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

Local Skeena candidates for the Oct. 24 snap election

Current BC Liberal MLA Ellis Ross will be running again, as will Nicole Halbauer for BC NDP

Unofficial holidays: Here’s what people are celebrating for the week of Sept. 20 to 26

Rabbit Day, Hobbit Day and One-Hit Wonder Day are all coming up this week

What is the future of transportation in Terrace?

Active transportation, transit, road networks to play a big part in the coming years

Single-engine aircraft crashes near Telkwa

Two occupants of the plane sustained minor injuries and were transported to hospital

Terrace firefighters heading south to help battle wildfires in Oregon

Over 200 B.C. firefighting personnel will assist in the U.S.

COVID-19: 4 more deaths, 366 new cases in B.C. since Friday

A total of 8,208 people in B.C. have tested positive for COVID-19 since January

Group wants Parliament, courts to hold social media to same standard as publishers

Daniel Bernhard made the comments shortly after Friends of Canadian Broadcasting released a research paper

B.C.’s Chase Claypool catches first NFL touchdown pass

Abbotsford grad establishes new record for longest scrimmage TD by a Canadian

B.C. has highest number of active COVID-19 cases per capita, federal data shows

B.C. currently has 1,803 active cases after weeks of COVID-19 spikes in the province

Join Black Press Media and Do Some Good

Pay it Forward program supports local businesses in their community giving

181 days gone: Family continues to look for man last seen in RCMP custody 6 months ago

Brandon Sakebow’s last known location was leaving Mission RCMP cell, police say; family has doubts

B.C. unveils new cannabis sales programs to help small, Indigenous growers

Government did not say how it will define small producers, but says nurseries will be included in the policy

B.C. transportation minister will not seek re-election

Claire Trevena has held the position since 2017

Most Read