Chief Public Health Officer Dr. Theresa Tam holds a press conference on Parliament Hill amid the COVID-19 pandemic in Ottawa on Wednesday, June 17, 2020. THE CANADIAN PRESS/Sean Kilpatrick

OTTAWA - Blood samples collected from tens of thousands of Canadians will soon be tested for signs of COVID-19 antibodies as the federal government seeks to learn how many people have already contracted the novel coronavirus.

Dr. Theresa Tam, Canada's chief public health officer, said she is excited about the partnership between the national immunity task force and Canada's blood agencies, Canadian Blood Services and Hema-Quebec. Tam is a member of the task force.

The two organizations have already collected "tens of thousands" of blood samples from Canadians that will be used for the initial immunity testing across the country. All they are waiting for is the arrival of the testing kits, which are now on their way.

Federal Procurement Minister Anita Anand said Wednesday a contract is now in place to buy 140,000 serology test kits from Abbott Laboratories. Health Canada approved Abbott's serology test on May 21, but it took several weeks for the procurement process to work its way out.

"These kits will play an important role in tracking how widely the virus has spread," Anand said.

The tests, which look for antibodies created by the human body after exposure to a virus, will help determine who has had COVID-19, which populations are most vulnerable to new outbreaks, whether having it makes someone immune to further illness, and how long that immunity might last.

Knowing those things will guide governments in deciding what public health measures to enforce if, or when, a second wave of COVID-19 begins to arrive in Canada. It can also help guide decisions on who to vaccinate first if a COVID-19 vaccine becomes available.

A study published last month in the Journal of Clinical Microbiology found Abbott's test had only one false positive in more than 1,000 specimens tested, and that it was able to detect the presence of the COVID-19 antibody 17 days after symptoms began.

The immunity task force was established by the federal government in late April to co-ordinate national efforts on immunity detection.

Because some people get COVID-19 but show no symptoms, and because widespread testing for the virus that causes COVID-19 did not become the norm in most provinces until just recently, public health experts acknowledge the number of people who have actually been infected exceeds the number of cases reported.

As of Wednesday more than 99,400 Canadians have tested positive for COVID-19 since the end of January but the immunity task force is charged with working with the provinces to figure out how many cases went undetected.

Health Minister Patty Hajdu said the partnership with the two blood collection agencies provides a great number of samples for the initial survey.

The task force is also working with Indigenous leaders to identify a specific approach to immunity testing in Indigenous communities, said Hajdu. She said the government will provide an update on the work of the task force soon.

Anand also provided a brief update on overall efforts to bring in personal protective equipment in Canada, saying the 70th air cargo shipment of masks, gowns and other devices will land in Canada Wednesday. She said the government is also now turning to container ships to bring in the materials.

Four ships have already docked at the Port of Vancouver, bringing in 500,000 litres of hand sanitizer, and more ships will be arriving over the summer, said Anand.

Canada has now secured and distributed 3.1 million N95 respirators to provinces for use by front-line health staff. There have also been 17 million face shields made, most of them in Canada by companies that retooled their production lines to help meet the needs of the pandemic.

This report by The Canadian Press was first published June 17, 2020.

News from © The Canadian Press, 2020