Our statistical re-analysis of the Bangladesh mask trial data with @ChikinaLab and @beenwrekt has been published in Trials (@MedicalEvidence).

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trialsjournal.biomedcentral.com/articles/10.11… The Bangladesh trial was a big lift and to date the only cluster randomized trial of masks to generate any publicly available data. Another pre-registered trial in Bangladesh by the same authors was suspended, and a pre-registered trial in Guinnea-Bissau never reported.
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The most pressing questions about the COVID pandemic don't come in the form "can X happen?".

I was surprised at how little quantitative information this article contains, especially when we actually do have high quality data on reinfections.

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https://twitter.com/apoorva_nyc/status/1526191168169680898

The ONS survey tracks reinfections through surveillance testing among its random sample of participants. Even though the recent Omicron waves, the observed reinfection rate has been 1 per thousand or so days.

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ons.gov.uk/peoplepopulati…

As a growing number of people criticize continued restrictions on children and young people, the responses hurdled back are not defenses of still concealing faces from weeks-old infants or making 6 year olds eat lunch silently and wear masks while they learn to read, but this:
1/ Some are pure-style assertions that "these people are bad, dying is bad, COVID is not over, I am on the other team".

Others have gone full-blown connect-the-dots conspiracy, trying to uncover the mystery of why people care about young people's day-to-day experiences.
2/6

The pre-registration for the next phase of the Bangladesh mask trial (@Jabaluck etc) has been posted.

The good: it will probe a bias-resistant endpoint that should be much less dependent on subjective survey responses.

Two important criticisms follow:1/8
clinicaltrials.gov/ct2/show/NCT05… 1) The new phase of the trial still doesn't have any placebo intervention (like, say, education only).

One of the things our re-analysis of their previous study showed is that staff and participants were subject to big differences in study behavior.
2/8
arxiv.org/abs/2112.01296

In the pandemic's 1st year, failing to focus resources and attention on the oldest+most vulnerable in society meant young people faced excessive restrictions that were senseless from a public health perspective.

In the 2nd year, it meant inordinate levels of preventable death.

https://twitter.com/jburnmurdoch/status/1488084513829924867

Commentators on here spend a lot of time talking about low-stakes controversial policies whose only merit is that they scratch a political itch.

Meanwhile the actual failure to vax and boost the oldest (and even LTC) populations goes largely unmentioned, except by "contrarians".

This article is remarkable.

As it discusses, the trials for a 2 dose vaccine in 6 mos-5 year olds failed. But now the FDA seems keen to just grant emergency use authorization anyways, while data from trials of a 3-dose regimen are still a ways out.

1/

washingtonpost.com/nation/2022/01… The next thing to watch for will be mandates for under 5's, for a vaccine under emergency use authorization in a low risk population whose only trial failed.

Meanwhile the US has some of the lowest vaccination and booster rates among the most vulnerable populations.

2/

A lot's happened these past years relevant to how we think of the effects of "misinformation" and how to combat it. There was FB censoring lab-leak posts for a year before backtracking, there's Rogangate; there are also weird conspiracy theories about vaccines/5g/etc on SM.🧵
1/ The term misinformation is often abused, and deployed to belittle what is actually legitimate disagreement or uncertainty.

But claims that are scary and have no basis in truth do spread on SM and have large effects on important individual decisions.

The problem is real. 2/

The fast pace of recent decisions surrounding the use of boosters shots in low-risk populations comes amid a backdrop of significant expert dissent, and has been facilitated, in part, by bypassing scientific advisory committees.

1/

washingtonpost.com/outlook/2021/1… It is surprising that against this backdrop, some universities (including, just today, @CarnegieMellon) have announced booster mandates for students, whose age make the risk/benefit calculation of boosters especially questionable, in part b/c of myocarditis events.

2/

Quick thread about re-randomization in randomized trials, illustrating the following two simple points:
*) re-randomization for balance is sometimes fine and doesn't affect significance thresholds
*) re-randomization for balance can sometimes cause big artifacts.

1/14 First scenario, consider a clinical trial, where we randomize individuals independently (by individual coin flip, say) to treatment or control groups.

What if we re-randomize until the two groups have exactly the same size?
2/14

This blog post discusses our re-analysis of the recently released data from the Bangladesh mask trial (with @ChikinaLab and @beenwrekt).

An accompanying short note is linked from the blog (arXiv link later).

Thread what we find: 1/

https://twitter.com/beenwrekt/status/1466411435450195970

We carried out simple analyses of this data using standard nonparametric paired statistical tests.

Through this lens, there are highly significant effects on behavior, but the primary outcome (symptomatic seropositivity) is not significant. 2/..

The authors of this study are doubling down on @Jabaluck's "guesstimate" of the # of lives masks would save in the U.S. based on their (impressive, sorely needed) cluster trial in Bangladesh.

