By GILLIAN SLADE on August 1, 2020.
Canadian Blood Services routinely tests donated blood for diseases such as HIV and hepatitis, and although COVID-19 is not transmitted by blood, samples are being tested for COVID antibodies.
This is helping to determine how many people have already had COVID-19 and perhaps did not even know it.
“We are in a good position as a blood operator who sees over a million samples per year, to help out policy makers and the provincial government to get a sense of how many people have had the virus,” said Dr. Chantale Pambrun, centre for innovation director for CBS.
Some of the blood from donors – chosen at random and based on availability – is tested for the COVID-19 antibody, “which is an indicator of past infection,” said Pambrun.
Those blood samples that are sent to the research laboratory for testing, are taken from a small amount of blood that is available for testing. No additional blood is taken just for testing, she said, and all personal identification is removed before being sent to the research laboratory.
“A preliminary result that was recently received … showed that less than one per cent of blood donors tested positive (for COVID antibodies),” said Pambrun, pointing out that this is consistent with results from Ontario and B.C.’s public health departments.
Some of those in that one per cent will have known that they already had COVID and have recovered, while others may have no idea they had it. CBS does not notify those who were positive.
“We are not (notifying those testing positive) at this time. Part of our study … was not to further understand that individual,” said Pambrun.
There are studies that are doing that and contacting the individual to determine whether they already knew and can provide additional information on when they think they may have had COVID and what their symptoms were, said Pambrun.
“Our study is looking more on an aggregate level … rather than one individual’s response,” she said.
CBS is widening its study, with results expected later this summer that could shed light on trends in different provinces and regions, and even the age demographics and differences between genders revealed from the tests.
“Further analysis to try to understand all the differences in different health units and mitigation steps in public health guidelines that made a difference to the prevalence,” said Pambrun
She says this could be valuable if there is a second wave of COVID-19 across the country.
It should be noted that the type of screening that takes place on all donated blood, to test for diseases transmitted by blood, is identifiable to the donor in case an intervention is required before that blood is distributed, said Pambrun.