Need a bike repair after crashing? Bizarre cycle lane outside Evans shop; MORE riders out of Giro with Covid as rain wreaks havoc; Pubs to stay open for longer during World Championships in Scotland; Maintenance mishaps + more on the live blog!

Paul J wrote:

"Could the race organisers have reinstated the mask mandate quicker" Come on road.cc, why are you pushing this nonsense? The evidence is masks in community use have little effect.

Citation required, I think.

Another Molotov cocktail, squire?

chrisonatrike wrote:

Another Molotov cocktail, squire?

Yeah, sorry, I should learn from my mistakes...

(It just annoys me that someone can come on here spouting all sorts of f-ing nonsense and if anyone tries to call them on it, or even engage with them, then the rabbit hole opens and it just goes (more) insane).

brooksby wrote:

(It just annoys me that someone can come on here spouting all sorts of f-ing nonsense and if anyone tries to call them on it, or even engage with them, then the rabbit hole opens and it just goes (more) insane).

I am an evidence-based person. I gave a statement based on evidence. You asked for the citation, I gave it.

Yet you see fit to resort to ad hominem, and you make claims that are factually incorrect. I have NOT spouted nonsense - indeed, if you think my initial statement on mask efficacy was such, then that is indicative that you simply are poorly informed about the evidence base, and so perhaps you should refrain from such comments.

chrisonatrike wrote:

Another Molotov cocktail, squire?

Thanks, and a fresh can of worms whilst you're at it, please.

Exactly that. What evidence is he pointing to exactly?

The gold standard for evidence of efficacy of medical interventions are systematic reviews of trials carried out to the standards of the Cochrane Library's reviews (its researchers lead the way and helped to define many of the standards and practices for systematic reviews). The Cochrane Library itself has a number of revisions of its own review on physical interventions and ILIs, which it started pre-pandemic. The latest version of which is here: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006207.pub5/...

The latest revision incorporates both the Danmask trial and the Bangladesh trial, carried out over the pandemic, into the data, along with the prior body of evidence on other ILIs.

.

Paul J wrote:

The gold standard for evidence of efficacy of medical interventions are systematic reviews of trials carried out to the standards of the Cochrane Library's reviews (its researchers lead the way and helped to define many of the standards and practices for systematic reviews). The Cochrane Library itself has a number of revisions of its own review on physical interventions and ILIs, which it started pre-pandemic. The latest version of which is here: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006207.pub5/... The latest revision incorporates both the Danmask trial and the Bangladesh trial, carried out over the pandemic, into the data, along with the prior body of evidence on other ILIs.

You edited your post since you first posted it - what did you change?

Anyway, I see that the most recent version of that study at https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006207.pub6/... and that it is a meta study

Quote:

We included 11 new RCTs and cluster‐RCTs (610,872 participants) in this update, bringing the total number of RCTs to 78. Six of the new trials were conducted during the COVID‐19 pandemic; two from Mexico, and one each from Denmark, Bangladesh, England, and Norway. We identified four ongoing studies, of which one is completed, but unreported, evaluating masks concurrent with the COVID‐19 pandemic.

Many studies were conducted during non‐epidemic influenza periods. Several were conducted during the 2009 H1N1 influenza pandemic, and others in epidemic influenza seasons up to 2016. Therefore, many studies were conducted in the context of lower respiratory viral circulation and transmission compared to COVID‐19. The included studies were conducted in heterogeneous settings, ranging from suburban schools to hospital wards in high‐income countries; crowded inner city settings in low‐income countries; and an immigrant neighbourhood in a high‐income country. Adherence with interventions was low in many studies.

and that their conclusion includes this statement

Quote:

Our confidence in these results is generally low to moderate for the subjective outcomes related to respiratory illness, but moderate for the more precisely defined laboratory‐confirmed respiratory virus infection, related to masks and N95/P2 respirators. The results might change when further evidence becomes available. Relatively low numbers of people followed the guidance about wearing masks or about hand hygiene, which may have affected the results of the studies. 

