Infection more than once by sub-variants in the Omicron family seems possible, but seems rare, scientists in Denmark found in a recent real-world study — reassuring countries that countries will not experience another sudden surge of infection.
Early research that was Posted online As a preliminary print Tuesday and not yet peer-reviewed, it included an analysis of recent SARS-CoV-2 infections by a team from the Serum Statins Institute (SSI), a Danish public health institute.
Many of these were the highly contagious BA.2 variant, which is now prevalent in that country—and on the rise elsewhere—after pressure on other Omicron subvariants characterized by various mutations, including the original lineage, as well as BA.1, BA. 1.1 and BA.3.
Of the nearly two million infections recorded in Denmark between mid-November and mid-February, the researchers focused on those who tested positive twice with an interval of 20 to 60 days, and whose infections had undergone previous genetic monitoring and were classified as specific. Follow.
Less than 1,800 people responded to these criteria, and a subset of nearly 1,000 samples was randomly selected for sequencing.
The team ended up finding 187 cases of re-infection, including 47 cases in which BA.2 infection occurred shortly after infection with BA.1, “mostly in non-immunized individuals with mild disease that does not lead to hospitalization or death”, As the team wrote.
One of the researchers, Dr. Trolls Liebeck, chair of the Danish SARS-CoV-2 Variant Evaluation Committee, told CBC News that this provides the first evidence of re-infection among members of the Omicron family, but that this appears to be a “very rare phenomenon.”
“If it’s a big problem to be able to pick up BA.2 after BA.1, you can imagine a new wave,” he said.
“That doesn’t really point in that direction.”
BA.2 Cases Rise in Canada
After weeks of uncertainty, it’s a welcome finding, after an upward spike in BA.2 cases in several countries sent scientists scrambling to understand whether the highly mutated variant could extend this year’s Omicron wave — or even launch a new one.
In Denmark, BA.2 infections now account for nearly nine out of 10 cases, with cases also rising in countries such as Norway, South Africa and the United Kingdom.
Here in Canada, the alternative was barely a snapshot in federal data by early January, but the latest data available by the end of the month suggests that It makes up about 1 in 10 caseswith the continuing accumulation of recent data.
Its rise comes as the overall Omicron wave recedes, and while much of the country is easing or dropping COVID-related restrictions altogether, it is giving Canadians an opportunity to socialize at home more freely than at many points during this more than two-year pandemic.
The virus will still circulate, said Dr. Zane Chagla, an infectious disease specialist and professor at McMaster University in Hamilton, Ontario, but based on emerging evidence about how BA.2 works, Canada is unlikely to experience another wave of infection. linked to this alternative.
This is partly due to Canada’s high vaccination rate, he said, combined with the sudden rise in exposure caused by the original Omicron surge that has infected large numbers of Canadians in recent months, Providing millions with hybrid immunity against this advanced virus.
Angela Rasmussen, a virologist with the University of Saskatchewan Vaccines and Infectious Diseases Organization (VIDEO) said.
Questions about the severity of the disease
While its potential for transmission and re-infection is becoming more apparent, there are still questions about the level of serious illness that BA.2 can cause.
The World Health Organization noted on Tuesday that factual data on clinical risk from South Africa, the United Kingdom and Denmark, where immunity to vaccination or natural infection is high, show no reported difference in severity between BA.2 and BA.1.
“Now, that could change as BA.2 pushes out BA.1 and makes its way to higher risks [unvaccinated] People,” noted Jason Kendracchuk, associate professor of medical microbiology and infectious diseases at the University of Manitoba, in an email with CBC News.
Initial preliminary lab results from a team in Japan using hamster models—which allowed researchers to infect people who had no previous immunity—suggested that BA.2 might cause more serious disease than BA.1 in those who had not previously received a viral or viral vaccination. infection.
the findings, Recently Posted online As a prior reference, it indicates that the rapidly spreading subvariable may be closer to the previous variants in terms of disease severity.
But Rasmussen, of VIDO in Saskatchewan, stressed that animal studies do not paint a complete picture of how pathogens such as SARS-CoV-2 affect humans.
And while scientists should continue studying BA.2, she said the greater focus should be on increasing vaccination rates and uptake of the booster vaccine to give people the best chance of fending off potential infection — whether it’s a re-Omicron infection, or exposure to future variants of this ever-evolving virus.
“We should start thinking about what’s next, rather than worrying so much about BA.2,” she cautioned.