03-09-2020, 06:08 PM
I believe I recall somebody on this thread complaining that the US didn't use the "WHO test" for COVID-19. I can't find that post now, but in any case I think it is real interesting to look at https://www.who.int/emergencies/diseases...y-guidance. It shows what many, but not all (no Korea and no Italy) are using for testing. As expected, while there are common elements, all the tests are different. This is an example of the old saying that if you give a problem to N experts you will get 2 ** N solutions. The WHO suggests that countries that are not sure of themselves send the first 5 positive tests to the WHO for validation, but they don't disclose their own test, at least on this web page.
All these testing protocols have their strengths and weaknesses for sure. As the WHO points out, none of them are "validated". It is clear the CDC was worried about false positives and wanted a smaller target than the entire N gene. That may have been a wise decision, but they messed up the execution. I would imagine that each nation took into account what primers it could obtain quickly in adequate quantity that were clinical grade etc. That could lead to different approaches all by itself. This list doesn't include the different protocols developed at Stanford and other such institutions.
Some have called for "listening to the scientists". However, as the varied test show, science speaks with many sometimes disparate voices. Further, the CDC problem was more bio-engineering than science. The test may have been fine, the execution was not.
All these testing protocols have their strengths and weaknesses for sure. As the WHO points out, none of them are "validated". It is clear the CDC was worried about false positives and wanted a smaller target than the entire N gene. That may have been a wise decision, but they messed up the execution. I would imagine that each nation took into account what primers it could obtain quickly in adequate quantity that were clinical grade etc. That could lead to different approaches all by itself. This list doesn't include the different protocols developed at Stanford and other such institutions.
Some have called for "listening to the scientists". However, as the varied test show, science speaks with many sometimes disparate voices. Further, the CDC problem was more bio-engineering than science. The test may have been fine, the execution was not.