Zach Hensel
@zachhensel.bsky.social
single-molecule microbiology lab @ ITQB NOVA in Portugal
https://zach-hensel.github.io/
https://zach-hensel.github.io/
Pinned
Zach Hensel
@zachhensel.bsky.social
· Apr 5
If you’re wondering why all the tips line up in Fig 3A, it’s because dates weren’t used in analysis inferring… dates of ancestors.
Well, one date must have been used as well as one scaling factor, but it’s not described well enough to be reproduced 🤷
Well, one date must have been used as well as one scaling factor, but it’s not described well enough to be reproduced 🤷
Here's Figure 3 from the paper.
- 3A: Conflates "spillover date" with tMRCA of 2019.58; not the same thing and also a badly wrong estimate of tMRCA for many reasons.
- 3B: Same error as 3A; SARS-CoV-2 tMRCA informed by zero lineage A sequences with 84% of these derived from B.1.
- 3A: Conflates "spillover date" with tMRCA of 2019.58; not the same thing and also a badly wrong estimate of tMRCA for many reasons.
- 3B: Same error as 3A; SARS-CoV-2 tMRCA informed by zero lineage A sequences with 84% of these derived from B.1.
December 30, 2025 at 12:46 PM
If you’re wondering why all the tips line up in Fig 3A, it’s because dates weren’t used in analysis inferring… dates of ancestors.
Well, one date must have been used as well as one scaling factor, but it’s not described well enough to be reproduced 🤷
Well, one date must have been used as well as one scaling factor, but it’s not described well enough to be reproduced 🤷
Confused about this Correction in @plosone.org @plos.org that explains why the title and abstract are wrong in a paper full of literally impossible results, yet concludes "the article’s overall results and conclusions are upheld" -- journals.plos.org/plosone/arti...
Correction: Assessing the emergence time of SARS-CoV-2 zoonotic spillover
journals.plos.org
December 30, 2025 at 9:50 AM
Confused about this Correction in @plosone.org @plos.org that explains why the title and abstract are wrong in a paper full of literally impossible results, yet concludes "the article’s overall results and conclusions are upheld" -- journals.plos.org/plosone/arti...
Reposted by Zach Hensel
JB: Hey Matt, you got a minute?
MM: Sure, Jay, whazzzup?
JB: We gotta do the Pete n' Bobby challenge!
MM: What?
The P&B challenge is up on MM's screen as this is all taking place 😂
MM: Sure, Jay, whazzzup?
JB: We gotta do the Pete n' Bobby challenge!
MM: What?
The P&B challenge is up on MM's screen as this is all taking place 😂
December 19, 2025 at 6:28 PM
JB: Hey Matt, you got a minute?
MM: Sure, Jay, whazzzup?
JB: We gotta do the Pete n' Bobby challenge!
MM: What?
The P&B challenge is up on MM's screen as this is all taking place 😂
MM: Sure, Jay, whazzzup?
JB: We gotta do the Pete n' Bobby challenge!
MM: What?
The P&B challenge is up on MM's screen as this is all taking place 😂
Marty Makary was asked this question the other week: "Where did AIDS come from?"
His answer: "It may very well have come from a lab in Africa"
How is this not a national scandal?
His answer: "It may very well have come from a lab in Africa"
How is this not a national scandal?
December 16, 2025 at 6:52 PM
Marty Makary was asked this question the other week: "Where did AIDS come from?"
His answer: "It may very well have come from a lab in Africa"
How is this not a national scandal?
His answer: "It may very well have come from a lab in Africa"
How is this not a national scandal?
Reposted by Zach Hensel
Here is a strong-worded takedown video on many lab leak conspiracy peddlers.
I worked with @profdaveexplains.bsky.social on this and it will hit the lableak believers like a meteor.
Please enjoy "scicomm unfiltered":
youtu.be/ra0WKNhQZ0U?...
I worked with @profdaveexplains.bsky.social on this and it will hit the lableak believers like a meteor.
