Coronavirus anti-body blood tests reveal ‘undetected infections’

Canada’s COVID-19 Immunity Task Force and Canadian Blood Services said that of the 10,000 samples that have been tested, under one percent have been positive for SARS-CoV-2 antibodies. These antibodies are found in people who have already recovered from the virus.

Dr. Catherine Haskins said that since over 99 percent of the blood samples that were donated do not have antibodies to protect against SARS-CoV-2, Canadians should be weary as the country begins to reopen.

"By far, the majority of us remain vulnerable to infection," said Haskins.

"We need to ramp up testing and tracing capacity across the country to interrupt any chains of transmission quickly to prevent unchecked spread.”

In a press release, Dr. David Naylor said that the small percentage is concerning because it means that for each confirmed coronavirus case, there are “several undetected infections.”

As of Thursday, over 112,000 cases of coronavirus have been confirmed in Canada, which represents approximately 0.3 percent of the population.

The samples that were tested were donated from May 9 to June 8, and do not contain samples from Quebec—Canada’s hardest hit province. According to the task force press release, Quebec’s results will be made public “in the near future.”

Canadian Blood Services is still testing the 37,800 blood samples donated in May and June.

Researchers are still unsure as to how long antibodies last after they are generated to fight off the SARS-CoV-2 infection. The New England Journal of Medicine published research this week suggesting that 50 percent of the antibodies vanish after 36 days.