NWR new zero tolerance covid thread

People who are taking the trouble to wear masks will be taking the trouble to do other things also.
Exactly that, which is why I always imagined that the measure was to a large extent behavioural. Which makes it not one whit less valid.
It doesn't seem to be expected any more but when things first started to open up I found myself playing the piano wearing a mask. I found it surprisingly liberating, a bit like playing behind a screen.
 
Masks steam up my spectacles, are slightly disorienting and seem to give others a false sense of bravado when assessing distancing.
Wearing a mask when required is more than anything about decent behaviour and being willing to muck in just a tiny little bit for the general good. This would not change one iota were masks shown to be completely useless at stopping infection.
If they were shown to be useless I would stop wearing one and might suggest that others do their "Virtue signalling" some other way.
Each to his own.
 
Masks steam up my spectacles, are slightly disorienting and seem to give others a false sense of bravado when assessing distancing.

If they were shown to be useless I would stop wearing one and might suggest that others do their "Virtue signalling" some other way.
Each to his own.
I’m partially (and apparently increasingly) deaf. I hadn’t realised quite how much I lip read. Masks have been a total nightmare in this regard. I frequently cannot understand or hear people. So the sooner we are rid of them the better. The longer they are around the more they will simply become the norm regardless of whether they are necessary or effective.

I also consider them pretty impolite given the contemporary and historic role of the face in all manner of everyday communication.
 
Full article is here.
...
"Mask wearing and covid-19 incidence—Six studies with a total of 2627 people with covid-19 and 389 228 participants were included in the analysis examining the effect of mask wearing on incidence of covid-19 (table 1). Overall pooled analysis showed a 53% reduction in covid-19 incidence (0.47, 0.29 to 0.75), although heterogeneity between studies was substantial (I2=84%) (fig 5). Risk of bias across the six studies ranged from moderate to serious or critical."
So only six studies of which two had potential serious or critical bias. So a rather misleading headline and commentary.
Thanks for the link.

If we exclude the two high risk of bias papers, Doung-Ngern et al and Krishnamachari et al (Table 1), the rest four papers are Bundagaard et al, Lio et al, Xu et al, and Wang et al. The later three concludes significant effect and the first one shows a rather large bar, let's say it's inconclusive (Figure 5). That's 'Mask wearing and covid-19 incidence'
And then, next paragraph, the paper says:

"Mask wearing and transmission of SARS-CoV-2, covid-19 incidence, and covid-19 mortality—The results of additional studies that assessed mask wearing (not included in the meta-analysis because of substantial differences in the assessed outcomes) indicate a reduction in covid-19 incidence, SARS-CoV-2 transmission, and covid-19 mortality. Specifically, a natural experiment across 200 countries showed 45.7% fewer covid-19 related mortality in countries where mask wearing was mandatory (table 1). Another natural experiment study in the US reported a 29% reduction in SARS-CoV-2 transmission (measured as the time varying reproductive number Rt) (risk ratio 0.71, 95% confidence interval 0.58 to 0.75) in states where mask wearing was mandatory.
A comparative study in the Hong Kong Special Administrative Region reported a statistically significant lower cumulative incidence of covid-19 associated with mask wearing than in selected countries where mask wearing was not mandatory (table 1). Similarly, another natural experiment involving 15 US states reported a 2% statistically significant daily decrease in covid-19 transmission (measured as case growth rate) at ≥21 days after mask wearing became mandatory, whereas a cross sectional study reported that a 10% increase in self-reported mask wearing was associated with greater odds for control of SARS-CoV-2 transmission (adjusted odds ratio 3.53, 95% confidence interval 2.03 to 6.43). The five studies were rated at moderate risk of bias (fig 2)."


So here we have five more papers all at moderate risk of bias.

