The latest focal S:N501 build is now up! It includes data from 4 Jan 2021.

We have new sequences in 501Y.V1/B.1.1.7 from Denmark, Singapore, Australia, Italy, Spain, France, Portugal, Germany, Brazil, Jamaica, Luxembourg, Pakistan & the USA.

1/12

https://t.co/FTjvV7T7wL

Denmark has 43 new sequences (in orange). These indicate additional introductions, as well as further expansion of the existing large local transmission cluster we saw previously (shown in zoomed divergence view).

2/12
10 new sequences from Portugal (orange) indicate additional, separate introductions.

3/12
Singapore has 5 new sequences (yellow). These indicate at least 5 separate introductions for the total of 6 sequences, with two identical sequences likely being 1 introduction.

4/12
5 new sequences from the US, from Florida & California (older sequences crossed through).

Zooming in (divergence view) on the California cluster, the relationship between these samples is difficult to infer from phylogenies alone.

5/12
3 new sequences from Spain (orange) indicate 2 more introductions, with the 3rd new sequence linking to the first sequence (green).

6/12
2 new sequences in Germany & 1 new sequence in Australia indicate separate introductions

7/12
1 new sequences in Italy represents another separate introduction (little hard to see in this picture), and 1 new sequence from France (yellow) indicates an additional introduction.

8/12
Additionally, we have the first sequences that fall in 501Y.V1 from Brazil (1), Jamaica (1), Luxembourg (1), & Pakistan (2).

Though hard to see on the larger tree, the 2 Pakistan sequences sit apart on the phylogeny, & thus indicate separate introductions.

9/12
The S:N501 'reduced UK' build is also updated. *Please remember not to use this build to look at connections between countries!* Use it only alongside the larger, complete S:N501 build.

10/12

https://t.co/9md0yn9Qgp
Finally, the country plots have also been updated. As countries are preferentially sequencing 501Y.V1 samples at the moment, the 'hot pink' sections *do not* represent true frequencies of the variant in countries!

https://t.co/c7wlQOLRiq

11/12
We can see the current screening process in action in the Swiss chart - variants with the 69/70 deletion are being preferentially sampled. Sequences from the 439K cluster also have that deletion - they're being picked up in the search to find 501Y.V1! 🙃

12/12

More from Dr Emma Hodcroft

Lots of tweets about this today!
Let's see what we can see in the focal S:E484 build!

Phylogenetics (what I do - making 'family trees' from virus genetics) can be very informative to see how different variants are spreading, and how cases

There are two variants circulating predominantly in Brazil:
- 20B/S.484K seems to be older & more widespread. It has (among others) a mutation at position 484
- 20J/501Y.V3 is smaller & detected recently. It has mutations at 501 *and* 484.

2/10

https://t.co/Cw5u2kuATa


The variant predominantly in the UK (501Y.V1 / B.1.1.7) and the variant predominantly in South Africa (501Y.V2) also both have 501. 501Y.V2 *also* has the 484K mutation.

Why are there concerns about these mutations? You can read more at https://t.co/wVE7ubYBoy!

3/10


The view below is from an analysis focusing on sequences with a mutation at 484. It shows all the samples in the 2 variants (20B/S.484K & 20J/501Y.V3) & how they're related. More closely related = closer together (very, very roughly).

4/10


We can colour these samples by region to see where they're from. As we expect - most are in Brazil! A few are in Argentina (also red).

5/10

https://t.co/Cw5u2kuATa
Each day brings new challenges, but here's an update to the dedicated S.N501 build, using data from 6 Jan 2021 to keep you going.

There are 42 new non-UK sequences in 501Y.V1 (B.1.1.7) & 7 new non-South-African sequences in 501Y.V2.

1/14

https://t.co/kT1gFsSZn0


There are 42 new non-UK sequences in 501Y.V1 from the Netherlands, Italy, Hong Kong, Finland, Sweden, Germany, USA, Switzerland, Brazil, and the first sequence from 501Y.V1 in Oman.

https://t.co/XA8VR8HiEq

2/14


Oman has their first sequence which falls into 501Y.V1:

3/14


Finland has 12 new sequences (orange), which mostly represent separate introductions. Zooming in (divergence view), we can see 3 of the new sequences are identical (red), which may indicate the cases are connected.

4/14


Sweden has 8 new sequences (orange), which indicate separate introductions.

5/14

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