We already knew by summer there were cases going back to October 19 in Italy, from saved sewage samples

Recently (3 days ago)

https://www.sciencedaily.com/releases/2021/03/210318185328.h...

Note that when the WHO team asked for similar wastewater samples from China, they were told the samples had been discarded:

> They had sought wastewater samples from central China to check if the virus could be detected in sewage from late 2019, but were told those had been discarded, per standard policy, after a month, said Dr. Koopmans.

https://www.wsj.com/articles/china-refuses-to-give-who-raw-d...

So while it's very likely that SARS-CoV-2 was circulating in Italy back in October, it's entirely possible (and likely, I believe) that it was circulating yet earlier in Wuhan; but the evidence to confirm or refute was destroyed.

And I'm replying to myself to note that the Italian study has also received an expression of concern. So "very likely" may be an overstatement, and if anything that further reinforces my point (that so far, there's no reason to believe SARS-CoV-2 was spreading outside Wuhan before it spread inside).

https://retractionwatch.com/2021/03/24/paper-claiming-presen...