The good thing about this story is that any time I see someone sharing it as evidence that wearing masks cuts Covid incidence by 53%, I know they haven’t read the paper it’s based on and aren’t fussed about the quality of evidence as long as it produces the right number 🙃
What do I mean by this?

Let’s start by saying that yes, we have good evidence that masks reduce Covid incidence 😷🦠📉😀

BUT it points to nowhere near a 53% reduction. As today’s @bmj_latest states, the best evidence — randomised controlled trials — point to more like a 10% cut
Indeed, here is the BMJ’s take on today’s paper:
• Most of the studies included in the meta-analysis from the Guardian story are poor quality and subject to major biases
• We need more & better research [like the mask-wearing RCTs which have consistently found a smaller effect]
To conclude
• Based on best evidence, masks cut incidence by ~10% ✅
• So masks are a good, low-cost measure to use on top of vaccines ✅
• If you care about finding the most effective interventions, don’t share obviously misleading numbers based on "very low quality" evidence
Here’s the study behind the Guardian "53%" story…

And here’s today’s BMJ editorial setting out the substantial limitations to that study, the dearth of good studies + evidence, and what the best current evidence on masks actually is…
Finally: this stuff grates so much because it’s often people on "my side" sharing what is essentially misinformation.

We would rightly call this out if people on "the other side" did it, and we diminish trust in statistics, science and journalism when we fall into the same traps

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More from @jburnmurdoch

15 Nov
NEW: @UKHSA study finds Pfizer booster is extremely effective against symptomatic infection, both compared to the unvaccinated and to those with 2 doses…

Whether first 2 doses were AZ or Pfizer, a Pfizer booster sends vaccine efficacy up to 93-94% 💪 Image
Study was on people aged 50+, comparing those boosted ~5+ months after dose 2, to those @ 5+ months unboosted.

AZ efficacy was 61% after dose 2, waning to 44% @ 5 months.

Pfizer was 82% after dose 2, waning to 63% @ 5 months.

2 wks after Pfizer booster, both groups -> 93-94%!
Best way to think about booster impact is not to look at going from 44 to 93 with AZ, i.e roughly doubling, but invert the numbers and go from (100-44) to (100-93), i.e from relative risk vs unvaxxed of 56% to just 7%

That’s an 87% increase in protection *relative to two doses!* Image
Read 8 tweets
11 Nov
NEW: England has recorded 18 successive days of week-on-week declines in cases, its longest sequence of declines since February, suggesting its autumn/winter wave may have peaked…
Crucially, hospital admissions, patient numbers and deaths are now also trending downwards, as the fall in case numbers has shifted from being youth-driven into all age groups.

These acute indicators look to be topping out at 10-20% of last winter’s peak levels.
A key factor here has been England’s booster rollout.

Antibody levels in the oldest groups (vaccinated the earliest) had been slowly eroding as the months passed, but in the last 5 weeks they have shot back up as third doses have gone into arms 💉💉💉💪💪💪
Read 18 tweets
5 Nov
NEW: Covid cases, hospitalisations & deaths on the rise again across Europe, with rates of all three metrics surpassing the UK in many countries

Starting in the west: Belgium, Netherlands & Germany in particular experiencing sharp increases in not only cases but ICU & deaths too
And the picture worsens as we move further east.

In central Europe, cases were a fraction of UK levels over summer, but have now rocketed past, with ICU occupancy and deaths also climbing fast.

Vaccine coverage is generally lower here than in western Europe.
In eastern Europe, the situation is dire.

Romania, Bulgaria & Latvia all set new records for daily deaths in recent weeks, and deaths are 10x current UK levels.

In much of western Europe it can feel like the pandemic is an echo of its past self. Try telling that to the east
Read 8 tweets
3 Nov
🚨all of is free to read today, so if you like the glimpses you see on Twitter but want to go deeper, now's your chance!

Beyond Covid, read our best work on climate, politics, inequality & culture. Apparently there's even stuff on economics & finance! 🚨
Throughout the day I'll be sharing links to some of the pieces I've enjoyed most this year, starting with this brilliantly clear column by @TimHarford demonstrating how a carbon tax would be a game-changer in the battle to curb emissions
Another great piece to read 🔓#FTfreetoday:

Off the back of Squid Game and Parasite, @crsdavies took a deep dive into the huge success story that is South Korea’s entertainment export industry, and the decades of strategising that led to this point…
Read 5 tweets
2 Nov
NEW: as of the end of September, Russia has recorded 753,583 excess deaths over the course of the pandemic.

This is almost 4x its official reported Covid death toll, and is second only to the US in absolute terms among countries with reliable data…
• Russia’s vax rates remain stubbornly low, only 33% fully-vaxxed amid widespread mistrust
• Society largely carrying on as normal despite 2k daily excess & 1k daily reported deaths

Full details in the story from @polinaivanovva, me & @mroliverbarnes…
We’ve also updated our excess deaths data for all countries:…
Read 6 tweets
1 Nov
One of the most startling Covid charts I’ve made in a long time, on vaccine inequality:

Rich countries have given out more booster shots in the last 3 months, than poor countries have given out total doses all year.

@donatopmancini’s story:…
In rich countries, just 18% of people aged 12+ are yet to have any dose, and 5% have now had a third dose.

In poor countries, 94% are yet to have a single dose.
The result?

Stark inequality in outcomes.

In countries with ~70% fully vaccinated, about one in 250 cases results in death.

At 50-60% fully vaxxed, around one-in-75 results in death.

At 10-15% fully vaxxed, it’s one-in-25.

And in parts of Africa, as high as one-in-15.
Read 5 tweets

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