Public Health England has presented the first real-world data on vaccine efficacy against B.1.617.2, the variant first found in India.

Efficacy against symptomatic B.1.617.2 was 81% after two doses, much higher than many have feared.

I would ask people to read what follows carefully. Vaccine efficacy is a nuanced topic and the numbers here need to be interpreted in their proper context.
The data, which the FT has seen, suggest first dose offers around 35% less protection against symptomatic infection with B.1.617.2 compared to B.1.1.7, but after two doses the relative drop is only 7%.

The figures are based on pooled data from the Pfizer and AstraZeneca vaccines
Those relative reductions are FT calculations based on data showing that after one dose, protection against symptomatic infection with B.1.1.7 is 51%, falling to 33% for B.1.617.2.

And after two doses it's 87% for B.1.1.7 and 81% for B.1.617.2, a very high level of protection.
Those first dose figures of 51% and 33% may sound low, but need interpreting in their proper context:

First dose efficacy was previously estimated at between 55% and 70%, with a lot of this based on the 'pre-variant era', as it were…
Relative to that, 51% for B.1.1.7 is a small dip (if any) and one we’ve been living with. The life-saving vaccine effect we’ve seen in the UK recently is based on that level.

33% for B.1.617.2 means a modest 35% relative reduction. Not tiny, not huge, and better than for B.1.351
After two doses, the range of protection we’ve been living with is 85-90%.

The new data showing 87% for B.1.1.7 implies ~zero drop-off.

81% for B.1.617.2 is a very small dip and the confidence intervals overlap with the 85-90% range, so it’s possible there is no drop-off at all
The data suggest less vaccine escape than with B.1.351, the variant first identified in South Africa. An earlier study from Qatar found a first dose offered only 17% protection against a confirmed case of B.1.351, rising to 75% after two doses…
No PHE data yet on protection against severe disease, but it will be higher.

Two doses will give very strong protection against hospitalisation with B.1.617.2, and a single dose may also offer high protection.

Chart below is from… (red lines are mine)
Separate data presented by Public Health Scotland also point to strong protection against B.1.617.2 after two doses, with minimal reduction compared to B.1.1.7.
Strong efficacy after two doses is also supported by the latest figures from Bolton, which show case rates among the over-60s (78% have two doses) low and stable, despite a sharp acceleration among younger, less-vaccinated age groups.
The key take-aways:
• Yes, there are signs B.1.617.2 has some ability to evade protection against infection, but that evasion is on the small side
• Evasion against hospitalisation will be smaller still, if there is any at all
• Two doses offer extremely good protection
Here’s our story again:…
Oh, and a nice little footnote:

After weeks of growing FOMO as dozens of friends and family got their vaccines, I’m now booked in for both doses 💉💉💪💪

It’s nice to have that personal win alongside this good news for the rest of us 😀
Very belated addendum: story was done with @AnnaSophieGross & @SarahNev, two extremely cool heads in a high-pressure situation, and fastidiously edited by @andrewparker67.

The best thing about working for the FT is the colleagues 🙌🙌🙌

• • •

Missing some Tweet in this thread? You can try to force a refresh

Keep Current with John Burn-Murdoch

John Burn-Murdoch Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!


Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @jburnmurdoch

23 May
Lots of questions still bouncing around on vaccine efficacy vs B.1.617.2, so here are some follow-ups to our Saturday morning story:

Thread follows, and @SarahNev and I published a new story last night covering all the details including transmissibility:…
Following our original story, PHE later published more detailed data disaggregated by vaccine.

That data shows our pooled figure of 7% relative drop in two-dose efficacy against B.1.617.2 vs B.1.1.7 comprised a 6% drop for Pfizer, 10% drop for AstraZeneca. Very little difference
Similarly, the 35% relative drop in efficacy after one dose was virtually indistinguishable between the two vaccines.
Read 21 tweets
20 May
Just two quick charts on B.1.617.2 today:

Cases continue to climb in Bolton, Blackburn & Bedford, (known B.1.617.2 hotspots), though rate of acceleration in Bolton has slowed slightly, and test positivity there is flat, suggesting surge testing is playing a role in 📈
Continued increase in those areas would be a concern, and it’s worth noting rises in neighbouring Bury and Burnley too.

B.1.617.2 not believed to be dominant in either of these areas, but Sanger data is now 12 days old so that may have changed.
Nonetheless, the same chart shows that high prevalence of B.1.617.2 is by no means a guarantee of prolonged resurgence.

Hounslow, Nottingham and Sefton are all places where B.1.617.2 is believed to be dominant, and yet their upticks reversed and now appear as brief blips.
Read 8 tweets
17 May
NEW: latest update on B.1.617.2 in UK



First, today’s Sanger data on variants at local level. On the surface, this doesn’t look good. Cases of non-B.1.617.2 are in decline, but those red peaks are the variant sending overall rates climbing
To state the obvious: that pattern is not what we want to see, and if things keep going in that direction, we could see national cases rapidly climb again.

But there are a couple of reasons to pause before assuming we’re going to see those peaks steepen and proliferate.
First, the Sanger data is sequences with specimen date before May 8.

We’ve got more days of data since then. It’s not broken down by variant, but it can show us what’s happened to total cases in those areas since May 8.

Answer: growth rates have slowed, in some cases reversed
Read 18 tweets
16 May
Good, measured thread from @JamesWard73 as ever.

If B.1.617.2 does prove to be more transmissible, we may need to keep things like indoor masking and tests for entry to large events for a while beyond June 21.
My thoughts:
• No, that wouldn't mean "lockdown never ends". No, it wouldn't be curtailing freedom. It would be a very small compromise for a very large benefit
• As vaccination rates continue to climb further into the year, those few remaining measures could then be eased
• It's still entirely possible any transmissibility advantage will prove to be much smaller than some have estimated. In that event, June 21 plans can proceed as planned
Read 4 tweets
14 May
Here's the latest from @AnnaSophieGross and I on the Indian variant, digging into how serious a threat it is currently believed to pose…
One thing I think it's important to be clear about is that public health officials and epidemiologists are looking extremely closely at this stuff.
To the extent that policy has not followed one particular path or another, it's because the people looking at the evidence have yet to determine where it points. This is the scientific method, not complacency.
Read 7 tweets
14 May
NEW: this chart is important

It’s early days, but there are signs that the vaccines may be working against the Indian variant B.1.617.2

Resurgences in Bolton & Blackburn are so far confined to younger people. Cases remain low & flat among the mostly-vaccinated older population.
(We must also note that in the past, the higher levels of social mixing you typically see among younger people have led cases to rise among them first before climbing in the older groups, so vaccines are not the only thing that can cause this. We need this pattern to hold)
What about in India, where the variant originated and is believed to be dominant?

Age-stratified data on cases & deaths here is very patchy. But what little there is also hints at a vaccine effect: share of cases/deaths taken up by the elderly (the most vaccinated) is falling 📉
Read 14 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!