NEW: time for a proper thread on B.1.617.2, the subtype of the Indian variant that has been moved to "variant of concern" today by Public Health England.

First, it’s clear case numbers from this lineage are growing faster than other imported variants have done in the UK.
Here’s the same thing on a logit scale (HT @trvrb), which makes it easier to compare growth rates.

As we can see, B.1.617.2 is on a fairly steady upward trajectory, which other variants failed to achieve.
So we know its trajectory looks different to the other imported variants, but that doesn’t tell us enough. We need a better benchmark: how does its growth compare to B.1.1.7 at the same stage of its emergence?

Remarkably similar, it turns out:
In terms of its share of all sequenced UK cases, B.1.617.2 is following ~exactly the same path as B.1.1.7 did last year.

But there’s a caveat here, and it’s a double-edged caveat.
Because overall UK case numbers are much lower today than they were last November, the same % of cases is a smaller number.

If we map those %s onto total UK cases, we see there are much fewer new B.1.617. 2 infections today than there were with B.1.1.7 at the same point.
And indeed, if we plot the same thing on a log scale, there are also signs B.1.617.2 may be following a slightly shallower ascent than B.1.1.7, too.
But the flip-side of this is, B.1.1.7 was growing when there was more social mixing. Conditions were favourable to transmission.

Numbers of B.1.617.2 are rising at a time of less mixing. This has led some to worry that it could be more transmissible (but we don’t yet know this).
So how should we think about all of this?

First, there’s the data itself: it’s critical that we know how many of the B.1.617.2 cases are second-generation cases from returning travellers, and how many are genuine community spread.

Today PHE said almost half are travel-related.
All returning travellers have their tests sequenced, so we know this inflates numbers for B.1.617.2.

If national trend is downward, and you have a glut of travellers returning from India, the imported cases (and their secondary cases) alone could artificially imply rapid growth.
Hopefully we keep getting breakdowns of how many were linked to returning travellers and how many were not. In the absence of that, it’s a case of wait and see.

It was several weeks after this point that B.1.1.7 really took off. That may happen with B.1.617.2, or it may not.
So that’s the issue with the data itself, but more important is what all of this means in the context of the vaccines.

And here, there are lots of reasons to be optimistic:
First, B.1.617.2 does not have the E484Q mutation, which has been linked to immune escape.

Among its mutations is L452R, which @GuptaR_lab has found to be less immune-evasive than the mutations found in e.g the Brazilian and South African variants
And second, the data we do have on people being infected with B.1.617.2 after receiving the vaccine is — despite claims to the contrary — very reassuring.

Even among the most vulnerable populations, infections are not turning into severe illness or death
This is strongly supportive of the last point about mutations & immune escape:

If (and it remains an if) B.1.617.2 is found to be more transmissible than other variants, it doesn’t look like vaccines will struggle to protect infected people from getting seriously ill.
As @mugecevik told @AnnaSophieGross in our story, "Right now the most important thing is that the vaccines are working against this variant".

And it really is as simple as that until we learn more.

As I’ve been saying, keep *watching*, but don’t keep *worrying*.
Here’s our full story:…

And here’s @PHE_uk’s report today…
Final comments:

I’ve deliberately included the "numbers are rising!" charts alongside the caveats about why that is not necessarily reason to worry. I think it’s important to show the raw data, even if there are many reasons to take it with a pinch of salt.
I also want people to realise 2 things can both be true: numbers rising, and the situation not necessarily being scary.

It’s not either or. If someone shows you a scary chart of rising numbers, ask whether it really is scary given what else we know (and hey, perhaps it will be).
I’ll continue to share as much information as I have on B.1.617.2 as the picture becomes clearer.

As ever, feel free to get in touch with questions, comments etc.

