Inspired by recent commentary, a thread on species barriers Nature forgot to put in place. We'll start with HIV pubmed.ncbi.nlm.nih.gov/16728595/ Next, the endemic human coronavirus pubmed.ncbi.nlm.nih.gov/29551135/

As I said yesterday, the letter by @jbloom_lab in @ScienceMagazine makes a reasonable case to avoid dismissing the possibility that #SARSCoV2 spilled over from a lab out of hand. However, as @K_G_Andersen points out, the common versions of the lab leak hypothesis suffer from being non-falsifiable, since even if evidence never emerges, adherents can (and many will/do) argue all it proves is a cover-up. So I think it would be helpful for authors of the letter and others to lay out specifically what evidence would point to a lab origin. To date there

Is broad tissue tropism of SARS-CoV-2 an unusual feature of CoVs, or is prolonged fecal shedding, for example, actually common? Mostly no one looks because no one cares, but there are hints deep in the literature. tandfonline.com/doi/full/10.10… virologyj.biomedcentral.com/articles/10.11…

There's a lot of prediction and uncertainty on the future of #SARSCoV2 in the human population. I'll do a little thread explaining why I *think* it will end up similar to the 4 "common-cold" endemic CoVs, but the time-scale on which this happens is up to us. There are currently 4 endemic human CoVs: OC43, 229E, NL63, HKU1. OC43 and HKU1 are sort of closely related, same for 229E and NL63. Overall, pretty divergent though. More different than SARS1 and SARS2, for example. They all came from animals, and they all cause mostly

Credible case reports of #SARSCoV2 reinfections have started to emerge, in contrast to earlier reports that were certainly just persistent PCR+s. It's important to document these and studying such cases in large numbers will inform our understanding of SARS2 immunity. However it does not mean that recovering from #COVID19 confers no protection. With any infection or vaccine, some subset of individuals are not going to develop lasting immunity. For example, the best vaccine we have, the measles vaccine is ~95% effective. That's great! Yet, if we

I want to spend a bit of time clearly laying out where #SARSCoV2 probably comes from, and how it could have ended up in Wuhan. Though it can't be ruled out there is currently no, zero evidence for a lab escape scenario while there is ample precedent for zoonotic spillover. Human exposure to animal viruses occurs every day worldwide, probably multiple times, due to our intense (and unwise for many reasons interactions with wildlife both directly and via agriculture. There are many examples of this resulting in zoonotic infection