All together, I am not surprised that the authors of this paper concluded:
"Current evidence from quantitative analyses indicates a benefit associated with handwashing, mask wearing, and physical distancing in reducing the incidence of covid-19. The narrative results of this review indicate an effectiveness of both individual or packages of public health measures on the transmission of SARS-CoV-2 and incidence of covid-19."

I guess Guardian over simplified when they summarised this paper, based on what they want to present. We might call that media bias, but I probably won't say it's misleading. Facemask wearing is most possibly effective in preventing Covid infection, and facemask mandate was shown effective in multiple natural experiments. Those are what this paper suggest.
 
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People who are taking the trouble to wear masks will be taking the trouble to do other things also. Establishing which behaviours have what effects is remarkably difficult. Without randomisation, it's often impossible.
As we discussed here awhile (last year?) ago, a randomisation facemask trail during pandemic would have ethical issue, and because it cannot be blind, randomisation won't solve the behaviour bias (wearing mask itself might change people's behaviour).
But if we look at all the studies, say the natural experients on facemask mandate (see the paper mentioned above), the outcome is for the whole region. And if there was indeed an influence on behaviour but still contributed into the covid case decrease, why not? The real goal is to reduce covid infection/hospitalisation/death, that piece of thing in front of one's nose alone working or not, is just our little scientific interest.
 
Masks steam up my spectacles, are slightly disorienting and seem to give others a false sense of bravado when assessing distancing.

If they were shown to be useless I would stop wearing one and might suggest that others do their "Virtue signalling" some other way.
Each to his own.
When you invoke 'virtue signalling' you lose any argument that might have been, Ray.
 
Thanks for the link.

If we exclude the two high risk of bias papers, Doung-Ngern et al and Krishnamachari et al (Table 1), the rest four papers are Bundagaard et al, Lio et al, Xu et al, and Wang et al. The later three concludes significant effect and the first one shows a rather large bar, let's say it's inconclusive (Figure 5). That's 'Mask wearing and covid-19 incidence'
And then, next paragraph, the paper says:

"Mask wearing and transmission of SARS-CoV-2, covid-19 incidence, and covid-19 mortality—The results of additional studies that assessed mask wearing (not included in the meta-analysis because of substantial differences in the assessed outcomes) indicate a reduction in covid-19 incidence, SARS-CoV-2 transmission, and covid-19 mortality. Specifically, a natural experiment across 200 countries showed 45.7% fewer covid-19 related mortality in countries where mask wearing was mandatory (table 1). Another natural experiment study in the US reported a 29% reduction in SARS-CoV-2 transmission (measured as the time varying reproductive number Rt) (risk ratio 0.71, 95% confidence interval 0.58 to 0.75) in states where mask wearing was mandatory.
A comparative study in the Hong Kong Special Administrative Region reported a statistically significant lower cumulative incidence of covid-19 associated with mask wearing than in selected countries where mask wearing was not mandatory (table 1). Similarly, another natural experiment involving 15 US states reported a 2% statistically significant daily decrease in covid-19 transmission (measured as case growth rate) at ≥21 days after mask wearing became mandatory, whereas a cross sectional study reported that a 10% increase in self-reported mask wearing was associated with greater odds for control of SARS-CoV-2 transmission (adjusted odds ratio 3.53, 95% confidence interval 2.03 to 6.43). The five studies were rated at moderate risk of bias (fig 2)."


So here we have five more papers all at moderate risk of bias.

All together, I am not surprised that the authors of this paper concluded:
"Current evidence from quantitative analyses indicates a benefit associated with handwashing, mask wearing, and physical distancing in reducing the incidence of covid-19. The narrative results of this review indicate an effectiveness of both individual or packages of public health measures on the transmission of SARS-CoV-2 and incidence of covid-19."

I guess Guardian over simplified when they summarised this paper, based on what they want to present. We might call that media bias, but I probably won't say it's misleading. Facemask wearing is most possibly effective in preventing Covid infection, and facemask mandate was shown effective in multiple natural experiments. Those are what this paper suggest.
Thanks Po. Much better to have someone qualified look at these things.
 
