
XBB.1.9.1 – a new variant of concern?
XBB.1.9.1, a new recombinant subvariant that is suddenly cropping up across the globe, is causing some concern amongst epidemiologists.
Let’s start with the UK, where XBB.1.9.1, according to Covspectrum, is already at nearly 12% of sequences.
The UK Health and Security Agency have recently published a technical briefing giving details of variants causing concern. This is what the technical briefing has to say about XBB.1.9.1:
XBB.1.9.1 is rapidly increasing in proportion and is currently the only lineage with a significant growth advantage relative to XBB.1.5, though with small numbers identified.
As of 7 March 2023, 1,168 XBB.1.9.1 sequenced cases had been identified in England. There were 39 deaths among these cases.*
The median age of cases was 72 years old. The majority of cases were female (611), with 430 male cases (Figure 12). There have been cases in each region of England with the most cases resident in the Yorkshire and Humber (205) and East of England (195) (Figure 13). Care home residents comprised 25.3% (296 out of 1,168) of XBB.1.9.1 cases, a similar proportion to all sequenced cases.
(* our emphasis)
That is an extraordinarily high fatality rate at this point in the pandemic.
The full UK Technical Briefing 51 is republished below. The comments above come from page 23.
variant-technical-briefing-51-10-march-2023
In Singapore, where XBB.1.9.1 comprises about 12% of sequences, hospitalizations seem to be increasing:
There is also a recent increase in Singapore ICU cases:
In the Netherlands, XBB.1.9.1 is just starting to appear in the variant mix, but Dutch hospitalizations are at a high not seen since October 2022.
In France, a new Covid wave seems to be gathering pace, with XBB,1.9.1 currently as small part of the mix:
But there are some extraordinary new Covid figures from France today:
In Indonesia, XBB.1.9.1 now has a share of more than 50% of its variants
And wastewater specialist Marc Johnson predicts that XBB.1.9.1 will overtake XBB.1.5
Ryan Hisner believes XBB.1.16 could be a stronger candidate to supersede XBB.1.5 than XBB.1.9.1
This latest chart from Regeneron for the UK seem to suggest that XBB.1.9.1 has put a brake on further growth of XBB.1.5.
XBB.1.9.1 has recently been spotted in two sequences from China:
XBB.1.9.1 Growth Rate in the United States.
These two tables show the growth rate of XBB.1.9.1 over just ONE WEEK in the US.
UK: XBB.1.5 compared to XBB.1.9.1
XBB.1.9.1 outcompetes XBB.1.5 before the end of March 2023 by the look of it. (XBB.1.9.1 in green.)
We will be updating this thread with further news about XBB.1.9.1 as it breaks..