Some B.C. residents are waiting to be tested, not for COVID-19 but the antibodies created by the immune system to protect against it.
Health Canada has not yet approved a “serology” or antibody test for determining if people have had an immune system response to the coronavirus, but the search is narrowing down, B.C. provincial health officer Dr. Bonnie Henry says.
“There are a couple of good candidates that the B.C. Centre for Disease Control is working on, two in particular,” Henry said in her May 9 briefing. “They are in the midst of testing people who we know had this illness and looking at the antibody test and looking at the antibody levels and how well the test performs, so validating the test.”
Reliable antibody testing would determine what Henry calls “community immunity,” picking up on people who contracted COVID-19 and recovered, in some cases without knowing it.
Antibody testing is of great interest around the world, to determine what immunity a person may have after recovering from COVID-19, and how long it may last. The Lancet, a leading British medical journal, reported in April that U.S. authorities gave the green light for drug companies to start selling tests, on condition they withdraw them from the market if their results aren’t up to standard.
One Canadian test group is people who tested positive for COVID-19 at Lynn Valley Care Centre, the first B.C. senior home to record an outbreak, Henry announced in late April. At that time there were 17 different antibody tests being validated, after initial deployment of antibody testing in the U.S. resulted in false positive and false negative results that invalidated their findings.
Health Canada has restrictions on what tests can apply for validation, and is not accepting home or self-test products.
“I have to say, for all of us across the country, it’s a bit of a frustrating process because the tests are not as good as we would hope them to be,” Henry said. “So what we look for is how well they detect people who have the virus and how well they determine people that don’t have the virus. That’s what we call sensitivity and specificity.”
A Canadian expert panel has been set up to look at the immune effects of SARS-CoV-2, the virus that causes COVID-19.