Please enjoy "scicomm unfiltered":
youtu.be/ra0WKNhQZ0U?...
COVID Origins: Debunking the Grift, Pseudoscience, and Politics of the Lab Leak Theory
YouTube video by Professor Dave Explains
youtu.be
December 12, 2025 at 4:28 PM
Here is a strong-worded takedown video on many lab leak conspiracy peddlers.
I worked with @profdaveexplains.bsky.social on this and it will hit the lableak believers like a meteor.
Please enjoy "scicomm unfiltered":
youtu.be/ra0WKNhQZ0U?...
I worked with @profdaveexplains.bsky.social on this and it will hit the lableak believers like a meteor.
Please enjoy "scicomm unfiltered":
youtu.be/ra0WKNhQZ0U?...
Here's a story that you're not familiar with because, correctly, no one has ever reported it. The sequencing data in this study also has thousands of reads that map to SARS-CoV-2 in wildlife samples: www.frontiersin.org/journals/mic...
Are you familiar with the story of the Antarctica sequences?
If not, good for you: you didn't clutter your brain with yet another Covid-origin damp squib, where innocuous data were made to look suspicious by misrepresenting a date.
For the curious, here's the story. ▫️1/9 🧵 #CovidOrigin
If not, good for you: you didn't clutter your brain with yet another Covid-origin damp squib, where innocuous data were made to look suspicious by misrepresenting a date.
For the curious, here's the story. ▫️1/9 🧵 #CovidOrigin
December 4, 2025 at 1:05 PM
Here's a story that you're not familiar with because, correctly, no one has ever reported it. The sequencing data in this study also has thousands of reads that map to SARS-CoV-2 in wildlife samples: www.frontiersin.org/journals/mic...
Not only derived mutations, but combinations of mutations that defined specific lineages that didn't exist in 2019. It was always impossible that this contamination occurred in 2019 and it was irresponsible to speculate otherwise based on some 2nd or 3rd hand information.
The sequences however contained mutations that clearly look derived, i.e. not compatible with being from the earliest SARS-CoV-2 viruses infecting humans -- as noted at the time, among others, by @kgandersen.bsky.social, and more recently highlighted by @zachhensel.bsky.social ▫️4/9
December 4, 2025 at 11:34 AM
Not only derived mutations, but combinations of mutations that defined specific lineages that didn't exist in 2019. It was always impossible that this contamination occurred in 2019 and it was irresponsible to speculate otherwise based on some 2nd or 3rd hand information.
Reposted by Zach Hensel
Die Wissenschaftssendung „nano“ des öffentlich-rechtlichen Senders 3sat wollte Ende Juni vermeintlich neue Indizien zum Herkunft der Pandemie gefunden haben.
Eine Spurensuche zwischen Phantasie und Pandemie.
radiocorax.de/phantasie-un...
Eine Spurensuche zwischen Phantasie und Pandemie.
radiocorax.de/phantasie-un...
November 28, 2025 at 9:26 AM
Die Wissenschaftssendung „nano“ des öffentlich-rechtlichen Senders 3sat wollte Ende Juni vermeintlich neue Indizien zum Herkunft der Pandemie gefunden haben.
Eine Spurensuche zwischen Phantasie und Pandemie.
radiocorax.de/phantasie-un...
Eine Spurensuche zwischen Phantasie und Pandemie.
radiocorax.de/phantasie-un...
Reposted by Zach Hensel
TIP: Anyone who posts wild speculation as something that is “almost certainly” the case right now is ~almost certainly~ someone you should not rely on in moments where news is breaking and a story is rapidly developing.
November 26, 2025 at 9:09 PM
TIP: Anyone who posts wild speculation as something that is “almost certainly” the case right now is ~almost certainly~ someone you should not rely on in moments where news is breaking and a story is rapidly developing.
Reposted by Zach Hensel
I share this with respect for the many excellent journalists at the BBC.
