Masks might slow it, but they're everywhere in the Bay Area, and cases are rising faster than ever, and we're setting new records for new cases, so "just wear a mask in public" isn't enough.
I think the argument is that masks are an essentially effortless tactic, and if people can't even bother to put them on and the government doesn't seem to care very much, then what hope is there for more effective measures?
I don't live in the UK, just explaining how I read this comment.
> I think the argument is that masks are an essentially effortless tactic
Masks are effortless, but there is also a lot of reason to believe they are not nearly as effective as was sold to people in the early summer.
At some point we get into "just wear a crucifix to ward off the Devil" territory of superstition.
Masks are obviously helpful at preventing transmission of some illnesses, but I've seen enough evidence that Coronavirus spreads via aerosol to not really trust the things.
That is not an accurate summary of the study. Emphasis mine:
> Limitation: Inconclusive results, missing data, variable adherence, patient-reported findings on home tests, no blinding, and no assessment of whether masks could decrease disease transmission from mask wearers to others.
> The recommendation to wear surgical masks to supplement other public health measures did not reduce the SARS-CoV-2 infection rate among wearers by more than 50% in a community with modest infection rates, some degree of social distancing, and uncommon general mask use. The data were compatible with lesser degrees of self-protection.
I don't think any public health experts are saying "wear a mask and you'll be safe", they're saying "if everybody wears a mask, that will slow the infection rate". A study of a community with "uncommon general mask use" does not dispute this.
Finally, I don't think it's clear that a randomized controlled trial is the best method to answer this question. Aside from ethical concerns, you can't give someone a placebo mask. Shouldn't we assume that people will behave differently when they're wearing a mask?
I made an accurate summary of the study. From the Results:
"Although the difference observed was not statistically significant, the 95% CIs are compatible with a 46% reduction to a 23% increase in infection."
The points you are raising about limitations in no way affect the conclusion of the work. Short of putting infected people in a room with uninfected people, there is no ethical way to test the hypothesis that "masks could decrease disease transmission from mask wearers to others".
But since it's pretty unlikely that masks are effective in one direction only, this is the highest-quality evidence we have that they have no effect in one of the two directions.
> Finally, I don't think it's clear that a randomized controlled trial is the best method to answer this question.
A randomized controlled trial is always the gold standard for an intervention of this sort. But yeah, you can't do one for that hypothesis. So you're stuck with something that is fundamentally un-falsifiable. The best you can do is try to do what people have done so far: look at populations, and see if mask mandates make any difference, or ask people who caught Covid if they wore masks, or do similar things within families.
This is called retrospective cohort analysis, and it is low-quality evidence, at best.
> Aside from ethical concerns, you can't give someone a placebo mask. Shouldn't we assume that people will behave differently when they're wearing a mask?
Yes, we should assume that this might happen. It could well be true that wearing a mask makes people be more careless about distancing, for example. This is called "risk compensation", and is a well-known phenomenon in public health.
It seems to me that you're trying to fight two battles at once.
1. do masks inhibit production of and exposure to aerosols carrying SARS-COV-2? This seems (to me) to me clearly established, and essentially irrefutable.
2. do mask mandates reduce the spread of COVID19? this is an entirely different question, and has almost nothing whatsoever to do with the abilities of masks referenced in (1) above.
I would suggest that we know that the answer to (1) is yes, without doubt, but we have only hand-wavy answers to (2). That's still quite different from what you're claiming.
> do masks inhibit production of and exposure to aerosols carrying SARS-COV-2? This seems (to me) to me clearly established, and essentially irrefutable.
Aerosols? It's far from established. In fact, it's a dubious claim, unless you're far more specific about what you mean by "masks". The best laboratory studies show that properly fitted respirators (i.e. as used in hospitals), can reduce aerosol emissions. But few people are wearing respirators, and essentially nobody is fitting them correctly.
Cloth masks? Surgical masks? Cup masks? About the only claim you can make is that they might reduce heavy droplets and then, only by about 30% or so. There's no reason to believe they have any effect on aerosol emission.
