More than a quarter of Quebec adults developed COVID-19 antibodies in early 2022, study shows

Héma-Quebec used a test to detect COVID-19 antibodies in donors and compared the result to a pre-Omicron sample from the same people.

Héma-Quebec produced study at request of provincial government

A study from Héma-Québec found that 27.8 per cent of adults in Quebec developed COVID-19 antibodies from January to mid-March. (Ryan Remiorz/The Canadian Press)

More than one in four Quebec adults developed COVID-19 antibodies between January and mid-March of this year, according to a study released Monday by the province's blood services organization.

The study by Héma-Quebec, which was carried out at the request of the province's Health Ministry, used a test that was able to detect COVID-19 antibodies in adult blood donors.

Researchers compared the presence of antibodies to an earlier sample from the same person taken before the arrival of the Omicron variant.

Using samples donated to the province's plasma bank, the organization concluded that 27.8 per cent of Quebec's adult population was infected with COVID-19 in the first 2½ months of the year.

Quebec's interim public health director said on Feb. 23 that nearly three million Quebecers, including more than a third of all children, were believed to have been infected by COVID-19 since the beginning of the Omicron wave in December.

WATCH | How Quebec's blood bank tracked COVID-19 antibodies: 

1 in 4 adult Quebecers infected with COVID-19 during Omicron wave: study

11 months ago
Duration 4:40
Dr. Marc Germain is Héma-Québec's vice-president of medical affairs and innovation

That estimate was based on modelling using hospitalizations that allow authorities to infer the actual number of cases, as well as a serological study conducted by researchers at Sainte-Justine children's hospital in Montreal that estimated that 35 to 40 per cent of Quebec children had COVID-19 as the Omicron variant spread, Dr. Luc Boileau said at the time.

The Héma-Quebec study does not include children because blood donors must be 18 and over.

Meanwhile, Quebec health officials reported four more deaths due to COVID-19 on Monday and a 16-person drop in the number of people hospitalized with the virus.

The total number of COVID-19 hospitalizations sat at 1,910, after 85 people were admitted in the past 24 hours and 101 discharged.

The number of people in ICU held steady at 66.

The number of health-care workers who were absent due to COVID-19 dropped by nearly 1,000 over the weekend, down to 6,357 from 7,337 reported Friday.

The government also reported another 622 new COVID-19 cases detected by PCR test, which authorities say is an underestimation because testing is limited to certain groups.

The official tally of COVID-19 cases in the province on Monday was 1,052,637.