And with the hope that transparency helps strengthen, not weaken, our democratic culture. /5
And with the hope that transparency helps strengthen, not weaken, our democratic culture. /5
November 25, 2025 at 9:26 AM
I share this with respect for the many excellent journalists at the BBC.
And with the hope that transparency helps strengthen, not weaken, our democratic culture. /5
And with the hope that transparency helps strengthen, not weaken, our democratic culture. /5
Top result; searching from Portugal and not USA. FYI @developers.google.com
November 20, 2025 at 2:02 PM
Top result; searching from Portugal and not USA. FYI @developers.google.com
0️⃣ Don't take advice from the guy who promoted a movie saying HIV, Ebola, and more were lab leaks, too: www.the-gallop.com/from-fauci-t...
Utterly disqualifying and a complete embarrassment.
Utterly disqualifying and a complete embarrassment.
November 14, 2025 at 5:54 PM
0️⃣ Don't take advice from the guy who promoted a movie saying HIV, Ebola, and more were lab leaks, too: www.the-gallop.com/from-fauci-t...
Utterly disqualifying and a complete embarrassment.
Utterly disqualifying and a complete embarrassment.
A ghost draws near!
November 10, 2025 at 11:05 PM
A ghost draws near!
I added a short section to this preprint describing another simple and inexplicable error that Bruttel et al. have repeated for years.
![Misinterpretation of previous work
One criteria of the
“IVGA fingerprint” described by Bruttel et al. is
“Two unique recognition sites may flank regions
meant to be further manipulated.
” I did not consider this in the analysis above, because its inclusion in the
“fingerprint”
arises from misinterpretation of work described in a previous paper. Bruttel et al. write that this work
“
used two distinct endonucleases for genome assembly, with two sites of one enzyme [BsaI] flanking a region of
interest, enabling efficient manipulations of the flanking region without having to reassemble the entire viral
backbone for each variant.
” In fact, BsaI sites used for this assembly were not retained in the final construct (Hu et al.,
2017). Furthermore, infectious clones produced in that work did have BsaI sites in the backbone and in other
fragments that would make this procedure impossible without additional mutagenesis. In general, I could not find any
precedent in the literature on similar reverse genetics constructs for introducing type IIS restriction sites. Bruttel et al.
exclusively list examples of introducing BglI sites (not type IIS). There are some examples of removing sites to enable
one-pot assembly, but the fact that RecCA shares the SARS-CoV-2 BsaI/BsmBI restriction map strongly suggests that
there is no history of this for SARS-CoV-2 (Pekar et al., 2025).](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:x43yqs76dtuxqf7yzkqrlz4v/bafkreifstpgyyowj4m745ddrx5pbraua7j6aexqhoy4y4y5u7fgbr7hmpi@jpeg)
November 5, 2025 at 2:45 PM
I added a short section to this preprint describing another simple and inexplicable error that Bruttel et al. have repeated for years.
Reposted by Zach Hensel
Two weeks ago, a paper came out, claiming that the 2019 Brucella leak in Lanzhou, China, could have been detected months before it was publicly reported.
Problem: no proof was provided to support this extraordinary claim, as we explain in a letter to the editor.
Details follow ▫️1/6🧵
Problem: no proof was provided to support this extraordinary claim, as we explain in a letter to the editor.
Details follow ▫️1/6🧵
Correspondence regarding “Geospatial analysis of open-source intelligence data to early detect laboratory-acquired infections, using the 2019 brucellosis laboratory leak in China as a case study” - In...
Infection -
link.springer.com
November 3, 2025 at 8:30 PM
Two weeks ago, a paper came out, claiming that the 2019 Brucella leak in Lanzhou, China, could have been detected months before it was publicly reported.
Problem: no proof was provided to support this extraordinary claim, as we explain in a letter to the editor.
Details follow ▫️1/6🧵
Problem: no proof was provided to support this extraordinary claim, as we explain in a letter to the editor.
