Jeffrey Barrett Profile picture
Nov 25, 2021 11 tweets 3 min read Read on X
Took a look at the spike mutations in B.1.1.529 this evening, and colour coded them (details below)...there is...not much green.🧵 Image
First the obviously bad stuff (red): nine mutations seen in previous VOCs. There's a lot of overlap already among VOCs (convergent evolution), but this variant has an unprecedented sampling from mutations previously seen in Alpha, Beta, Gamma and Delta separately.
In orange are three mutations that are probably meaningful biological changes for the virus, but not previously seen in VOCs. Two from VUI level lineages that likely had modest advantages over original virus, and E484A which is at a key site in the receptor binding domain.
Next eleven things seen rarely or never before (blue) that may be functional and just new to us, or may be a side-effect of whatever process led to so many mutations in this lineage (i.e. either neutral or mildly deleterious). Need more data on these.
In green is just D614G, which has been fixed in all SARS-CoV-2 since early 2020.
Finally, three shades of purple which are new (not in previous VOCs) but have some other data to suggest they may be functional. First is a deletion/substitution/insertion hotspot in the N terminal domain, that may be further remodelling the protein structure there.
Then there's a group of 4 nearby substitutions (3 in the space of 5 amino acids) that have not been seen before, but are so close together that I doubt its coincidence. They are also very close to the (previously conserved) binding site of sotrovimab, a therapeutic antibody. Image
Finally S477N and Q498R, predicted in an experimental evolution paper to substantially increase ACE2 binding together with N501Y, but only seen in the wild separately or rarely. Seeing this full combination now (along with everything else) is grim.
nature.com/articles/s4156…
There are also multiple (possibly funcitonal) mutations in genes other than spike: notably R203K and G204R in nucleocapsid, which were recently shown to be key in increasing transmissibility, and are present in all VOCs to date. science.org/doi/10.1126/sc…
So the mutation profile is bad (as @PeacockFlu and others have already pointed out). We don't yet know how they act together, or how a virus with so many changes will behave.
We need to learn more, fast. To end on a hopeful note, it's mind-blowing how quickly we've got this far. Kudos to @Tuliodna et al for getting this out, and setting the global scientific community onto experiments to answer more of these questions. Let's get to work.

• • •

Missing some Tweet in this thread? You can try to force a refresh
 

Keep Current with Jeffrey Barrett

Jeffrey Barrett Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @jcbarret

Sep 22, 2022
The goofy full name of the latest hot topic for Covid variant nerds, B.1.1.529.5.3.1.1.1.1.1.1, tells us something potentially important about the future evolution of the virus. All those dots mean it is on a deep branch of a branch of a branch... of the family tree. 🧵
This is the first time we've seen variant evolution go so far down one path away from the original 2019 virus: alpha, beta, gamma, delta, omicron were all pretty much unrelated evolutionary events from the same starting point. But all these recent sub-variants build on Omicron.
In 2 yrs of UK variant data, "age of Omicron" is the longest, and by now I'd be surprised to see something totally new (i.e. a non-Omicron descendant) take over. (NB: for a 1-year thread of how me and lots of others have been wrong about this before, see
Read 7 tweets
Feb 22, 2022
Interesting pre-print that finds 47 BA.2 re-infections after BA.1, using amazing surveillance infrastructure in 🇩🇰. Although this reminds us that getting #Omicron once doesn't confer total immunity, I think overall this is good news. 🧵 medrxiv.org/content/10.110…
First, despite very good record linkage, only 0.1% of the huge number of recent cases in DK are confirmed recent re-infections (they are focusing on re-infection within 2 months, so there will presumably be a lot more if you count any prior infection).
Second, despite enriching for Omicron-Omicron re-infections, they (unsurprisingly) find 3/4 are Delta-Omicron re-infections, which we know are part of the reason Omicron has spread so fast everywhere.
Read 5 tweets
Dec 8, 2021
In the past few days it has become clear that #Omicron can spread very quickly through highly vaccinated populations. 🧵with several pieces of evidence on this topic, and some thoughts on what next.
Previous experiments predicted Omicron-like mutational complement to substantially evade antibodies (e.g. from vax). That's why we've been nervous since it appeared.
Today there have been (at least) three postings of experimental data to confirm that Omicron is less well neutralised by antibodies from vaccine or previous infection -- clearly more than any previous VOC.
Read 10 tweets
Dec 3, 2021
First @UKHSA Tech Briefing of the #Omicron era. A lot of scene setting, as it is very early days (I'd guess there's going to be a bit more info in next week's report, and loads more the week after that). But a few early things I think worth noting: 🧵
Annotated table of defining mutations is quite handy, and runs over six pages (this lineage has a lot of mutations).
The 22 UK sequences in this report sit all over the global tree, suggesting multiple recent imports. This picture will change fast as we add more sequences.
Read 7 tweets
Dec 3, 2021
I'm not sure who these virologists are, but the ones I hang out with are definitely not working their way to this conclusion. This whole thread is based on a rather enormous misunderstanding of phylogenetics. 🧵
The thread looks at one mutation (del69/70) that's in Omicron, Alpha and some Delta in plots from outbreak.info. It asserts older sequences with del69/70 may have been "misclassified" because "we didn't know about Omicron". But we don't look at one mutation at a time!
We classify variants (Alpha, Delta etc) using the whole genome for exactly this reason: some mutations are shared by different variants. If these were Omicron, they would not get called Alpha just because of this one mutation.
Read 5 tweets
Oct 19, 2021
Proportion of AY.4.2 (now on covid19.sanger.ac.uk) has been steadily increasing in England, which is a pattern that is quite different from other AY lineages. Several of them rose when there was still Alpha to displace, but none has had a consistent advantage vs other Delta.
And it has grown all over the place between mid-July (L) and now (R). AY.4 did a similar thing, but it was not displacing other Delta, and given that it hasn't spread through the world, likely just had some epidemiological luck.
AY.4.2 hasn't yet spread much outside the UK, so could be a fluke (no biological advantage), but given that it's apparent advantage is modest, it needs to really get established somewhere to overcome stochasticity of small numbers.
Read 6 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us!

:(