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

Qualicum Beach roundabout project would cost nearly $2M

Town to apply for funds to cover $1.79M of the total

Town of Qualicum Beach defers discussions with preservation society regarding wetlands

CAO says registered covenant will protect land in perpetuity

Qualicum Beach seek funds for $4.5M community field project

Turf surface would allow for new sporting activities

Parksville homeowner must clean up property or face penalties

If deadline not met, city crews will do the job and a bill will be sent out

B.C. reports 122 new COVID-19 cases as health officials urge smaller social circles

Health officials urge against shaming and blaming patients

Emaciated grizzly found dead on central B.C. coast as low salmon count sparks concern

Grizzly was found on Gwa’sala-‘Nakwaxda’xw territory in Smith Inlet, 60K north of Port Hardy

VIDEO: B.C. to launch mouth-rinse COVID-19 test for kids

Test involves swishing and gargling saline in mouth and no deep-nasal swab

Young Canadians have curtailed vaping during pandemic, survey finds

The survey funded by Heart & Stroke also found the decrease in vaping frequency is most notable in British Columbia and Ontario

B.C. teachers file Labour Relations Board application over COVID-19 classroom concerns

The application comes as B.C.’s second week of the new school year comes to a close

CHARTS: Beyond Metro Vancouver, COVID-19 cases in B.C. haven’t increased much recently

COVID-19 case counts outside of Metro Vancouver have been level since July

70-year-old punched in the head in dispute over disability parking space in Nanaimo

Senior’s turban knocked off in incident at mall parking lot

Thousands of child care spaces coming to 35 B.C. communities

Province announces milestone in Childcare BC plan

Most Read