There are many reasons this guess is speculative to the point of not being useful.
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https://twitter.com/WesPegden/status/1434889868249812996

Apart from the obvious things about translating a finding which was highly context specific (the benefit concentrated in particular ages and in villages using a particular mask type) to a completely different context, one cannot make these estimates ignoring epidemic dyanmics. 2/

Everyone should look at the remarkable work done in this cluster randomized trial.

They found that an intervention which increased surgical mask uptake in community settings significantly reduced SARS-CoV-2 infection among older adults.

A thread.
1/6

https://twitter.com/Jabaluck/status/1433036923610742789

Most people's 1st tendency is to claim studies like this support what they already knew. In reality, the study had specific and not necessarily intuitive findings.

The study even collected predictions from experts, and found that they failed to predict the study outcomes!
2/6

On Friday, epi-Twitter exploded with urgent discussion of an MMWR on an isolated incident in which 1 teacher infected an unusual number of students.

Receiving much less attention was an MMWR on the same day of lower case rates all last year in LA schools than in the community.1/

https://twitter.com/CDCgov/status/1431314357598789640

At the time of this writing, the MMWR with data had 74 retweets and the MMWR on that one time this one crazy thing happened had 1.1K retweets, many from serious people claiming that this report affected in some fundamental way our understanding of COVID-19 risk in schools.
2/

One idea that has not been discussed much is the question of whether regulators have a special role to play in deciding when coercive measures can be used to increase uptake of vaccines.

In practice the hurdle for this has just been EUA, not even full approval.
1/ I think it is worth thinking about what principles should guide the decision of when coercive measures are ethically appropriate and whether regulators should play a role in adjudicating when that bar is crossed.

2/

Just a reminder that (unlike for existing vaccination regimens) there are no trials quantifying a clinical benefit from boosters.

It's remarkable to see the decision portrayed here as one being made based on conversations between political leaders.

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cnbc.com/2021/08/27/bid… Needless to say, politicians that have already made the decision to push forward with early boosters have an incentive to sell this decision to others as a wise and prudent one. Indeed, after implementing this decision, trials would not serve a helpful political purpose.

2/

It's helpful to make claims about likely effectiveness quantitative. Instead of "boosters likely work", how about "boosters likely reduce hospitalizations/etc by at least X%"?

Instead of "masks should work in schools", "I think masks reduce cases in schools by at least X%".

1/5 A claim you think something works, without quantifying how well you think it works, is barely even scientific, since it fails to be falsifiable; one can always disclaim negative findings as underpowered to find smaller and smaller effects.
2/

We should always be cautious not to inappropriately infer causality from correlations via confirmation bias.

But this survey-based paper, which did not measure in-school cases (let alone transmission) did not even find significant *correlations* with student mask policies. 1/

https://twitter.com/linseymarr/status/1428349438150385670

The authors of the paper do not even discuss effects of student masking in the body of the paper.

Note that if we were really determined to infer direct causality from these results, one of the strongest findings would be "desk shields cause infection in household contacts".
2/

This decision seems to reflect a common fallacy; trying to reason about whether we "need X" just based on what things are like without X, rather than how much X will do to help.

It's surprising to see it at play in a decision of such consequence.

1/

washingtonpost.com/health/2021/08… What is gained by making this announcement now, before we know whether boosters would be beneficial in the broader population?

It's hard to imagine that this won't feed fears of many vaccine-hesitant people.

How many first shots lost is one pre-announced booster shot worth?
2/

Without supporting data, how does one decide which demands on other people are reasonable to help one feel safe?

Can one expect their kids' school to only allow attendance of children whose parents promise to wear masks at home, to reduce risk of onward transmission in school? Household transmission risk is a key component of community transmission risk.

*Your* in-home precautions protect *me*.

But we don't make these demands of ourselves. Why is that?

Is it because we don't care about COVID death or illness, or helping others in our community?

One aspect of the discussion of randomized controlled trials is that a lot of people underestimate what it is possible to study (ethically and practically) in this framework.

1/19 One of the most obviously incorrect misconceptions would be that if one knows a condition is bad, it is unethical to trial interventions intended to prevent or treat the condition.

But a moment's reflection reveals this is almost always the setting in which RCT's are done.

2/

I keep coming back to this article from last May, from @mgtmccartney.

Trials would eventually get wielded as very effective weapons in some situations (vaccine trials, the RECOVERY trial, ...) and not at all for the vast majority of NPIs.

1/4

theguardian.com/commentisfree/… The instinct not just of politicians but also scientists to defend how we've reacted (not just in the short term: claims that NPI trials aren't needed persist, 1.5 years into the pandemic) have left us perhaps less inclined towards evidence-based interventions than ever before.
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