Testing for virus antibodies to begin
Cross-country effort aims to determine how many have been infected
Canadian Blood Services is gearing up to start testing for COVID-19 antibodies in the next few weeks, contributing to a massive cross-country study to determine just how many people have been infected with the disease.
Chantale Pambrun, director of Canadian Blood Services’ Centre for Innovation, said the organization partnered with the COVID-19 Immunity Task Force in the spring. The task force was set up by the federal government to co-ordinate efforts around understanding immunity, and includes researchers from across the country.
The blood banks have been saving samples from people who donated in the past few months, which they can rapidly test to inform the task force.
“It’s a really great opportunity for blood donors today who have come through the doors in the last few months to contribute to this data,” she said, “to understand, what has COVID done to Canadians.”
The antibody tests don’t show whether someone has COVID-19, like the nasal swab tests. They instead show whether someone has had it in the past and recovered.
Canadian Blood Services will also test donors going forward, to help the task force get to the goal of at least1million samples. Héma-Québec, the non-profit that supplies blood in Quebec, will also support the project, a spokesperson confirmed.
A similar study in the United States that looked at samples from blood banks and collected in labs for other tests found the number of Americans infected with the coronavirus is 10 times higher than thought, about 23 million people. That’s about five-to-eight per cent of the population, but still means more than 90 per cent is still susceptible, the head of the CDC announced Thursday.
The antibody tests find people who didn’t have symptoms or only had mild ones and weren’t counted in official testing totals because they never got the nasal swab test.
Taking the blood samples won’t involve having to stick an extra needle in a person’s arm, but are done “in the background,” Pambrun said, with samples they normally hold for testing of blood-borne diseases such as HIV and hepatitis, to provide the task force with “an aggregated view of the results for them to then plug those results into a bigger data set.”
For about 80 per cent of donors, there’s enough blood left over after safety testing to test for the antibodies, she said.
They don’t test for active COVID-19 because it’s not spread through blood, Pambrun added.
The federal government has already ordered 140,000 antibody tests from Abbott Laboratories for the study, Federal Procurement Minister Anita Anand told reporters on a recent press call.
“These kits will play an important role in tracking how widely the virus has spread,” she said. “Information made available through these kits could also prove valuable in the estimation of potential immunity and vulnerabilities in our population.”
There’s been some controversy with accuracy of antibody tests in the U.S., but the Abbott test is one of a handful approved by Health Canada.
The task force will roll out several studies over the next two years, said Dr. Tim Evans, director of the School of Population and Global Health at McGill University, who’s leading its secretariat.
They will also look at trends in specific populations such as seniors and pregnant women, and occupational groups like long-term-care home workers and employees at meat packing plants.
The goal is to get “an understanding of the level of infection across the country,” he said, and eventually “understand also through the antibody test what the levels of immunity are, and what their duration will be and what level of protection they provide with respect to risk of further infection.”
The approved tests have “very low false-positive rates,” he said.
Pambrun said they will not be informing donors if they have the antibodies, as the science on immunity is still developing, through studies like those being undertaken by the task force.
“The balance that we have is we don’t want to give people false assurance that you won’t get COVID-19 again because we don’t know that,” she said.
“But we are keeping on top of what the evidence shows and how informative this could be to donors.”
Ministry of Health spokesperson Hayley Chazan told the Star earlier this month that a framework for incorporating these serology tests into the province’s wider testing strategy is expected to be released shortly.
In the meantime, the Health Canada-approved antibody tests are currently licensed only for research, and individuals can’t go out and get them if they want to know if they’ve been infected.