Thread by @vipintukur

Why did triple vaxxed #Israel recently purchase enough @Novavax vaccine shots to jab their entire population?

Because this is the one vaccine that holds promise to work ag diff future variants!

But, this is a mystery why one of the best Covid vax is still sitting on bench!
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Just sharing few key points of a great analysis of this vaccine by @michaelzlin

A recent study by Novavax suggests it may be able to provide broader protection across variants than other vaccines so far. That is a great news, if true! 2/

medrxiv.org/content/10.110…

Besides a potentially broader antibody response, Novavax has the advantage of being stable in the refrigerator, so should be easier to distribute as well
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While Abs recognizing #Omicron are lower than other variants, the difference is not that big. Anti-Omicron Abs seem higher at both times than other vaccines. 4/

After a 3rd shot of Novavax. There the levels of anti-Omicron nAbs are 214; that's even higher than the 120 for anti-ancestral nAbs that gave 95% VE. So you might predict 3 doses of Novavax will give >95% VE against Omicron. 5/

Omicron evading antibodies produced by most vaccines is no surprise, because Omicron is mutated in most of the antibody recognition sites on spike. We knew it would be highly immunoevasive.

Yet Novavax appears different. How can that be? 6/

We know there are regions in spike that can be targeted by Abs & that are conserved across all strains.

It's been an open question whether we can make a vaccine that can elicit a significant response to that epitope. Perhaps that is what Novavax is doing. 7/

And why might it be doing that?

It could be that Novavax's format as a protein nanoparticle or the adjuvant used promotes spike uptake and antigen presentation by APCs (DCs or macrophages) differently than when spike is expressed in muscle cells by the other vaccines. 8/

Perhaps this different route of antigen uptake leads to a different propensity for conserved sequences to be presented, and that leads to a set of antibodies that is more broadly reactive across strains. 9/

So just a hypothesis for now, but it's important to figure this out. If it is indeed the case that this format presents a broader array of epitopes, then that would suggest Novavax may be more robust to unforeseen variants, in which case it should perhaps be prioritized. 10/

This is the full 🧵 by @michaelzlin 👇

https://twitter.com/michaelzlin/status/1488957682874679298