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

West Coast General Hospital in Port Alberni received some good news about an expansion to its emergency department on Jan. 15, 2021. (SUSAN QUINN/ Alberni Valley News)
B.C. health ministry commits $6.25M to hospital expansion in Port Alberni

Plans for larger emergency department have been on hold since 2015

A Tla-o-qui-aht First Nation guardian took this photo of dozens of vehicles parked along a forest service road in the Kennedy watershed. (Submitted photo)
Alberni-Clayoquot Regional District looks at enforcement of illegal camping

ACRD currently does not have an existing bylaw service to tackle the issue

Ucluelet local Geoff Johnson snapped this photo of a Risso’s dolphin that washed up near Chesterman Beach in Tofino on Wednesday, Jan. 13. (Geoff Johnson photo)
Washed up Risso’s dolphin offers glimpse into “whole other world” near Tofino

“It’s like a UFO crash landed and you can come look at it.”

(B.C. government)
POLL QUESTION: Would you report a neighbour in breach of COVID-19 regulations?

Would you report a neighbour in breach of COVID-19 regulations? READ MORE:… Continue reading

Keith the curious kitten is seen on Nov. 4, 2020 at the Chilliwack SPCA. Friday, Jan. 22, 2021 is Answer Your Cat’s Questions Day. (Jenna Hauck/ Chilliwack Progress file)
Unofficial holidays: Here’s what people are celebrating for the week of Jan. 17 to 23

Answer Your Cat’s Questions Day, Pie Day and International Sweatpants Day are all coming up this week

(Phil McLachlan - Capital News)
‘Targeted’ shooting in Coquitlam leaves woman in hospital

The woman suffered non-life threatening injuries in what police believe to be a targeted shooting Saturday morning

JaHyung Lee, “Canada’s oldest senior” at 110 years old, received his first dose of the COVID-19 vaccine on Thursday, Jan. 14, 2021. He lives at Amenida Seniors Community in Newton. (Submitted photo: Amenida Seniors Community)
A unique-looking deer has been visiting a Nanoose Bay property with its mother. (Frieda Van der Ree photo)
A deer with 3 ears? Unique animal routinely visits B.C. property

Experts say interesting look may be result of an injury rather than an odd birth defect

Standardized foundation skills assessment tests in B.C. schools will be going ahead later than usual, from Feb. 16 to March 12 for students in Grades 4 and 7. (Black Press Media file photo)
B.C. teachers say COVID-affected school year perfect time to end standardized tests

Foundational skills testing of Grade 4 and 7 students planned for February ad March

Sooke’s Jim Bottomley is among a handful of futurists based in Canada. “I want to help people understand the future of humanity.” (Aaron Guillen - Sooke News Mirror)
No crystal ball: B.C. man reveals how he makes his living predicting the future

63-year-old has worked analytical magic for politicians, car brands, and cosmetic companies

Terry David Mulligan. (Submitted photo)
Podcast: Interview with longtime actor/broadcaster and B.C. resident Terry David Mulligan

Podcast: Talk includes TDM’s RCMP career, radio, TV, wine, Janis Joplin and much more

Seasonal influenza vaccine is administered starting each fall in B.C. and around the world. (Langley Advance Times)
After 30,000 tests, influenza virtually nowhere to be found in B.C.

COVID-19 precautions have eliminated seasonal infection

Prime Minister Justin Trudeau listens to a question during a news conference outside Rideau cottage in Ottawa, Friday, January 8, 2021. THE CANADIAN PRESS/Adrian Wyld
Trudeau says Canada’s COVID vaccine plan on track despite Pfizer cutting back deliveries

Canadian officials say country will still likely receive four million doses by the end of March

Most Read