UK variant comparison

Self-updating graphs showing current situation

These graphs should auto-update every day or two, according to when there is new sequence data from COG-UK. You may need to hit shift-reload or some such to defeat your browser's cache.

These graphs compare one or more variants with another "baseline" variant. A y-co-ordinate of 0 corresponds to equal number of new cases per day of a variant compared to the baseline variant. The purpose of presenting it this way, with a particular chosen baseline variant, as opposed to several variants on an equal footing, is that it means we expect to get straight lines to some reasonable approximation.

Note that the growth estimates here rely on sequenced cases, of which there are currently about 1,000 per day, being representative of infections. This assumption may or may not hold, though it appears to work well in many cases. We often see a good linear fit over an extended period (say, several weeks) which arguably constitutes evidence in its favour, because many distortions you may think of, such as preferential sequencing of a particular variant for a limited time period, or different growth rates in different subpopulations, would often have the effect of knocking the relationship off being linear.

Program used for analysis: uk_var_comp.py.

Update 2022-08-02: adding a comparison of the BA.5* family with BA.2.75 (nicknamed "Centaurus"), because there is some concern that this variant may be a threat in some places in the world (and at the moment there don't appear to be any other variant threats on the horizon in the UK to be watching). However, BA.2.75 is not making any serious impact on cases in the UK now, nor does it seem likely to for the foreseeable. The top of the confidence interval for growth gives it a 4.1%/day advantage over the current mixture of BA.5 variants, but even at this rate it would take 5 months (9 doublings at log(2)/.041 days per doubling) to reach parity with BA.5*. Bearing in mind that that is only relative growth, and BA.5* is declining at the moment, it looks like there is some safety margin for not worrying about BA.2.75 in the UK, even if the estimates are a bit off.

As of 2022-07-11 in the UK, the overall view is that BA.5 and its subvariants, collectively written as BA.5*, are dominating, pulling clear of BA.4*, which in turn have prevailed over BA.2*. The strongest representative of BA.2* here is BA.2.12.1 (which has been strong in the US) and these three variant groups are shown in the following graph.

BA.5 has evolved some subvariants which are showing a small but significant growth advantage over vanilla BA.5. The strongest subvariants, together with BA.4, are shown in the following graph, BE.1 being an alias for BA.5.3.1.1 (daily blobs removed for clarity). These extra growth advantages (of up to 3%) over BA.5 could be a nuisance, especially if they represent immune escape rather than transmissibility, but to some extent this is already priced in to BA.5*'s growth and there appear currently to be no other variants imminently threatening to take over from BA.5* in the UK, so when the current summer wave subsides it seems likely we will have at least a couple of months of respite from Covid-19 waves. Further ahead than that is hard to predict because it relies on knowing how future variants evolve and behave.

Graphs below featuring extinct or disappearing lineages are no longer updated

(Note the y-scales below use natural logs.)