Thread by @chrischirp

THREAD:
Update on B.1.617 ("India") variant in England using latest data from the Sanger institute.

This data *excludes* sequenced cases from travellers & surge testing so "should be an approximately random sample of positive tests in the community"

TLDR: warning signs! 1/10

Data is available up to week ending 17th April.

Firstly raw counts (excluding B.1.1.7 ("Kent") which is dominant) shows rapid growth of B.1.617 ("India") over last 4 weeks.

S Africa (B.1.351) and B.1.525 variants are not growing in absolute numbers. 2/10

Looking at each variant as a proportion of all sequenced cases the rapid rise of B.1.617 ("India") is crystal clear. Remember this data *excludes* traveller and surge test data.

In week to 17 April it was almost 4% of all sequenced cases! 3/10

Where is it spreading? Sanger lets you download data by local authority - I aggregated into region and combined together B.1.617 & its sub-lineages (B.1.617.1, B.1.617.2 and B.1.617.3).

It's mainly in the South & East of England. In London it was 11% of cases w/e 17 April! 4/10

Looking just at London, you can see how the dominance of B.1.1.7 ("Kent") has reduced over last few weeks. 5/10

YES, overall London numbers have dropped A LOT since Feb & there is no indication (yet) that they are rising.

BUT we've seen rising variants masked by overall case drop / plateau before all over the world (esp spread of B.1.1.7 ("Kent")) ...

https://twitter.com/trvrb/status/1389248460017209348?s=20

6/10

... and that this has caused complacency as everything looks fine, until, one day, it's not as new variants gain dominance.

Now - best case is that we will vaccinate people fast enough & vax effective enough to prevent B.1.617 gaining dominance in London (or elsewhere) 7/10

a worse case is that B.1.617 dominates in London and then elsewhere like B.1.1.7 did before it and causes a new, limited, surge in cases until vaccination (and new local restrictions?!) can suppress 8/10

worst case is that vaccines less effective against B.1.617 and we need booster vaccines. I stress that this is *unlikely* - we need more evidence urgently but so far, looks as if our vaccines should work against it.

BUT - should we wait around to take the risk? 9/10

I think this data is saying "Take B.1.617 very seriously and surge test, contact trace, support isolation of cases & contacts, ring vaccinate - NOW".

Then we can head off any potential trouble and have the summer we all want. 10/10

PS sanger website here:
covid19.sanger.ac.uk/about

PPS we should also keep doing all we can to help India and its neighbours cope with their ongoing horrendous surges. The situation out there is not getting any better even if it's dropped off the headlines. ditto S America