I really don't think they are saying that "masks don't work".

brooksby wrote:

You edited your post since you first posted it - what did you change?

I fixed typos, missing words, misordered words, precision. Readability stuff.

brooksby wrote:

I really don't think they are saying that "masks don't work".

Sorry yes, v6 is the latest. I had linked to v5 for some reason, thanks.

They are indeed not saying "masks don't work" (it's usually impossible to rule out /any/ effect of a treatment, given clinical trials have noise). Note also you are quoting their editorial conclusion. To be precise, on masks this is their quantitative conclusion from the systematic analysis (which is done according to standardised methods):

Cochrane Review wrote:

Wearing masks in the community probably makes little or no difference to the outcome of influenza‐like illness (ILI)/COVID‐19 like illness compared to not wearing masks (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.84 to 1.09; 9 trials, 276,917 participants; moderate‐certainty evidence. Wearing masks in the community probably makes little or no difference to the outcome of laboratory‐confirmed influenza/SARS‐CoV‐2 compared to not wearing masks (RR 1.01, 95% CI 0.72 to 1.42; 6 trials, 13,919 participants; moderate‐certainty evidence). Harms were rarely measured and poorly reported (very low‐certainty evidence).

Emphasis there is mine, note "makes little or no difference".

Which is exactly inline with my statement at the top of this thread "masks in community use have little effect" - cause... where do you think I got this from? (this very Cochrane review).

https://www.health.com/cochrane-review-do-masks-work-7112631?scrlybrkr=5...

IanGlasgow wrote:

https://www.health.com/cochrane-review-do-masks-work-7112631?scrlybrkr=5...

Cochrane Reviews are gold standards. Just ask any MD with an education from last 15 years about the regard these are held in.

Bloggers, presumably with emotional attachments, trying to wave away systematic meta-analysis are just examples of "The Science" (which is not science).

Oh, and it is worth bearing in mind that in medicine, that a treatment that has less than 50% efficacy is not considered an effective treatment.

The Danmask study was a well-designed study, which was powered to reliably detect a 50% or greater effect, within certain covid prevalence figures - which were met during the study. And it could not find a statistically significant effect. So any effect in that setting is certainly less than 50%.

The Bangladesh study was quite large, it had a confidence interval from no effect to (iirc) ~10% (I forget the /exact/ figure, but v close to that). I.e. no statistically significant, but any effect is upper-bounded by that ~10% figure (to 95% probability).

The Cochrane meta-analysis puts it at 16% or worse RR.

So it's pretty certain that masks are *not* an effective treatment, within the customary meaning of "effective treatment". And further, any effect there is very likely below 17% RR - that's really low.

Also, unlike a lot of other treatments in medicine, where we expect the treatment to cure the subject, the RR of a mask is temporally dependent. The longer the time, the worse the RR again.

give it up. masks are like tinfoil hats. people either believe they work or don't. the evidence is irrelevant. 

Well, like the WHO (January update) and the US CDC (still advising masks this May) I may not have quite caught up.  However the virus has - and now - like many other viruses this one may have now mutated its way to something most can live with.

From your comments on the other thread it sounds like a bit of 20/20 hindsight in respect to the pandemic here?  After all, if you want to rely on the Cochrane studies their previous 2020 version of this says:

Cochrane Library in 2020 wrote:

The high risk of bias in the trials, variation in outcome measurement, and relatively low compliance with the interventions during the studies hamper drawing firm conclusions and generalising the findings to the current COVID‐19 pandemic.

... So these reviews weren't super helpful then.

Any ideas for next time - or is it "just let nature take its course"?

Paul J wrote:

Also, unlike a lot of other treatments in medicine, where we expect the treatment to cure the subject, the RR of a mask is temporally dependent. The longer the time, the worse the RR again.