Details follow ▫️1/6🧵
🧵 Co-author Tony VanDongen has responded on X, arguing that recombination can't explain what they found.
His argument: If SARS-CoV-2 acquired one of its BsaI sites from RmBANAL247, it would have acquired the two adjacent sites!
While not a good argument, it's worse argument in light of new data.
His argument: If SARS-CoV-2 acquired one of its BsaI sites from RmBANAL247, it would have acquired the two adjacent sites!
While not a good argument, it's worse argument in light of new data.
October 31, 2025 at 1:22 PM
🧵 Co-author Tony VanDongen has responded on X, arguing that recombination can't explain what they found.
His argument: If SARS-CoV-2 acquired one of its BsaI sites from RmBANAL247, it would have acquired the two adjacent sites!
While not a good argument, it's worse argument in light of new data.
His argument: If SARS-CoV-2 acquired one of its BsaI sites from RmBANAL247, it would have acquired the two adjacent sites!
While not a good argument, it's worse argument in light of new data.
First author Valentin Bruttel has responded over at X. Here's my quick take:
a) Mutation rates are irrelevant; I show there aren't any mutations at all, so this part of Bruttel et al, which is also nonsense, is irrelevant.
b–e) Four things that are irrelevant to analysis in his paper.
a) Mutation rates are irrelevant; I show there aren't any mutations at all, so this part of Bruttel et al, which is also nonsense, is irrelevant.
b–e) Four things that are irrelevant to analysis in his paper.
October 29, 2025 at 3:14 PM
First author Valentin Bruttel has responded over at X. Here's my quick take:
a) Mutation rates are irrelevant; I show there aren't any mutations at all, so this part of Bruttel et al, which is also nonsense, is irrelevant.
b–e) Four things that are irrelevant to analysis in his paper.
a) Mutation rates are irrelevant; I show there aren't any mutations at all, so this part of Bruttel et al, which is also nonsense, is irrelevant.
b–e) Four things that are irrelevant to analysis in his paper.
🧵Remember the preprint claiming SARS-CoV-2 has a "synthetic fingerprint"?
It said a restriction map was "extremely unlikely to have arisen by random evolution.”
I took its claims seriously.
The "synthetic fingerprint" hypothesis collapses. My new preprint explains why.
arxiv.org/abs/2510.23833
It said a restriction map was "extremely unlikely to have arisen by random evolution.”
I took its claims seriously.
The "synthetic fingerprint" hypothesis collapses. My new preprint explains why.
arxiv.org/abs/2510.23833
October 29, 2025 at 7:32 AM
🧵Remember the preprint claiming SARS-CoV-2 has a "synthetic fingerprint"?
It said a restriction map was "extremely unlikely to have arisen by random evolution.”
I took its claims seriously.
The "synthetic fingerprint" hypothesis collapses. My new preprint explains why.
arxiv.org/abs/2510.23833
It said a restriction map was "extremely unlikely to have arisen by random evolution.”
I took its claims seriously.
The "synthetic fingerprint" hypothesis collapses. My new preprint explains why.
arxiv.org/abs/2510.23833
Really valuable and very normal feedback from Dr. Ebright the last two months.
October 26, 2025 at 10:44 AM
Really valuable and very normal feedback from Dr. Ebright the last two months.
Response from @philippmarkolin.bsky.social www.statnews.com/2025/10/25/s...
I was in high school in Kansas when this happened!
Rumsfeld said: there are known knowns, known unknowns, and unknown unknowns. He oddly excluded unknown knowns which are important to consider for complex topics.
I was in high school in Kansas when this happened!
Rumsfeld said: there are known knowns, known unknowns, and unknown unknowns. He oddly excluded unknown knowns which are important to consider for complex topics.
October 25, 2025 at 1:16 PM
Response from @philippmarkolin.bsky.social www.statnews.com/2025/10/25/s...
I was in high school in Kansas when this happened!
Rumsfeld said: there are known knowns, known unknowns, and unknown unknowns. He oddly excluded unknown knowns which are important to consider for complex topics.
