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

The Thornhill Volunteer Fire Department responded to an engine Dec. 3 on Highway 16, using a compressed air and foam solution to extinguish the flames. (Submitted Photo/Krista Bowman)
Semi truck engine catches fire in Thornhill

Firefighters used a compressed air and foam solution to put out the fire

A volunteer committee is urging the provincial government to complete grizzly habitat mapping. (Ivan Hardwick photo)
Volunteer committee urges province to complete grizzly habitat mapping

Committee says only 18 of 37 watersheds have been mapped, province has spent $500,000 so far

A coal-fired power plant seen through dense smog from the window of an electric bullet train south of Beijing, December 2016. China has continued to increase thermal coal production and power generation, adding to greenhouse gas emissions that are already the world’s largest. (Tom Fletcher/Black Press)
LNG featured at B.C. energy industry, climate change conference

Hydrogen, nuclear, carbon capture needed for Canada’s net-zero goal

Terrace RCMP arrested an impaired driver and found illicit drugs, weapons and stolen property in the vehicle on Nov. 28, 2020. (File Photo)
Terrace RCMP arrest impaired driver in possession of weapons

Weapons, illicit drugs, stolen property found in vehicle

A COVID-19 exposure has been recorded at Centennial Christian School in Terrace. The exposure occurred between Nov. 23 and Nov. 26, 2020. (Centennial Christian School Facebook photo)
COVID-19 exposure recorded at Centennial Christian School in Terrace

It’s the first known school exposure in Terrace

Motorists wait to enter a Fraser Health COVID-19 testing facility, in Surrey, B.C., on Monday, Nov. 9, 2020. THE CANADIAN PRESS/Darryl Dyck
Another 694 diagnosed with COVID-19 in B.C. Thursday

Three more health care outbreaks, 12 deaths

A demonstrator wears representations of sea lice outside the Fisheries and Oceans Canada offices in downtown Vancouver Sept. 24, demanding more action on the Cohen Commission recommendations to protect wild Fraser River sockeye. (Quinn Bender photo)
First Nations renew call to revoke salmon farm licences

Leadership council implores use of precautionary principle in Discovery Islands

Ten-month-old Aidan Deschamps poses for a photo with his parents Amanda Sully and Adam Deschamps in this undated handout photo. Ten-month-old Aidan Deschamps was the first baby in Canada to be diagnosed with spinal muscular atrophy through Ontario’s newborn screening program. The test was added to the program six days before he was born. THE CANADIAN PRESS/HO, Children’s Hospital Eastern Ontario *MANDATORY CREDIT*
First newborn tested for spinal muscular atrophy in Canada hits new milestones

‘If Aidan had been born any earlier or anywhere else our story would be quite different’

(Pixabay)
Canadians’ mental health has deteriorated with the second wave, study finds

Increased substance use one of the ways people are coping

An RCMP officer confers with military rescuers outside their Cormorant helicopter near Bridesville, B.C. Tuesday, Dec. 1. Photo courtesy of RCMP Cpl. Jesse O’Donaghey
Good Samaritan helped Kootenay police nab, rescue suspect which drew armed forces response

Midway RCMP said a Good Samaritan helped track the suspect, then brought the arresting officer dry socks

People line up at a COVID-19 assessment centre during the COVID-19 pandemic in Scarborough, Ont., on Wednesday, December 2, 2020. Toronto and Peel region continue to be in lockdown. THE CANADIAN PRESS/Nathan Denette
COVID-19 vaccine approval could be days away as pressures mount on health-care system

Many health officials in regions across the country have reported increasing pressures on hospitals

(Needpix.com)
Pandemic has ‘exacerbated’ concerns for B.C. children and youth with special needs: report

Pandemic worsened an already patchwork system, representative says

Most Read