[jsnell]

So, when the news broke a week ago, I was wearing my skeptic hat just like for the handful of previous announcements about "new strains". And some initial reading suggested that there was nothing to worry about. But the one data point that was so eye-popping that I thought it had to be a misprint was that 60% of the cases in London were for the new variant. It wasn't a misprint, and it wasn't isolated to London.

That is the single strongest set of data here. In the areas where both the new variant and the older ones can be distinguished (via sequencing or via the fortuitous FN from the commonly used PCR test), the new one is spreading substantially faster. This measurement is not sensitive to confounding factors such as environmental or behavioral changes, because those would affect all variants equally.

The thing that the TWIV guys seem to love repeating is that this is just a founder effect. I just don't understand where they're getting that idea from. Yes, that's almost certainly been the explanation in the earlier cases we had where one variant become predominant. But that happened in low prevalence environments. It's basically inevitable that if there are few cases, one variant or the other will become predominant just by random chance. That was not the case in the UK. In mid-October, when this variant was still basically non-existent, they were at 15k confirmed cases / day. This variant is not a founder, it was a very successful invader.

The other evidence is weaker, because it's less direct and the data is noisier. (Increased viral loads, many of the changes happening in parts of the genome that were already expected to be of biological interest, correlation studies showing that areas where the new variant is predominant have higher growth rates when controlling for other factors). That data would not be conclusive by itself. But all of it is directionally consistent with the main data point of concern, and strengthens the case.

[bjornsing]

Agree 100%. I can’t see any alternative hypothesis that explains the UK sequencing data. Here’s a good graph from a seemingly reliable source: https://twitter.com/mugecevik/status/1341094871822680067?s=2...

What could explain that data other than increased transmissibility...?