Well - I'm pretty sure a lot of treatments are considered useful despite not curing the patient, or even preventing the condition from progressing.

That was my point about this being a good bet at the beginning.  After all - wait long enough and all patients (and non-patients) are dead!  Time matters - both personally and for population-level health.  It's almost certainly worse if all you health staff fall sick at once compared to the same numbers having an illness but spread over more time.  That has effects wider than the disease itself.

There is literally nothing else they can do. It's not going to cause harm, and any form of reduction in transmission is a bonus.

Hygiene Is another easy to do thing, might not help with COVID, but is proven to work with other respiratory infections, and there is no better defence against food poisoning, especially Norovirus.

Marginal gains...

ktache wrote:

There is literally nothing else they can do. It's not going to cause harm, and any form of reduction in transmission is a bonus.

Hygiene Is another easy to do thing, might not help with COVID, but is proven to work with other respiratory infections, and there is no better defence against food poisoning, especially Norovirus.

Marginal gains...

That's what I thought back then - if there's no evidence of harm maybe "why not".  And pick up some incidental benefits of more thoughtful / hygenic behaviour - which may be unrelated to Covid but helpful especially at a difficult time.

However if it's somehow shown in a more general way that for air-bourne respiritory viruses masks aren't helpful I think Paul J would have a point - going forward *.  Especially in medical settings and even in terms of money / time spent advertising to the general population.

On the other hand we certainly bought lots of PPE at extravagant prices (oddly often sold by friends of MPs) which turned out to be useless for other reasons.  Avoiding that would have been good.  Although possibly unavoidable in practice given our system of government and human nature.

* It seems Paul J has a much bigger complaint having IIRC suggested several interventions as not only not being useless but actively harmful.

ktache wrote:

There is literally nothing else they can do. It's not going to cause harm, and any form of reduction in transmission is a bonus.

That's something I also thought at the beginning of the pandemic, and I went along with masks on the "well, the evidence with ILIs is that they don't work, but... as there's no harm, why not give it try?" basis.

Then I spoke to people close to me who are hard of hearing, who rely on lip-reading to navigate in daily life. Masks were making life harder for them. Then I heard from colleagues (quite pro-mask ones) who were getting rashes around their ears from the straps, and were asking others for tips.

So this notion of "no harm" is incorrect. There are harms.

When an intervention (often called a treatment in trials) has no good evidence of efficacy, but you learn of clear evidence of harm, then it is time to stop advocating for it.

Paul J wrote:

Oh, and it is worth bearing in mind that in medicine, that a treatment that has less than 50% efficacy is not considered an effective treatment.

The Danmask study was a well-designed study, which was powered to reliably detect a 50% or greater effect, within certain covid prevalence figures - which were met during the study. And it could not find a statistically significant effect. So any effect in that setting is certainly less than 50%.

The Bangladesh study was quite large, it had a confidence interval from no effect to (iirc) ~10% (I forget the /exact/ figure, but v close to that). I.e. no statistically significant, but any effect is upper-bounded by that ~10% figure (to 95% probability).

The Cochrane meta-analysis puts it at 16% or worse RR.

So it's pretty certain that masks are *not* an effective treatment, within the customary meaning of "effective treatment". And further, any effect there is very likely below 17% RR - that's really low.

Also, unlike a lot of other treatments in medicine, where we expect the treatment to cure the subject, the RR of a mask is temporally dependent. The longer the time, the worse the RR again.

You're supposed to put the mask over your face, including your mouth and nose. Not wear it like a jockstrap.

Oh, and wearing a mask is not 'treatment' so applying those tests is just fucking moronic.

I think that applying the same criteria for effectiveness to a community intervention versus a medical treatment is somewhat fallacious. A treatment has to make a person healthier, balancing risks from potential side effects etc. Wearing a mask has no side effects that I am aware of and to me a 10% reduction in case numbers during a pandemic is a really good outcome. Having said all that making riders at the Giro wear masks before and after a stage seems unlikely to be effective bearing in mind they are then breathing heavily in close proximity to each other during the stage.

