Thread by @Mike_Honey_

Hong Kong is the first country to experience a wave driven by the new NB.1.8.1 variant.

From the Hong Kong surveillance report, wastewater is the most consistent indicator. That indicator is still trending upwards, to the highest level since mid-2023.
#COVID19 #HongKong
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Analysis of the impact of the new NB.1.8.1 variant in Hong Kong might be informative for those awaiting that variant in other countries.

Here's my recent thread on that topic:

🧵skywriter.blue/pages/mikehone…

Here’s the current variant picture for Hong Kong, showing the rapid “clean sweep” by the XDV.* variants, led by NB.1.8.1. In the JN.1 era (since late 2023) it has been very rare to see this, anywhere.
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The data volumes are not high, which is a challenge when analysing most places these days. But from the 40 samples collected during April, XDV.*and NB.1.8.1 are at 88% – 100% frequency, which seems definite enough.
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Considering the vaccinations available, there is of course a slow drift away from JN.1 as time goes on (it appeared in mid-2023), so there would be some loss of effectiveness. But I am hopeful it is marginal.
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Of the Spike mutation differences vs JN.1, F456L and Q493E have been in almost everything circulating in for over a year, so there would be a lot of natural immunity to those. KP.2 is a bit closer to NB.1.8.1, for jurisdictions where that vaccine is available.
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Optimistically, convergent evolution has presented the Hong Kong population with a novel combination, but a lot of that novelty has already been saturated into the population elsewhere eg in Australia.
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But not all of the novelty has been seen before, as by definition NB.1.8.1. is a new combination of mutations.
So realistically there still seems to be a fair chance that places like Australia will also experience a really big wave.
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Australia also has seasonality working against us, and the experts predict large waves of Influenza and RSV in our winter this year (see up this thread). Pulverised healthcare capacity has a snowball effect.

🧵bsky.app/profile/mikeho…

The last time the wastewater indicator was this high - in mid-2023 - Hong Kong was on the down-slope of the XBB.1.9.* "Hyperion" wave.
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The intervening significant waves were BA.2.86.* (mainly JN.1) in early 2024, and then FLiRT in mid-2024, with a long lull since.

Note that the XDV.* variant (ancestors of NB.1.8.1) have been significant for over a year, so I assume they are fairly saturated in Hong Kong .
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Hong Kong COVID-19 and Flu surveillance reports:


🧵chp.gov.hk/en/resources/2…

Interactive genomic sequencing dataviz, code, acknowledgements and more info here:

🧵 endsgithub.com/Mike-Honey/cov…