I was in high school in Kansas when this happened!
Rumsfeld said: there are known knowns, known unknowns, and unknown unknowns. He oddly excluded unknown knowns which are important to consider for complex topics.
The FBI report concluding a "lab leak" origin is out by FOIA, mostly redacted. What's not redacted is a silly conspiracy theory in place of actual evidence.
First picture is the FBI report. Second picture is the DoS cable it's likely referencing here.
First picture is the FBI report. Second picture is the DoS cable it's likely referencing here.
![Unredacted text from 2021 FBI "lab leak" investigation report reading: "A November 2020 Italian serological study claimed there was evidence of SARS-CoV-2 circulating in Italy pre-global pandemic; this was published in an obscure Italian medical journal and the research institute was the recipient of Chinese funding, per the DoS [Department of State].](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:x43yqs76dtuxqf7yzkqrlz4v/bafkreidix2c57vmx2nq4fofj43auoonphxcwnjandbkcpv52amlnwyixye@jpeg)
![Excerpt from State Department cable from 23 Nov 2020 released by FOIA. Text:
The Possible Source
4. (U) In an interview with Italy's Corriere della Sera on November 17, one of the principal authors of the study tried to defend his results and said the group had tried to publish in Nature, the New England Journal of Medicine, or another more well-known journal but it was not accepted. He admitted to the interviewer that he had been in contact with both the WHO and Chinese authorities about the results. The story generated considerable enthusiasm among China-based social media users. PRC state media also seized on the story. Notably, the Chinese Communist Party's People's Daily first covered the study on November 16, and T-House (part of China Global Television Network) interviewed one of the study's authors on November 18. And on November 23, PRC media company Xinhua published an article titled "Why COVID-19's origin story is still a mystery" that relied heavily on the Italian study's findings.
5. (SBU) NCI is a governmental institution overseen by the Lombardy regional government and funded by both the region and the ministries for health and research. NCI's website contains a July 2020 research cooperation agreement (attached) with the Italian Chinese Institute (ICI; Istituto Italo Cinese), an organization with no publicly known funding sources and whose principal work is establishing exchange agreements between Italian and Chinese entities. The agreement specifies further research cooperation with Chinese doctors, including the eventual presence of Chinese doctors and researchers at NCI. The NCI-ICI agreement outlines future agreements with the Chinese Ministry of Health to advance cooperation with Chinese researchers, institutions, and hospitals. ICI's scientific committee includes a researcher from NCI, and the ICI committee traveled to China in 2018 to explore further possibilities for cooperation.
Italian Funding Issues [truncated...]](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:x43yqs76dtuxqf7yzkqrlz4v/bafkreigbdkv6qnfjswkxd7h6nxkxua4mhukavibe4rpoo7lro3xetevdou@jpeg)
October 22, 2025 at 9:45 AM
The FBI report concluding a "lab leak" origin is out by FOIA, mostly redacted. What's not redacted is a silly conspiracy theory in place of actual evidence.
First picture is the FBI report. Second picture is the DoS cable it's likely referencing here.
First picture is the FBI report. Second picture is the DoS cable it's likely referencing here.
Reposted by Zach Hensel
AF-CALVADOS: AlphaFold-guided simulations of multi-domain proteins at the proteome level https://www.biorxiv.org/content/10.1101/2025.10.19.683306v1
October 20, 2025 at 1:47 AM
AF-CALVADOS: AlphaFold-guided simulations of multi-domain proteins at the proteome level https://www.biorxiv.org/content/10.1101/2025.10.19.683306v1
CBS News finally has a story on it... I fact checked a few state capitols in states with Republican governors. Four out of the first four alphabetically was enough to know you'd blow by any definition of "several".
October 19, 2025 at 9:19 AM
CBS News finally has a story on it... I fact checked a few state capitols in states with Republican governors. Four out of the first four alphabetically was enough to know you'd blow by any definition of "several".