Brenner writes: "Hi, TWIV team. Long-time listener. I started in academics after a PhD and a post-doc. I went into public health. I hear in the podcast that there isn't much information on the current COVID-19, or as I prefer to call it, SARS-2-CoV test [Ed. note: CDC seems to be calling it SARS-CoV-2], so let me give you the background. ... The CDC originally came out with a real-time reverse transcription PCR RTRTPCR. It had three targets, all in the N-gene. Why the N-gene when everybody else uses Spike? Your guess is as good as mine. And she gives a link. They sent out ... they sent the test out to 99 different public health labs. Of the 99, only five could make the assay work. 94 labs ... could have the N3 probe react to something in the HSC late in the reaction, causing a late positive CT for the HSC probe two [too?]. That's getting a little dense. Basically, ... test didn't work. They got false positives. The CDC said they were gonna replace just the N3 primer probe set, but that the other two should be good to go.Update 2020-03-21: Rereading this, I came to the incredible realization that there were not two but three weeks before the test could be properly performed. Insane.
A week passed. The CDC was still working on it. Were they going to change the sequence? No one knew what the problem was. However, in situations like this, laboratories cannot just adjust a protocol. We are required by CLIA, FDA, and just about every other alphabet soup agency to do the test as it is written.
A second week passed, and in a very surprising turn of events, the [Association] of Public Health Laboratories, who work very closely with the CDC getting a myriad of assays and programs up and running, wrote a harsh letter to the FDA asking them to loosen requirements for emergency authorized testing. Days afterwards, the CDC said, you only had to use the first two N-primer probe sets. They remanufactured and sent new lots out to the labs in about a week. Basically, we never speak of the N3 primer probe again....
Wednesday, March 18, 2020
From The Virology Trenches: Squandered Chances By The FDA and CDC
A pretty good story from the trenches (written by someone at a local public health agency) regarding the early days of the CDC and FDA in the COVID-19 testing saga, and their role in fumbling the tests. The transcript begins at about 1:25:20; all errors are mine. Italics are what I assume is text from the letter's author; emboldened text is my emphasis, and anything in [square brackets] is my own commentary/editorial simplification as well.
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