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More from @jburnmurdoch

5 May
Quick mini-thread on the Seychelles:

There has been a surge in cases in the last few days, but as we’ve often seen lately, when you dig beneath the surface this is consistent with the vaccines working as advertised.
• More than half of people in the Seychelles are fully vaccinated. The rest are mostly unvaccinated (very few with just one dose)
• But only one-third of active cases there have been vaccinated
• So that means the unvaccinated are roughly twice as likely as the vaccinated to have been infected, which is completely in-line with the 50% efficacy reported for Sinovac (the main vaccine in use in the Seychelles)
Read 6 tweets
4 May
Brief thread on vaccines vs variants (vaccines are winning 💉💪):

[Some] people keep pointing to rising cases in places like Chile and Canada as evidence that the vaccines aren’t working.

That’s completely contradicted by the data coming out of those countries
First, an update from Chile, where cases, ICU admissions and deaths are now all falling among the elderly, who were prioritised for vaccination (while still rising or stable among younger, less-vaccinated groups).
Chile is one of the clearest examples worldwide:
• Rates were on exactly the same path among young & old before vaccines
• They then diverged, with the elderly (💉) faring better
• If deaths among 70+ had stayed on the same path as the 0-59s, 1,500 more people would have died
Read 15 tweets
1 May
Brief interlude from Covid content today

I recently decided work wasn't busy enough (lol) and set out to build a garden table from scratch. Easily one of the most rewarding things I've done.

Here's a step-by-step, starting with ~60m of wood arriving, too big to bring indoors 😅
So the race was on to cut the wood small enough to bring inside before any rain.

Lots of sawing, some with a circular saw until neighbours complained (not unreasonably), and then hand-saw for the rest.

Super useful tool here for calculating cuts:…
With everything cut to size, next step was sanding down all edges to make sure nobody would sit on a splinter.

Unfortunately the electric sander also proved unpopular with neighbours, so I hand-sanded 40-odd planks 😅

Then it was a case of waiting for optimal painting weather.
Read 12 tweets
21 Apr
NEW thread: here’s the latest data on how vaccines are fighting Covid.

My India tweets earlier were grim, but these are more optimistic

Vaccines are working in the UK ✅, working in the US ✅, and contrary to alarmist reports, they’re working in Chile ✅…
First, some more detail on the UK.

Cases, hospital admissions and deaths have fallen steeply among all groups (the 'restrictions effect'), but have fallen furthest and fastest among the older, most-vaccinated groups (vaccine effect).
(For anyone wondering why the UK deaths lines are getting bumpy, that’s a good thing:

The numbers are now so small — 20 Covid deaths per day — that random variation starts making things look noisy)
Read 17 tweets
21 Apr
NEW: a deep-dive into the situation in India, where a devastating second wave is overwhelming hospitals and crematoriums, eclipsing global records as it goes…

250,000 new cases every day, and test positivity is soaring suggesting many are still missed
To put this into a global context, much has been made of the resurgences in Europe and North America over recent weeks, but India’s wave has accelerated straight past all of them.

The situation there really is beyond what we’re seeing anywhere else worldwide.
In many parts of the country including the capital Delhi, cases are doubling every five days. Compared to the steady rise seen in the first wave last year, the current climbs are almost vertical.
Read 10 tweets
16 Apr
NEW: the variant thought to be responsible for fuelling India’s grim second wave (B.1.617) has been found in the UK, and numbers are rising relatively quickly in Britain.

Story from @AnnaSophieGross & @JasmineCC_95…

Quick thread on caveats:
1) Numbers are very small (<100 sequenced cases so far), which means random variation and patterns in testing can play an outsized role in driving the overall trajectory.

We can see this with the Brazilian and South African variants, whose trends are anything but established.
2) We have vaccines now, so key question is not just "is B.1.617 spreading fast?", it’s also "do the vaccines work as well on B.1.617 as they do on B.1.1.7?"

We don’t know the answer to that yet, but with vaccinations rolling out in India, I suspect we’ll start to find out soon.
Read 7 tweets

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