Half of the Canadian population, or more than 17 million people, were infected with Omicron in only five months starting December 2021, local media has reported.
The media outlet quoted a report by the Covid-19 Immunity Task Force (CITF) showing that prior to Omicron, just 7 per cent of Canadians had antibodies from being infected by the virus. The proportion rose by 45 per cent from December 2021 to May 2022, Xinhua news agency reported, reffering to National Post.
According to the report, this increase is equivalent to more than 100,000 infections per day, which is more than 10 times the number of daily cases seen during previous peaks of SARS-CoV-2 waves over the last two years.
The highest level of infection was found in young adults aged 17 to 24, based off of donations made to Canadian Blood Services. A total of 65 per cent of them had antibodies at the end of May, the report revealed.
The results are based on population seropositivity, or “the proportion of people with antibodies to SARS-CoV-2 in their blood”, the report explained, adding that the research differentiated between antibodies that occurred naturally as a reaction to being infected by the virus and antibodies created by the vaccine. They were thus able to determine which antibodies were a sign of past infection “to track the magnitude of the Omicron wave”.
“Omicron has been a tsunami,” CITF Executive Director Tim Evans was quoted as saying. He said that new sublineages of the virus have been spreading since then, pushing the percentage of Canadians who have been infected “well above” 50 percent.
“Millions of Canadians now have hybrid immunity from a combination of Covid-19 vaccines and an infection,” said CITF Co-Chair David Naylor.
“Unfortunately, emerging evidence suggests that most of these individuals remain at risk of re-infection with viruses in the Omicron lineage,” Naylor was quoted by the National Post.
On April 23, 2020, the Canadian government launched CITF with a mandate to catalyse, support, fund and harmonise knowledge on SARS-CoV-2 immunity for federal, provincial, and territorial decision-makers in their efforts to protect Canadians and minimise the impact of the Covid-19 pandemic.