It ought to be clear that no-one is suggesting that mask wearing should be continued were it to be proven useless, but it hasn't been.
I think the real point of difference is not that - which we can all agree on - but when the tipping point occurs between usefulness and the need to mandate them. Things are rapidly changing over the water and obviously might do here. For myself there would have to be a considerable movement in hospital admissions and deaths to bring them back.
 
Speaking only for myself, I try to signal virtue as frequently as possible - some would argue more frequently than I actually exhibit it.

I remain in the borderline fundamentalist pro mask camp (or at the very least - I choose to signal that here...) but I think @Eric Burch and @Gareth Germain make very good points, and certainly I would find it hard to condemn them if they chose to signal their virtue in a different way.

It's only a small benefit but I have a sense that due to this pandemic we are, in general, becoming more conscious of the importance of air quality.

It does seem to me (and again, I know that other, smarter people on the forum hold different views) that the WHO and others' decision to give out misleading anti-mask propaganda at the beginning of the pandemic - "for our own good" - has had thoroughly catastrophic results. Not just in the number of unnecessary deaths, but in fomenting so much distrust.
 
You sound like my dear departed great aunt, Leon, who decalared that she was "all in favour of racism" - believing it to mean that we should have as many people of different races in our society as possible! I nearly posted a link to an article about Virtue-Signalling before I realised that it was from The Spectator - and that would be signalling of a different sort entirely!

I'm not sure how significant the WHO thing was. Many people were always going to consider themselves able to judge for themselves how sensible masks were - a little knowledge, and all that.

Gareth - you seem to imply that they've gone. That might be true in London, but up our way, they're still very common indeed, with 90% wearing them in supermarkets.
 
It does seem to me (and again, I know that other, smarter people on the forum hold different views) that the WHO and others' decision to give out misleading anti-mask propaganda at the beginning of the pandemic - "for our own good" - has had thoroughly catastrophic results. Not just in the number of unnecessary deaths, but in fomenting so much distrust.

Is that really the case though Leon? Isn’t it more that we’ve been exposed to misleading pro-mask propaganda since last summer? Prior to spring 2021, the WHO, CDC and our own Chief Medical Officer all agreed that masks were ineffective and possibly even harmful when used incorrectly.

I’d be very interested to see any studies prior to Covid that concluded face masks are effective in reducing the transmission of respiratory viruses. Studies were done but as far as I can see none of them reached that conclusion. Happy to be proved wrong if there are any.
 
Here are some personal notes about my experience of catching Covid:

I tested positive for Covid at the beginning of October. Lateral flow tests (LFTs), two in sequence, showed a thin line again the ‘T’ marker. Confirmed the next day with a PCR test. I continued to do LFTs each day until going negative again at around day 9. At the peak the T line would show solid before the test liquid had even a chance to reach the control (C) line.

Symptoms – running/blocked nose, sinus, fatigue and temporary lose of taste and smell. But no coughing or any sign of spreading to the lower respiratory system. All cleared up, including return of taste and smell, within 3 weeks. All very minor symptoms in the grand scheme of things. Wine tasted like vinegar for about a week.

Prior to infection I had been double vaccinated with the AZ vaccine. I also opted for the antibody test. The first, taken immediately after infection, show the presence of antibodies most likely from the vaccine. A second taken 4 weeks later detected antibodies from both infection and vaccination (IgG tests)

It now feels like a massive weight off my shoulders. Although I’m still careful – wear a mask on the train and tube and take LFTs whenever going into the office or visiting my elderly parents, I’m so much less anxious going out now. Of course, no guarantee I won’t catch the wretched virus again, but it seems unlikely it will cause me serious grief. And yes, I’ve got my booster booked for the end of this month.
 