SimoninSpalding wrote:

Having said all that making riders at the Giro wear masks before and after a stage seems unlikely to be effective bearing in mind they are then breathing heavily in close proximity to each other during the stage.

I believe it's more to prevent transmission to race officials, spectators, journalists et cetera; obviously you're correct in that six hours in the peloton is going to make masking around each other for a few minutes before and after fairly ineffective.

Paul J wrote:

The gold standard for evidence of efficacy of medical interventions are systematic reviews of trials carried out to the standards of the Cochrane Library's reviews............

No, they used to be the gold standard, now they are regarded as just as unreliable as any other paper.  This is because when they've looked at cycle helmets, they broke every rule they've got by using blatantly biased researchers and an extremely narrow range of original studies.

I thought I'd posted this once, but it seems to have disappeared.

eburtthebike wrote:

No, they used to be the gold standard, now they are regarded as just as unreliable as any other paper.  This is because when they've looked at cycle helmets, they broke every rule they've got by using blatantly biased researchers and an extremely narrow range of original studies.

I thought I'd posted this once, but it seems to have disappeared.

You posted it on the other article. Do you want to link to something that details these "rules broken"?

One criticism that has been made of Cochrane is that their rules are a little biased favourably to the side of interventions - i.e., that they're more likely to find something works. This has been made more in the context of those wanting to paint them as "friendly" towards pharmaceutical companies trials.

AFAIK, this isn't really a fair criticism of them. And it's more just to do with the issues around having pharmaceutrical companies be the main funders of and organisers of the largest pharmaceutical trials (which gives them ways to bias results a little in their favour; from simply not publishing negative results [meant to be fixed now by registration of trials] to designing trials to be biased [e.g., excluding cases of a disease in the treatment arm of a trial if they occur within X days of treatment - obviously biased practice, but commonly done]).

Paul J wrote:

The gold standard for evidence of efficacy of medical interventions are systematic reviews of trials carried out to the standards of the Cochrane Library's reviews............

eburtthebike wrote:

No, they used to be the gold standard, now they are regarded as just as unreliable as any other paper.  This is because when they've looked at cycle helmets, they broke every rule they've got by using blatantly biased researchers and an extremely narrow range of original studies.

Do you want to link to something that details these "rules broken"?.

That which can be asserted without evidence can be dismissed without evidence. (Christopher Hitchens)

eburtthebike wrote:

That which can be asserted without evidence can be dismissed without evidence. (Christopher Hitchens)

You're asserting that those doing the Cochrane reviews on cycle helmets  "broke every rule they've got", and providing no evidence for that assertion. It can therefore be dismissed without getting into the weeds of how any researcher whose research goes against your gut feeling is a shill for Big Helnet. 

Brauchsel wrote:

eburtthebike wrote:

That which can be asserted without evidence can be dismissed without evidence. (Christopher Hitchens)

You're asserting that those doing the Cochrane reviews on cycle helmets  "broke every rule they've got", and providing no evidence for that assertion. It can therefore be dismissed without getting into the weeds of how any researcher whose research goes against your gut feeling is a shill for Big Helnet. 

And it has been asserted that Cochrane Reviews are the gold standard without any evidence.

eburtthebike wrote:

Brauchsel wrote:

eburtthebike wrote:

That which can be asserted without evidence can be dismissed without evidence. (Christopher Hitchens)

You're asserting that those doing the Cochrane reviews on cycle helmets  "broke every rule they've got", and providing no evidence for that assertion. It can therefore be dismissed without getting into the weeds of how any researcher whose research goes against your gut feeling is a shill for Big Helnet. 

And it has been asserted that Cochrane Reviews are the gold standard without any evidence.

I suppose someone needs to run a metastudy to check if it is really the case.