So, an update on this. I track the scientific publications on Covid 19 pretty carefully, and tonight I actually read the report referenced in the news item above. It's newly listed on a "science library" web page from the US CDC, and it's been curated for publication, although it's not a "CDC publication". They're providing it as a convenience.well maybe someone was right after all.....
Does This Study Shift the Covid-19 Narrative About When the Virus Was in the US? (townhall.com)
In the study, the Red Cross provided blood samples from donors dated from December 13, 2019 to January 17th 2020 for antibody testing. Sure enough, a number of these samples had antibodies - disease prevention cells - that reacted to the Covid 19 virus. The thing is, the article itself says that they don't know if the antibodies are from Covid 19 or from some other virus with a similar structure (flu, colds, whatever). So while it's interesting, it's not a convincing smoking gun. And then, as if it's not shaky enough already, it gets worse. In another article on the same curated list tonight, a similar study looking at blood samples from 2011 to 2018 also found antibodies that reacted to the Covid 19 virus. It's pretty safe to say that Covid 19 wasn't around in 2011 or 2018, so those antibodies are definitely from something else. It's entirely possible that the same non-Covid antibodies were detected in the 2019-2020 samples. At this point, the science is good enough to say that reactive antibodies are present, but not good enough to say what caused them.
So, the real science says that the data is ambiguous. The sad and annoying thing is that the author of the news item says "and it shows a presence of the coronavirus in samples dated from December 2019". Talk about double-talk. It shows the presence of a coronavirus (could be the flu from a few years back) but there's no certainty at all that it's the SARS-Cov-2 virus that causes Covid 19. Welcome to the click-bait media "let's get people riled up" strategy.
Of course the interesting question is whether these pre-existing antibodies provide any protection from the Covid virus. The authors of both studies say that there's no solid evidence one way or the other, and if you look more broadly, there are studies on prior viruses and inoculations that say that none of the earlier infections or shots will protect you from Covid. Don't get your hopes up.
Anyway, welcome to the highly uncertain science of a novel virus that the world has never seen before - things that you think you know today get upended every week by new data.