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

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

An x-ray tech demonstrates the new equipment in use. (Photo Submitted)
New diagnostic equipment now operational at Sylvan Lake AACS

In August it was announced that Stephen and Jacqueline Wuori donated $850,000 to AACS

People skate on a lake in a city park in Montreal, Sunday, January 10, 2021. THE CANADIAN PRESS/Graham Hughes
The end of hugs: How COVID-19 has changed daily life a year after Canada’s 1st case

Today marks the one year anniversary of COVID-19 landing in Canada

SARS-CoV-2 virus particles, which causes COVID-19, emerge from the surface of cells isolated from a patient in the U.S. and cultured in a lab in a 2020 electron microscope image. THE CANADIAN PRESS/AP-HO, National Institute of Allergy and Infectious Diseases - Rocky Mountain Laboratories
Alberta adds 463 new COVID-19 cases on Sunday

The central zone has 818 active cases

As of Friday, Alberta has under 10,000 active COVID-19 cases. (Image courtesy CDC)
Alberta identifies 573 new COVID-19 cases, 13 deaths on Saturday

There are currently 9,727 active cases of the virus in the province

Terrance Josephson of the Princeton Posse, at left, and Tyson Conroy of the Summerland Steam clash during a Junior B hockey game at the Summerland Arena in the early spring of 2020. (John Arendt - Summerland Review)
QUIZ: How much do you know about hockey?

Test your knowledge of Canada’s national winter sport

Red Fraggle, one of Jim Henson Company’s Fraggle Rock characers, is shown at Time To Play Holiday Show, Tuesday, Sept. 28, 2010, in New York. The Jim Henson Company says production has officially started in Calgary on a reboot of the original 1980s children’s puppet series, which was filmed in Toronto.THE CANADIAN PRESS/AP/Mark Lennihan
‘Fraggle Rock’ children’s puppet series reboot starts production in Calgary

A spokesperson says the new series will stream on Apple TV plus

Black Press file photo
Wetaskiwin RCMP investigate fatal pedestrian collision

A 37-year-old man from Maskwacis has died in hospital as a result of his injuries.

A registered nurse prepares a dose of the Moderna COVID-19 vaccine in Halifax on Monday, Jan. 11, 2021. Yukon’s Minister of Community Services, John Streiker, says he’s outraged that a couple from outside the territory travelled to a remote community this week and received doses of COVID-19 vaccine. THE CANADIAN PRESS/Andrew Vaughan-POOL
Couple charged after travelling to Yukon to get COVID-19 vaccine

The maximum fine under the emergency measures act is $500, and up to six months in jail

Metis Nation of B.C. President Clara Morin Dal Col poses in this undated handout photo. The Metis Nation of B.C. says Dal Col has been suspended from her role as president. The Metis Nation of B.C. says Dal Col has been suspended from her role as president. THE CANADIAN PRESS/HO, Metis Nation of B.C. *MANDATORY CREDIT*
Metis Nation of B.C. suspends president, citing ‘breach’ of policies, procedures

Vice-president Lissa Smith is stepping in to fill the position on an acting basis

Prime Minister Justin Trudeau speaks in the in the House of Commons on Parliament Hill in Ottawa on Thursday, Dec. 3, 2020. THE CANADIAN PRESS/Justin Tang
Payette shouldn’t get same benefits as other ex-governors general: O’Toole

Former governors general are entitled to a pension and also get a regular income paid to them for the rest of their lives

A woman injects herself with crack cocaine at a supervised consumption site Friday, Jan. 22, 2021 in Ottawa. THE CANADIAN PRESS/Adrian Wyld
Drug users at greater risk of dying as services scale back in second wave of COVID-19

It pins the blame largely on a lack of supports, a corrupted drug supply

RCMP. (Phil McLachlan - Black Press Media)
Blackfalds RCMP investigate fatal collision

Preliminary investigation revealed a south bound pickup truck collided with an eastbound car

Jennifer Cochrane, a Public Health Nurse with Prairie Mountain Health in Virden, administers the COVID-19 vaccine to Robert Farquhar with Westman Regional Laboratory, during the first day of immunizations at the Brandon COVID-19 vaccination supersite in Brandon, Man., on Monday, January 18, 2021. THE CANADIAN PRESS/Tim Smith - POOL
Top doctor urges Canadians to keep up with COVID measures, even as vaccines roll out

More than 776,606 vaccines have been administered so far

Most Read