Anyone who has done a mask fitting -- where they put you in a room with vaporized stuff that you can taste to detect leaks -- will tell you how difficult it is to get an aerosol-resistant seal on a mask. The chances that the general public is doing it is 0%.
Data regarding the “real-world” effectiveness of community masking are limited to observational and epidemiological studies.
* An investigation of a high-exposure event, in which 2 symptomatically ill hair stylists interacted for an average of 15 minutes with each of 139 clients during an 8-day period, found that none of the 67 clients who subsequently consented to an interview and testing developed infection. The stylists and all clients universally wore masks in the salon as required by local ordinance and company policy at the time.
* In a study of 124 Beijing households with > 1 laboratory-confirmed case of SARS-CoV-2 infection, mask use by the index patient and family contacts before the index patient developed symptoms reduced secondary transmission within the households by 79%.
* A retrospective case-control study from Thailand documented that, among more than 1,000 persons interviewed as part of contact tracing investigations, those who reported having always worn a mask during high-risk exposures experienced a greater than 70% reduced risk of acquiring infection compared with persons who did not wear masks under these circumstances.
* A study of an outbreak aboard the USS Theodore Roosevelt, an environment notable for congregate living quarters and close working environments, found that use of face coverings on-board was associated with a 70% reduced risk.
* Investigations involving infected passengers aboard flights longer than 10 hours strongly suggest that masking prevented in-flight transmissions, as demonstrated by the absence of infection developing in other passengers and crew in the 14 days following exposure.
Seven studies have confirmed the benefit of universal masking in community level analyses: in a unified hospital system, a German city, a U.S. state, a panel of 15 U.S. states and Washington, D.C. as well as both Canada and the U.S. nationally. Each analysis demonstrated that, following directives from organizational and political leadership for universal masking, new infections fell significantly. Two of these studies and an additional analysis of data from 200 countries that included the U.S. also demonstrated reductions in mortality. An economic analysis using U.S. data found that, given these effects, increasing universal masking by 15% could prevent the need for lockdowns and reduce associated losses of up to $1 trillion or about 5% of gross domestic product.
> in a unified hospital system, a German city, a U.S. state, a panel of 15 U.S. states and Washington, D.C. as well as both Canada and the U.S. nationally. Each analysis demonstrated that, following directives from organizational and political leadership for universal masking, new infections fell significantly. Two of these studies and an additional analysis of data from 200 countries that included the U.S. also demonstrated reductions in mortality. An economic analysis using U.S. data found that, given these effects, increasing universal masking by 15% could prevent the need for lockdowns and reduce associated losses of up to $1 trillion or about 5% of gross domestic product.
All of these studies were conducted on data from the spring, when cases were declining across the northern hemisphere. How are these places doing now?
Anyone who attempted to conduct a similar analysis today would have to credibly conclude that masks have no protective effect whatsoever. But who knows...maybe they slightly alter the slope of the curve. It's impossible to tell without a controlled trial.
The german paper is particularly ironic, given that it was published approximately concurrently with a huge increase in diagnosed cases in the same city, which is now at all-time highs for the year:
> Anyone who attempted to conduct a similar analysis today would have to credibly conclude that masks have no protective effect whatsoever.
Absolutely not the case. It would be just as credible, as has been noted by others in the comments here, to suggest that the major cause of spread is unmasked private gatherings.
> But who knows...maybe they slightly alter the slope of the curve. It's impossible to tell without a controlled trial.
I agree that without controlled trials, it is very difficult to tell definitively. That does not, however, translate into "there are lots of reasons to doubt ..."
Infection with SARS-CoV-2 occurred in 42 participants recommended masks (1.8%) and 53 control participants (2.1%). The between-group difference was −0.3 percentage point (95% CI, −1.2 to 0.4 percentage point; P = 0.38) (odds ratio, 0.82 [CI, 0.54 to 1.23]; P = 0.33). Multiple imputation accounting for loss to follow-up yielded similar results. Although the difference observed was not statistically significant, the 95% CIs are compatible with a 46% reduction to a 23% increase in infection.
