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 link🙂


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.


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 CoVariants.org!

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).

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).


If we look just at 20B/S.484K (top cluster), we can see there are clusters of sequences in the UK, Canada & the USA, and exports to Norway, Malaysia, & Australia.


Importantly, the clusters in the USA & Canada are identical (though each country also has an additional imports), so they may be from a group of travellers returning, rather than local transmission (left pic). They also date from Nov - so not recent (right pic).

We can see 8 UK sequences in the 20B/S.484K cluster. There are 2 clusters, but neither are identical. They could be from a common exposure (same part of Brazil, same travel group), or possibly be local transmission. These samples are from Nov & Dec.


If we look at 20J/501Y.V3, we can see that sequences only are found in Brazil and Japan (known travel to Brazil), but no other countries.


Hopefully, this thread helps distinguish what the '2 variants' are that are circulating in Brazil, and from which there have been samples detected in the UK.

And, I hope it shows how phylogenetics can help us 'tell viruses apart' & follow them as they move & change!

To add: why are scientists concerned about these variants circulating primarily in Brazil?

@BillHanage write a fantastic thread here:


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More from @firefoxx66

14 Jan
There's been a lot of news today about 'new variants in Brazil' & 'S:E484' and 'Ohio variants'. A short thread discussing what we know about each.


#SARSCoV2 #Ohio #BrazilVariant #Brazil #COVID19
There are two variants circulating in Brazil: 20J/501Y.V3, recently detected in Japan & prevalent in Manaus. And temporarily-labelled '20B/S.484K', a larger clade circulating more widely in Brazil.

They both carry the spike mutation 484K, though this arise separately.

S:E484K is also found in 501Y.V2 (primarily circulating in South Africa).

Why are we particularly concerned about S:E484K? You can read more at CoVariants.org, as discussed in a tweet from earlier this week:


Read 14 tweets
14 Jan
The focal S:N501 build is now updated with data from 13 Jan!

There are a total of 247 non-UK & non-South African sequences in 501Y.V1 (B.1.1.7 #b117) & 501Y.V2.

I'll do an additional thread later on, covering S:E484 & the 'Ohio variants'.


There are 244 new sequences in 501Y.V1 (B.1.1.7) from Australia, Belgium, Denmark, Germany, India, Israel, Italy, Netherlands, New Zealand, Norway, Portugal, Singapore, Spain & USA, as well sequences as from Ecuador and Greece for the first time.

Greece has 3 new sequences in 501Y.V1 for the first time. They indicate 2 separate introductions.

Ecuador has 2 sequences for the first time. They also indicate 2 separate introductions.

Read 19 tweets
12 Jan
Happy Tuesday! The latest focal S:N501 build is now updated with sequences from 11 Jan.
There are 101 new sequences in the 501Y.V1 (B.1.1.7 #b117) & 501Y.V2 variants.

Additionally, I'll include some updates on S:E484K in this thread.


There are 97 new non-UK sequences in 501Y.V1, including the first sequences in the cluster from Slovakia, Mexico, & Belgium, plus additional sequences from the Netherlands, Denmark, Australia, Spain, Ireland, & Sweden.

Slovakia has 10 sequences that fall in 501Y.V1 for the first time. These are closely linked, & likely indicate a single introduction and ongoing transmission (remember: vertical distance is not meaningful on the same branch - position of the 2 English samples is arbitrary).

Read 23 tweets
9 Jan
To add to the excitement of your Saturday evening, the focal S:N501 build is now updated with data from 8th Jan, including 48 new seqs in 501Y.V1 (B.1.1.7 #b117) & 501Y.V2.


There are 46 new non-UK sequences in 501Y.V1, from the Netherlands, Italy, Israel, Ireland, Norway, Sweden, the USA, and Luxembourg.
And 2 new non-South African sequences in 501Y.V2, from Australia for the first time.

In 501Y.V1:

Ireland has 4 new sequences (orange). 2 sit separately but are identical, indicating an additional introduction. 2 link to a previous sequence (green), 1 mutation away each. This could indicate location transmission, unsampled diversity, or a common exposure.

Read 12 tweets
9 Jan
I'm getting some questions about this, so here you go: We do not have sequence evidence of a new, more transmissible "US variant" - it seems to be a misinterpretation.

Still, more sequencing in the US (& globally) will help us better track existing & emerging #SARSCoV2 variants!
Importantly: you can have spikes & rises in #SARSCoV2 infections without needing a new variant. We can see this clearly in Europe in autumn: we have a good idea of the variants circulating & no new (or old) variant is responsible. It was likely weather-related.
Similarly, season & holiday related changes in travel & behaviour, changing restrictions/mandates, school & university terms, & 'restriction fatigue' - just to name a few - can play a role in #SARSCoV2 case numbers. We can't & shouldn't blame every rise on a new variant.
Read 4 tweets
8 Jan
A brief update to the focal S:N501 builds to start your Friday off right! This one includes data from 7 Jan 21.

We have about 20 new sequences each in 501Y.V1 (B.1.1.7 #b117) & 501Y.V2.

Let's take a look at the new sequences, starting with 501Y.V1


There are 22 new non-UK sequences in 501Y.V1, including for the first time from Luxembourg (3), & additional seqs from Singapore (1), Australia (4), France (12), & Switzerland (2).

First, Luxembourg has 3 sequences in 501Y.V1 for the first time. Each represents a separate introduction.

Read 14 tweets

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