Thought of the Day - July 28 2021 - PCR Testing Again

The US FDA has just announced that they will be phasing out the SARS-CoV-2 PCR test that was hurriedly introduced early in 2020. As reported before, the test was not particularly accurate, having a false negative rate of around 30% ( Thought of the Day - September 21 - Testing ). The FDA admits that this was not really a design flaw but more to do with quality control, especially in the early days ( Thought of the Day - May 4 2021 - PCR Testing Protest ). As a result the failure to detect positive cases was one of the reasons that death rates were much higher in the first wave in the US, than later in the year.

The old test will be phased out by the end of 2021. It is being replaced by new tests that will cover influenza detection as well as COVID. At first there were some false reports saying that the old test could not differentiate between SARS-CoV-2 and influenza, implying it detected positive for both, when in fact the old test was not for the flu at all.

So why the change? Well one of the reasons is Delta variant infection shows different COVID symptoms. Flu-like symptoms, such as runny nose and sneezing, are now more common than say the dry cough of the past. Thus, with traditional North American flu season just a few months away it would be a good idea to distinguish, right? Well for virologists, statisticians and politicians yes, for you and me maybe not so much.

The reason I say that is, especially here in Canada, we have not approved any COVID specific antivirals and thus the treatment regime for influenza is not much different from COVID in the first place. Second, if we start to apply PCR testing more broadly for flu, we will just end up with another case-demics ( Thought of the Day - September 20 - By the Numbers ). This fall we could introduce a "flu-demic" as we come to identify flu carriers; these people will now be said to have "asymptomatic flu".

Of course pharma companies are rubbing their hands together. They have been trying for years to find a way to boost the use of the seasonal flu vaccine. Indeed while I am not an anti-vaxxer, I am not a big fan of repeat vaccination. While the percentage of severe side-effects in healthy people are varnishy small, to misquote Hunter S. Thompson "You buy the ticket, you take the ride". The more times you get vaccinated the more times you take the chance something could go wrong; even more true in countries like Canada who, in order to improve "patient comfort", do not aspirate ( Thought of the Day - March 25 2021 - Are We Doing Vaccinations Wrong? ).

Cheers

Cliff