Comment by c6401

Given it was in the US at least in December 2019 if not earlier according to the NIH retrospective serology study it doesn't seem to be completely impossible. https://www.nih.gov/news-events/news-releases/nih-study-offe... Also similar Italian serology study by National Cancer Institute showed that sars-cov-2 was circulating in Italy as early as September 2019. https://www.reuters.com/article/us-health-coronavirus-italy-...