No statistically significant protective effect for the wearer, but as the study points out, it says nothing about protection of those around the wearer, which is the commonly accepted reason for mask wearing.
For what it's worth, this doesn't mean anything (by this I mean that literally, you have gained zero bits of information from this result, and should be exactly as confident as you were before the study)
Read the latter half of that sentence again. Think about what it means. You can't just pay attention to the part of the sentence that you like, and ignore the other parts.
Also, I quoted this exact line in a comment below, so I'm not sure how you can credibly claim that I'm "mis-representing" something.
They obviously don't offer 100% protection. Though I've heard a nice analogy by Christian Drosten on the popular German coronavirus podcast:
Imagine you are standing close to someone at a party who starts talking to you. You immediately notice their bad breath (~aerosols). Now imagine they are wearing a mask, then imagine you both are. How much of the bad breath would you still notice in each case? That's the effect of masks.
Those sorts of comparisons are good at making the mechanism or action understandable, but that's about it. The huge thing they miss is if masks only somewhat effective, but people wearing them act like they're moderately effective. The real-world, systemic parts of this is where it gets complicated and interesting.
Lots of things are "effortless tactics". If they don't work, it's just superstition. People will figure it out, and they'll stop believing you. If you have indoor mask mandates, and outside mask mandates, and shut down restaurants, and curfews, etc., and your cases are still shooting up, you're going to have a hard time getting faith in your actions.
So much of what governments are doing in response to this are just cargo cult science. We've had ample time to run proper controlled trials for much of this stuff -- the Danes were able to do so with masks [1], and there was a big study of gyms out of Norway [2] -- it's simply pathetic that our governments mostly haven't bothered.
Masks can make a significant difference when new cases per infection is near 1. Dropping it from 3 to 2 doesn’t matter has that’s still heavy exponential growth, dropping it from 0.5 to 0.25 again doesn’t matter because it’s dropping fast. However dropping from 1.05 to even 0.95 is huge.
In theory, any tiny reduction in infection rate can make the decisive difference when the number of new infections from each existing infection is close enough to one. In practice, this is extremely unlikely to work in the real world because in reality, this is not some universal constant that is fixed at a particular value everywhere by some physical law - it varies from place to place, from job to job, from community to community, and the ones where it's below 1 will end up representing an exponentially smaller fraction of cases compared to the ones where it's above 1 meaning that the overall average won't stay below 1 for long.
Treating R, the number of infections from each case, as though it was the same everywhere is just a way of simplifying the model, but the map is not the territory and we need to be a lot more careful about whether our simplifying assumptions change the overall behaviour of the system being modelled than we have been.
It’s not about an abstract model, there are feedback loops involved. Shutdowns and people’s behavior responds to the number of new infections. Globally across the last 6 months, new infections are close to 1:1 because you don’t exponential growth. Just look at the three waves in the US.
In effect masks buy you a more open environment where people can leave their homes and do more stuff. Further, when locations decide to shutdown that shutdown is more effective.
Nothing I wrote was an argument about masks. I linked to the one RCT on masks (as PPE) done in 2020, to illustrate that it's possible to do high-quality studies of these kinds of interventions, and underline the point that politicians are mostly just guessing, and people can see this.
You're grinding an axe here, but it has little to do with what I wrote.
Did someone claim it was? The name of the game is and has always been suppressing the transmission rate of the virus. Masks are a low impact way to help a little bit towards that goal, nothing more.
I was responding to someone in London saying they don't see most people wearing masks in public places. They didn't explicitly say it was enough, but since that was their main criticism of how London is responding, it read like that.
Here's what Biden said:
> The first day I'm inaugurated to say I'm going to ask the public for 100 days to mask. Just 100 days to mask, not forever. One hundred days.
Again, he didn't say that wearing a mask is enough, but with the 100-day timeline, reading between the lines, he's saying it will drive down the case count.
