Thread by @profshanecrotty

3 studies today on antibodies & Omicron.
🔵 There may be a large drop in neutralization of Omicron
🔵 Antibodies stop Omicron well in hybrid immunity (infected+vax)
🔵 Sotrovimab is active versus Omicron

Take home: Get vaccinated. Get boosted. Immune system is clever. 🧵 1/n

Live virus neutralization preliminary data from @Sigallab in South Africa found a 41x drop in vax neutralization of Omicron. That is a large drop. Seeing hybrid immunity do much better is encouraging. Average Omicron neutralization of ~1,000 was good (>vax neut of WT). 2/n

Neutralizing breadth in hybrid immunity is outstanding. And we know that 3-dose (boosted) vaccine partially recapitulates that improvement in breadth. 3/n

The hope is that, based on neutralizing data of other variants, 3-dose vaccinated neutralization of Omicron may be reasonable—MAY. *speculation* for now. 4/n

A helpful reference point is a difficult previous SARS-CoV-2 variant: Beta.
Booster immunization studies by Moderna and Pfizer showed that, while there was a 15x drop in neutralization of Beta for people vaxxed with 2-dose, Abs vs Beta were MUCH better after a booster shot. ~15x

(regular booster. not even Beta). ~15x improvement. Such that 3-dose RNA neutralization of Beta was as strong as 2-dose neutralization of 'regular' SARS2. 6/n

That's because the immune system B cells can frequently learn how to recognize a virus better and better, and make guesses about potential variants. 7/n

It is outstanding that @sigallab got these data so quickly. What many of us want to see is:
* Head-to-head comparisons against other variants, because of the broader experience with them.
* Neutralization of Omicron by serum from people with 3-doses of an RNA vaccine. 8/n

A second study also posted today, with Omicron pseudovirus neutralization data, from the Karolinska. This study had four notable findings:

a) 40x drop in Omicron neutralization by the WHO standard plasma, from COVID donors.

b) 5x drop in Omicron neutralization by people with hybrid immunity

c) 7x drop in Omicron neutralization by random blood donors. Presumably mostly vaxxed and uninfected? Unknown

d) Minimal difference in neutralization of Omicron versus Delta

Those last three observations (b, c, d) are pretty close to the best case scenario I was considering. 14/n

They must have gotten these data in about a week, which is very impressive! 15/n

https://twitter.com/BenjMurrell/status/1468341478363746310

Like everything in science, it is really valuable to get data from multiple labs, for confirmation and because not everyone does experiments exactly the same way. So it will be very valuable to see other studies in the coming days. 16/n

I do expect there to be T cell data related to Omicron in the next week or so. 17/n

Regarding memory B cells: The hybrid immunity outcomes and the 3-dose (boosted) RNA vaccine outcomes combined with the Sigal and Murrell data indicate that memory B cells have a good chance of recognizing Omicron well.(see above) But I would like to see more direct data. 18/n

Monoclonal Sotrovimab retains activity against Omicron
Good news!
A 2.7x shift, so it should still be an effective COVID therapeutic drug in high risk patients. 18/n
biorxiv.org/content/10.110…

So, again, current take home messages for Omicron immunity: Get vaccinated. Get boosted. Hybrid immunity is good.
end/n

Main figure of the Sheward / Murrell preprint. (I forgot it above)