Update–A reader suggested that I be a little more clear about PCR testing. While PCR tests are sometimes used to detect proteins, in the CV-19 case they are aimed at detecting viral RNA. A PCR test has a “primer” which is sequence of molecules designed to match up with part of the RNA in the virus. In humans, there is DNA, which carries the sequences to make a variety of proteins which serve various purposes. The DNA is actually translated into a molecule called RNA, which is then “read” by a cell’s protein making machinery to create the proteins. A virus does not have DNA, it uses RNA to directly create proteins. Oddly enough, the PCR test turns the viral RNA into DNA, because PCR tests were originally developed to match DNA and then replicate the DNA sequence. A positive test occurs when a threshhold number of copies of DNA exist. The number of replication cycles it takes to reach that threshhold is a critical number because it can help identify how much virus was present. Lower cycle numbers mean more virus. If you use higher cycle numbers, you are potentially recognizing very small amounts of viral RNA. Hope this isn’t too technical. And it is still pretty simplified.
My God, some semblance of journalism lives at the New York Times. This story is what many of us have suspected, but lack access to get proof. There are really serious problems both with the use of PCR tests and with the interpretation of the results as “positive”. (NY Times Story) The PCR test is a way of determining if there is virus present in a person. Because it really only detects RNA fragments, it tells you nothing about whether the virus is viable or whether the person is infectious. The PCR test used for CV also gives no information about viral load. So many positive test results merely reflect the presence of some RNA fragments. The person may never have actually been infected, and according the Times analysis, many positive results are actually very borderline and involve very low amounts of virus (again, just RNA fragments).
Based on cycle times, the technical way a PCR test would tell you how much virus (again, really just RNA fragments) is present, the Times found that 90% of positive samples in New York, Massachusetts and Nevada were barely positive. They represent people who are almost certainly not infectious. Every expert the Times talked to said the tests were too sensitive and the threshhold for positivity needed to be raised, otherwise time is wasted contact tracing from people who couldn’t possibly have caused transmission. And those people are needlessly told to quarantine.
Of course the Times spins all this to mean that we need even more testing, just of a different kind. Here is the real message: we have tons of people who were exposed to the virus and cleared it immediately with no real infection and without being infectious. This is almost certainly due to adaptive immunity from prior seasonal coronavirus infections or innate immunity mechanisms. There is no other possible explanation. That is incredibly good news and once again, demonstrates how pointless our approach to a largely harmless pathogen has been. Imagine all the damage we have done because of this, including killing many people and worsening the health of many others.
Bring this home to the state of Minnesota. The state told us today there were 1000 new cases reported. Not really, there were at most around 100 cases in people who might actually be infectious. Here is another practical example–all those cases in primary, secondary and college, I would absolutely bet that those are 99% not real positive, in the sense of infectious, cases. Open up the schools and stop screwing around pretending we actually even have an epidemic.
And as if PCR tests weren’t in enough trouble, an updated version of a paper from April (Medrxiv Paper) details the issues with false positives from those tests. The authors essentially chastise policymakers and epidemiologists for relying on a single positive test result when it is known that PCR tests have serious accuracy problems. The authors explain in a variety of scenarios just how misleading even a few false positives can be. The entire process of a PCR test, in addition to the cycle threshhold issue described in the Times story, creates potential for mishandling, contamination, and false results. When you are rushing to do millions of tests, the likelihood of screwups is greatly enhanced. The authors further call for immediate steps to reduce false positives and suggest that no test should be deemed to have a positive result unless it is confirmed by a second testing. Oh, great. Even more testing.
What a mockery of a rational process this entire epidemic episode has been.