[Schaulustiger]

Regarding your question about if we might accidentally test for flu or other, already existing corona virii:

This was a topic of discussion in yesterday's talk [1] with Dr. Drosten, a virologist who played an important part in the development of the currently used PCR test. He said that there were extensive studies done with hundreds of samples from both flu patients and patients infected with other corona virii and none returned a positive result. The only other positive results were from corona virii that are special to certain animals (bats, some cows IIRC), but none of those are present in humans. So the accuracy of our current PCR test for SARS-CoV-2 seems to be extremely high.

[1] (transcript in German) https://www.ndr.de/nachrichten/info/16-Coronavirus-Update-Wi...

Here's a quick (and slightly condensed) translation of the relevant parts: "There was a big validation study [for the PCR test]. We tested with a big number of patient samples from patients with flu/cold diseases and other corona viruses. Not once did we get a false positive. [...] It is true though that [the current PCR test] would yield positive results against the old SARS corona virus, but that hasn't been confirmed in a human for 16 years. And theoretically, the test would give a positive result on some bat corona viruses, but they do not affect humans."

[graycat]

I was talking in general, a little more specifically about the news media, and not at all about Dr. Drosten.

[graycat]

It's easy to get a low rate of false positives: Just always report no virus found.

So, we care about both false positives and false negatives. Dr. Brix said as much recently.

[Tomte]

Prof. Drosten is the chief virologist at Berlin Charité.

I'm confident that somewhere in his medical education the concept of false negatives came up, and I'm also certain that he doesn't word his answers in an interview for the general public to the standards of the nitpicking HN population.