Same here in Massachusetts. Universal masking since May 6th, the governor even did away with "except of >6ft from others when outside rule" in the beginning of November, and we're seeing more cases than ever.
Melbourne started their lockdown in winter. Everyone obeyed it. It was strongly enforced [1, 2]. They beat coronavirus. And now they can enjoy their summer.
I live in London. At one point in the summer, our covid rates were lower than Melbourne's. But the UK's messaging was confused and contradictory ("eat out to help out", test and trace was shambolic, rules were not enforced). So no one is the least surprised that it has got out of control again so quickly.
[1] My parents live half an hour's drive from Melbourne. Police stopped every car on the highways to enforce no travel, fined the drivers and made them turn back home.
[2] One party of 26 people got busted ordering KFC to the same address and fined $26,000.
I don't think I was, but every journey starts with the first step ;-). I think the Australian confidence of 'having eradicated covid' is misplaced. You can only eradicate a virus if you do that worldwide, and given viruses' capability of mutating, I think that's an unattainable goal.
That's in Sydney, which is over 700km away. It is also nothing like the scale that the UK is dealing with and will hopefully be dealt with by a short lockdown - possibly not even of the entire city of the politicians pull their finger out quickly enough.
Yeah, raarts is trying to burn us by taking this sudden reappareance of a whole 30 cases in NSW seriously. Because here in Australia we take it that seriously.
Short lockdown maybe, back to normal soon, not too many other places will be able to brag about that.
We will be able to save all the lives prior to vaccination that nations with less willpower seem willing to spend.
Firstly, the UK response has been terrible, Australia far better.
However there are several contributing factors and it certainly doesn’t come down to mask use as the primary one as mask discipline in the UK hasn’t been bad in my experience.
This is a seasonal disease (the main reason for the UK summer reprieve), and it’s now summer in Australia, and they have also been far better at quarantines and contact tracing and have used this period wisely to get the disease under control. All these factors matter in a response, and the UK has suffered from panic management and a lack of difficult measures at the right time and is now entering the peak season for this sort of virus so things will get worse for a month or two at least, even with a new lockdown.
> What worked in Melbourne was that 8 months of house arrest for everyone living in the city...
The .au epidemiologists I've heard on NPR have made it clear that what worked in Melbourne was everything they did, including a lockdown and including contact tracing.
If only the UK had the same level of government as Melbourne and Singapore and Japan and South Korea and New Zealand and all the other places that did that...
I'm not sure that's completely fair. Countries vary so much that putting it down to "the government" ignores all the other factors. You're examples are all on the southern hemisphere, with mostly nice weather where people spend more time outside. General population health also has a massive effect. Here in the UK we are a nation of overweight old people, but fat-shaming is a thing so that's only going to get worse.
But those antipodean countries are all coming out of their winter. So they got through the worst of it during the coldest part of the year, with more people indoors, and only now are getting into summer.
Not sure why you are all focusing on my example with the weather. Like I said there are many factors involved here, with the weather being one of them.
I completely agree with your overall point, that there are too many confounding factors to reliably attribute anything to government actions. I guess I just couldn't resist the urge to nit.
the concept of velocity is too hard for people to grasp
they need binary good/bad cause/effect edicts, like children. state and municipal governments are poorly catering to their own velocity based directives, and the juvenile more simplistic expectations of their population.
Every store I've gone in has required them, I've heard mass transit is a lot less crowded and also requires them, and I think county rules mandate them in those cases. I've seen people without them going on outdoor walks, but that's an incredibly low-risk activity.
Yes, she has been tested for active Covid about a half-dozen times with both the fast (15 min) and slower tests. We wanted to make extremely sure she wasn't an asymptomatic carrier who could give it to her elderly parents.
She didn't get tested for antibodies as the health system has far more important things to deal with right now in the US, unfortunately.
I spent a week in a small apartment with someone who had symptomatic Covid. Close contact the whole
time. Neither of us wore masks.
I never got it.
An anecdote means very little, and certainly is not evidence that masks work without controls for every other thing that might have prevented you from getting infected.
