@scarpino Having read that, I have to question the tone of your summary.

I certainly hope it turns out to be a lesser variant than it appears at first, but, precautionary principle seems to be exactly what they're advocating.

1 - Yes, what you linked to shows that due to backfilling the fitness advantage may have been overestimated early on. We'll know a lot more soon.

2 - Is that your take or what you got from your link?

"Although this is a positive sign, case reports may be lagging or unreliable, so we might not be out of the woods yet."

Of course case reports lag after the holidays. Again, we'll find out.

3 - It doesn't say that at all? It says:

"Countries with prior high prevalence of XBB may have some local immunity to buffer against XBB.1.5."

And then links to a report they put out in October. That report says:

"Outside of Singapore, Bangladesh, and India, the XBB variant is still fairly uncommon."

So unless you're talking about Singapore, Bangladesh or India that seems pretty irrelevant.

Fingers crossed it's far less of a big deal than many people are predicting, but let's summarize the science correctly if we're going to post about it. It's not a "hey no big deal" report. It starts out with:

"Our model currently shows the XBB.1.5 variant is spreading quickly in the United States."

And ends with:

"In summary, we advocate for a close eye on XBB.1.5, but advise caution!"

@BE I added the second tweet to communicate that things are still quite serious. Not sure if they linked to it, but there have been studies showing sera continues to neutralize xbb.1.5

@scarpino

I'm honestly unaware of a study showing good results if you could share. These are what I'm going off of:

https://www.nature.com/articles/s41591-022-02162-x

https://www.cell.com/cell/pdf/S0092-8674(22)01531-8.pdf?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867422015318%3Fshowall%3Dtrue

@BE Figure 1 C/D look pretty good to me. Obviously XBB and BQ.1.1 are breaking through, but a lot less that w/out the bivalent booster. Early data suggests XBB.1.5 is similar https://twitter.com/yunlong_cao/status/1607915567696203776?s=20

@scarpino

Uh, no? I'm not going to lie here. I'm having a hard time figuring out what's good there.

The author of that tweet's actual paper pre-print:

https://www.biorxiv.org/content/10.1101/2023.01.03.522427v1

"SARS-CoV-2 recombinant subvariant XBB.1.5 is growing rapidly in the United States, carrying an additional Ser486Pro substitution compared to XBB.1 and outcompeting BQ.1.1 and other XBB sublineages. The underlying mechanism for such high transmissibility remains unclear. Here we show that XBB.1.5 exhibits a substantially higher hACE2-binding affinity compared to BQ.1.1 and XBB/XBB.1. Convalescent plasma samples from BA.1, BA.5, and BF.7 breakthrough infection are significantly evaded by both XBB.1 and XBB.1.5, with XBB.1.5 displaying slightly weaker immune evasion capability than XBB.1. Evusheld and Bebtelovimab could not neutralize XBB.1/XBB.1.5, while Sotrovimab remains its weak reactivity and notably, SA55 is still highly effective. The fact that XBB.1 and XBB.1.5 showed comparable antibody evasion but distinct transmissibility suggests enhanced receptor-binding affinity would indeed lead to higher growth advantages. The strong hACE2 binding of XBB.1.5 could also enable its tolerance of further immune escape mutations, which should be closely monitored."

Yunlong Richard Cao goes on to retweet Dr Ding's dire predictions of XBB 1.5.

Then links to a paper:

https://www.biorxiv.org/content/10.1101/2022.12.27.521986v1

"In vitro experiments revealed that XBB is the most profoundly resistant variant to BA.2/5 breakthrough infection sera ever and is more fusogenic than BA.2.75"

I'm sorry. There's zero positive here.

@BE I'm sure the breakthrough rate is higher and I'm not saying things look good. What I'm saying is they don't really look that much worse than they already are, which is quite bad.