In that April slack conversation, the lead author expressed strong, persistent concern about a lab cultured virus that had adapted and become pandemic-ready through that process. Lab culturing = lab manipulation.
Authors have taken their names off papers for much less.
Also, in the accompanying press release from Scripps, Kristian Andersen says:
“These two features of the virus, the mutations in the RBD portion of the spike protein and its distinct backbone, rules out laboratory manipulation as a potential origin for SARS-CoV-2.”
The lead author of Proximal Origin wrote this in slack on April 17, a month after the letter had been published in Nature Medicine:
"Okay, so about the current news. Is there any reason to believe that they might be onto something, or is it all smoke and mirrors? Eddie Holmes - any insights on the China side? The main things from my perspective:
1. Bioweapon and engineered totally off the table
2. If there is no engineering and no culturing, then it means that somebody magically found a pre-formed pandemic virus, put it in the lab, and then infected themselves. The prior on that vs somebody coming into contact with an animal source infected with the virus is as close to zero as you can get. Humans come into contact all the time with SARS-like CoVs, but the likelihood of somebody finding exactly that pandemic virus and infecting themselves is very very low (make no mistake - if they did find that pandemic virus. then they would get infected if they grew it in the lab - but the likelihood of them finding it in the first place is exceedingly small (or so one would hope - otherwise, good luck World avoiding future pandemic).
3. But here's the issue - I'm still not fully convinced that no culture was involved. If culture was involved, then the prior completely changes - because this could have happened with any random SARS-llke CoV of which there are very many. So are we absolutely certain that no culture could have been involved? What concerns me here are some of the comments by Shi in the SciAm article ("I had to check the lab" etc) and the fact that the furin site 1s being messed with in vitro. Yes, it loses it but that could be context dependent. Finally, the paper that was shared with us showing a very similar phenomenon (exactly 12bp insertion) in other CoVs has me concerned...
I really really want to go out there guns swinging saying "don't be such an idiot believing these dumb theories - the president is deflecting from the real problems" but I'm warned that we can't fully disprove culture {our argument was mostly based on the presence of the O-linked glycans - but they could likely play a different role... We also can't fully rule out engineering (for basic research) - yes, no obvious signs of engineering anywhere, but that furin site could still have been inserted via gibson assembly (and clearly creating the reverse genetic system isn't hard - the Germans managed to do exactly that for SARS-CoV-2 in less than a month)."
And:
"Shi didn't do any GOF work that I'm aware of - but GOF work isn't the concern here. She did A LOT of work that involved isolating and culturing SARS-like viruses from bats (in BSL-2) and that's my main concerning scenario (we cite several of those in the paper - if you have a look at those original publications, it's definitely concerning work, no question about it - and is the main reason I have been so concerned about the 'culture' scenario)."
I don't think much more needs to be said. The above messages are self-explanatory.
Authors have taken their names off papers for much less.