Experts are concerned some people are being ordered to isolate who are no longer infectious or a threat to public health
To understand the latest wrangle over COVID-19 testing, think of trying to identify a single person from a photo of a stadium packed with tens of thousands — a kind of Where’s Waldo hunt.
The gold standard test used to detect the wily virus that causes COVID-19 works much the same way, by searching for miniscule pieces of viral genes from cells and mucus swabbed from someone’s nose. If a trace amount of the virus’ genetic material is detected, it’s amplified, or copied, over and over again, cycle after cycle, each cycle doubling the amount of material and making millions of copies of what you’re looking for — your Waldo.
The concern is that some people are being ordered to isolate who are no longer infectious or a threat to public health, and that provinces are encouraging mass testing using a hyper-sensitive test that’s churning out daily cases numbers, the implication being that a case always equals an active infection equals a person capable of spreading to others.
“We do know that PCR picks up dead organism that is not infectious,” says Dr. Vanessa Allen, chief of medical microbiology at Public Health Ontario. “I think a lot of the discussion is, do we in fact need a test that’s so sensitive, and what is the meaning of those tests at the very end threshold? Are they actually the people we need to isolate?”
Sharon Kirkey – National Post – October 2, 2020.