Surprised no one linked this earlier - Printable Version
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Surprised no one linked this earlier - teejers1 - 11-16-2020
https://www.businessinsider.com/coronavirus-emerged-italy-september-of-last-year-study-shows-2020-11
I know some folks in these parts were wedded to a Covid starting point in the US of end of January/beginning of February. [Never sure why people were so adamant on this point - it never struck me as particularly important - much more important to deal with what we were confronted with, regardless of when it first arrived].
Anyway, September 2019 in Italy is interesting. If this is accurate, is there any reason to believe that the virus was not also present in the U.S. in 2019?
RE: Surprised no one linked this earlier - magnus - 11-16-2020
Thanks for the link, teejers1.
I too am curious how some of the experts might explain this away.
Was it a mutation that made it more virulent? Or is there some other coronavirus that might be less dangerous but cause antibodies that are able to also combat SARS-COV2. Or something else?
RE: Surprised no one linked this earlier - dabigv13 - 11-16-2020
Antibodies against SARS-COV2 have been found in many different populations in samples collected over several years prior to Jan 2020. These are thought to represent antibodies to different coronaviruses that also cross react with the spike epitope of SARS-COV2.
Covid19 was not in Italy last September. If it was, they would have had a brobdingnagian outbreak then, and not in April.
RE: Surprised no one linked this earlier - BostonCard - 11-16-2020
Here's the paper they reference:
https://journals.sagepub.com/doi/full/10.1177/0300891620974755
I don't want to dismiss it out of hand, but my best guess is that their "proprietary SARS-CoV-2 binding" test had poor specificity and that these were cross reactions. However, if this is replicated with validated test with known specificity then it would change our understanding of where and when the virus emerged. Certainly the Chinese have tried to deflect blame by saying it came from Italy.
And yes, if the virus emerged in Italy in September 2019, then I would expect that it was in the US by October 2019 at the latest.
BC
RE: Surprised no one linked this earlier - DocSavage87 - 11-16-2020
(11-16-2020, 04:38 PM)BostonCard Wrote: Here's the paper they reference:
https://journals.sagepub.com/doi/full/10.1177/0300891620974755
I don't want to dismiss it out of hand, but my best guess is that their "proprietary SARS-CoV-2 binding" test had poor specificity and that these were cross reactions. However, if this is replicated with validated test with known specificity then it would change our understanding of where and when the virus emerged. Certainly the Chinese have tried to deflect blame by saying it came from Italy.
And yes, if the virus emerged in Italy in September 2019, then I would expect that it was in the US by October 2019 at the latest.
BC
Agree that it seems likely due to poor specificity given the time course of the outbreak in Italy. They were using anti-SARS-CoV-2 RBD Ab detection.
I believe the "proprietary SARS-CoV-2 binding test" they referred to was described in their earlier paper:
https://www.biorxiv.org/content/10.1101/2020.08.10.243717v1.full.pdf
I noticed in a recent Nature paper (https://www.nature.com/articles/s41421-020-00224-3) this blurb:
Quote:We also tested whether antibodies from COVID-19 patients cross-reacted with antigens from other CoV. We performed ELISA using plasma from the same patients with SARS-CoV RBD and S1 subunits of MERS-CoV, HCoV-HKU1, HCoV-229E, and HCoV-NL63. The latter two are circulating CoV from the Alphacoronavirus family. Our results show that SARS-CoV RBD which has 73.8–74.9% amino acid identity with SARS-CoV-2 RBD cross-binds with antibodies from COVID-19 patients, as there is a positive correlation (Pearson correlation = 0.4316) between AUC levels measured by SARS-CoV-2 RBD and SARS-CoV RBD (Fig. 1d). This is expected considering the similarity of the RBD sequence between these two strains and that antibodies elicited by SARS-CoV-infected patients can cross-neutralize SARS-CoV-2. Antigens from the circulating human CoVs, including HCoV-HKU1, HCoV-229E, and HCoV-NL63 seemed to bind antibodies from COVID-19 patients, as well as healthy controls in varying degree, suggesting prior widespread infection of these CoVs in the general population (Fig. 1e and Supplementary Fig. S2a, b).
There look to be better approaches per that paper using S1 antigen. Also it's not clear to me how their actually used cutoff translates to the sensitivity/specificity of their test. This isn't my field so I'll leave it to someone else to examine. I'd be interested in learning how to interpret that ROC given their explanation.