Exactly that, which is why I always imagined that the measure was to a large extent behavioural. Which makes it not one whit less valid.
It doesn't seem to be expected any more but when things first started to open up I found myself playing the piano wearing a mask. I found it surprisingly liberating, a bit like playing behind a screen.
Indeed. It might very well be that wearing a mask is beneficial partly by being a helpful reminder to do other things.

On a different note, muttering silently at people, from behind one's mask, is also surprisingly liberating. I can't believe I'm the only person to have discovered this.

As we discussed here awhile (last year?) ago, a randomisation facemask trail during pandemic would have ethical issue, and because it cannot be blind, randomisation won't solve the behaviour bias (wearing mask itself might change people's behaviour).

Cluster randomisation would have been a perfectly reliable technique for testing and quantifying a whole host of things, from different mask wearing and track & trace strategies through to approaches to schooling (done successfully here, in fact). Nor is the lack of blinding a problem: it might be that mask-wearing merely helps remind people to do other things, as Tom suggests, but as he also says, that's fine. We don't really want to know the impact of masks so much as the impact of getting people to wear them, which is the actual intervention available. The evidence for using alcohol gel to clean one's hands in hospital isn't, oddly, based on the impact of using alcohol gel. It's based on the impact of putting gel dispensers by patients and asking people to use them, which is a different thing. Does the difference matter? It does, but less so than knowing that the overall intervention works.

With masks, there's no need to adopt any particular extreme binary case beforehand; one could pick two middling strategies and compare them - one type of mask versus another, say - with the results being used to suggest which direction one's next trial should progress in. The ultimate conclusion of the history of medicine is that the impact of interventions can't be figured out by theory and rational thought and expert opinion and wisdom, only by reliable experiments. The implications of that lesson have seeped quite far into medical thinking, but not far enough, and haven't seeped nearly as far in other realms. (In other parts of public policy, for example - the father of evidence based medicine, Archie Cochrane, often cited educational policy or sentencing in order to prevent re-offending as interventions that ought to be subjected to proper trials but which were inappropriately, and therefore harmfully, decided without them).

Cluster randomisation of such things is unacceptable chiefly because of over-estimation of our ability to reason them out without experiment. We breach ethics far more often by failing to test hypotheses than we do by testing them. I spend most of my waking life wearing a mask and do so quite happily, but I would very much like to have better data quantifying what impact it has. Should we all wear masks forever in this way to reduce general transmission of respiratory diseases? Quite possibly we should, but I don't see how we can properly decide without reliably quantifying the impact of doing so. Would it save one life a year in the UK (most wouldn't think it worth the societal expense), a hundred (some would, some wouldn't) or a hundred thousand (most everyone would)? It seems too important a question to be decided without good evidence. In the absence of good evidence we can at least fret about not having such evidence, and refrain from too much certainty.
 
Gareth - you seem to imply that they've gone. That might be true in London, but up our way, they're still very common indeed, with 90% wearing them in supermarkets.
I don’t think I was implying that. But yes it’s certainly less than 90% in London. On the tube it varies between very low (late at night and afternoon) to probably 60-75% at peak times.
 
I'm not sure how significant the WHO thing was. Many people were always going to consider themselves able to judge for themselves how sensible masks were - a little knowledge, and all that.
indeed - very hard to be sure, as we can't really run an alternate version of the last couple of years and find out what happened. It is important to remember, though, that the first lockdown happened in the UK due to popular demand - the government bent to our will, not the other way round. It is hard not to conclude that, had trust not been squandered, we would have had very different outcomes.

Certainly (and I appreciate my view on this is doubtless tinted by that subset of media I choose to consume) it seems that the leaders of New Zealand absolutely avoided the "we're lying to you for your own good" strategy, and managed to maintain much more trust, and had much better outcomes, both clearly in terms of total deaths (7 deaths / 1m population, vs our 2,100) and also in the ongoing trust in their institutions.

Unrelated - once again, I am reminded how lucky we are to have actual experts in this place, who are so generous with their insights. Thank you.
 
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