A blood donor clinic pictured at a shopping mall in Calgary, Alta., Friday, March 27, 2020. Fewer than 1 per cent of Canadian blood donors in late spring tested positive for COVID-19 antibodies, according to the results of a seroprevalence study that aimed to assess the country’s infection rate of the novel coronavirus. THE CANADIAN PRESS/Jeff McIntosh

Study shows fewer than 1 per cent Canadian blood donors had COVID antibodies

Researchers say antibodies indicate past infection

Fewer than 1 per cent of Canadian blood donors in late spring tested positive for COVID-19 antibodies, according to the results of a seroprevalence study that aimed to assess the country’s infection rate of the novel coronavirus.

Canadian Blood Services and Canada’s COVID-19 Immunity Task Force (CITF) released the findings of the study on Tuesday, based on 37,373 blood samples collected from blood donor centres across Canada except Quebec and the Territories from May 9 to June 18.

The results suggest that by the end of May as few as 0.7 per cent of healthy Canadians had been exposed to SARS-CoV-2, the virus causing COVID-19.

Researchers say antibodies indicate past infection, and can usually be detected within two weeks of the onset of infection.

However, they say the results of the study could underestimate “true seroprevalence” for a number of reasons.

Professor Catherine Hankins, the co-chair of CITF, says antibody levels decline rapidly, and “may have disappeared in some people by the time of testing.”

Hankins also says blood donors are typically more ”health-conscious and healthier” than the general population.

CITF co-chair David Naylor says the current increasing number of COVID-19 cases nationwide suggests a need for continued vigilance.

And while health experts are still unclear on how much, if any, immunity antibodies might provide, Naylor says there is “little to no likelihood” that immunity levels in the population are “high enough to slow down a second wave of COVID-19 infection.

“It’s critical to ramp-up testing and tracing capacity across the country to reduce risk in settings such as workplaces and schools, and to interrupt any chains of transmission quickly to prevent spread,” he added.

The results of the study were broken down by province, showing that P.E.I. and New Brunswick had the lowest seroprevalence at 0 per cent and 0.26 per cent, respectively. Ontario showed the highest with 0.96 per cent.

Quebec’s Hema-Quebec ran its own study on blood donors in the province, which showed the highest seroprevalence in the country at 2.23 per cent.

In individual cities, Ottawa showed the highest percentage of SARS-CoV-2 antibodies with 1.29 per cent seroprevalence, Toronto had 1.07 per cent and Edmonton had 0.38 per cent.

Montreal and Laval showed a seroprevalence of 3.05 per cent in the Hema-Quebec study.

Dr. Graham Sher, CEO of Canadian Blood Services, says its donor base is ”reasonably representative of healthy Canadians between the ages of 17 and about 60.”

READ MORE: B.C. records 429 new COVID-19 cases, two deaths over Labour Day long weekend

The Canadian Press


Like us on Facebook and follow us on Twitter.

Want to support local journalism during the pandemic? Make a donation here.

blood donorCoronavirus

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Some bystanders with fire extinguishers helped keep the fire under control. Photo courtesy Suzie Thomas
Bystanders keep fire from spreading near McIvor Lake turnoff

‘Just be vigilant and careful,’ says Campbell River fire chief

The Pier Street Farmers Market will once again take up residence on Sundays from May to Septmber at the parking lot across from the Community Centre in downtown Campbell River for 2021. Mirror File Photo
Pier Street Farmers Market returns to Cedar Street parking lot for 2021

…and it’s hoped that the addition of artisans this year will make it even better

Some recommendations from the Downtown Safety Select Committee have been approved by Campbell River City Council, including removing the glass stage covering at Spirit Square. Photo by Marc Kitteringham, Campbell River Mirror
Council going ahead with removing Spirit Square stage covering

But mayor acknowledges need for ‘welcoming, warm place with support services’

A small fire on North Rendezvous Island is the first wildfire of the season in the Campbell River area. Officials are asking people to take caution when burning during these dry conditions. BC Wildfire Dashboard
‘Conditions are tricky at the moment’ warns Coastal Fire Centre

Small fire on North Rendezvous Island first of the season for Campbell River area

Rainbow trouts thrashing with life as they’re about to be transferred to the largest lake of their lives, even though it’s pretty small. These rainbows have a blue tinge because they matched the blue of their hatchery pen, but soon they’ll take on the green-browns of their new home at Lookout Lake. (Zoe Ducklow/News Staff)
VIDEO: B.C. lake stocked with hatchery trout to delight of a seniors fishing club

The Cherish Trout Scouts made plans to come back fishing soon

For Leela Harrop, the recent death of her brother Raju Tiwari pushed her to sign up for the vaccine. Photo supplied
Island woman on fence about vaccine prompted by brother’s death

Leela Harrop of Comox says she did have issues with signing up online this past week

Royal Inland Hospital in Kamloops. (Dave Eagles/Kamloops This Week file photo)
RCMP intercept vehicle fleeing with infant taken from Kamloops hospital

The baby was at the hospital receiving life-saving care

Vancouver Police Const. Deepak Sood is under review by the Independent Investigations Office of B.C. after making comments to a harm reduction advocate Sunday, April 11. (Screen grab)
VIDEO: Vancouver officer convicted of uttering threats under watchdog review again

Const. Deepak Sood was recorded Sunday saying ‘I’ll smack you’ and ‘go back to selling drugs’ to a harm reduction advocate

Provincial health officer Dr. Bonnie Henry prepares a daily update on the coronavirus pandemic, April 21, 2020. (B.C. Government)
B.C.’s COVID-19 infection rate persists, 1,005 new cases Friday

Hospitalization up to 425, six more virus-related deaths

Premier John Horgan receives a dose of the AstraZeneca COVID-19 vaccine at the pharmacy in James Bay Thrifty’s Foods in Victoria, B.C., on Friday, April 16, 2021. THE CANADIAN PRESS/Chad Hipolito
B.C. Premier John Horgan gets AstraZeneca shot, encourages others

27% of residents in B.C. have now been vaccinated against COVID-19

The Nautical Dog Cafe at Skaha marina is getting its patio ready in hopes Mother Nature will provide where provincial restrictions have taken away indoor dining. (Facebook)
‘A lot of instability’: B.C. restaurants in layoff limbo

As COVID-19 cases stay high, restaurants in British Columbia are closed to indoor dining

Prime Minister Justin Trudeau looks on as Deputy Prime Minister and Finance Minister Chrystia Freeland responds to a question during a news conference on Parliament Hill in Ottawa, Tuesday, Aug. 18, 2020. THE CANADIAN PRESS/Adrian Wyld
Expectations high as Trudeau Liberals get ready to unveil first pandemic budget

The Liberals will look to thread an economic needle with Monday’s budget

John Furlong, Own The Podium board chairman and former CEO of the Vancouver Olympics, addresses a Vancouver Board of Trade luncheon in Vancouver, B.C., on Wednesday November 25, 2015.THE CANADIAN PRESS/Darryl Dyck
John Furlong presents 2030 Winter Games vision to Vancouver Board of Trade

Vancouver and Whistler would remain among host sites because of 2010 sport venues still operational

Most Read