ago
Duration 2:02
Pfizer has started testing an Omicron-based COVID-19 vaccine to see if it can prevent infection and not only severe illness. The testing comes as researchers investigate an emerging variant described as Omicron’s twin. 2:02
Early preliminary laboratory results from a team in Japan using hamster models — which allowed the researchers to infect subjects that didn’t have any prior immunity — did suggest BA.2 may cause more severe disease than BA.1 in those without previous vaccination or viral infection.
The findings, recently published online as a preprint, suggest the fast-spreading subvariant may be closer to earlier variants in terms of disease severity.
But Rasmussen, from VIDO in Saskatchewan, stressed that animal studies don’t paint a full picture of how pathogens like SARS-CoV-2 will impact humans.
And while scientists should continue studying BA.2, she said the bigger focus should be on increasing vaccination rates and booster shot uptake to give people their best chance at fending off potential infections — whether that’s an Omicron reinfection, or exposure to future variants of this ever-evolving virus.
“We should start thinking about the next variant that’s going to come along rather than worrying so much about BA.2,” she warned.
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.
