Better masks are obviously better.

> completely ineffective when wet,

As far as I know this is not correct. I remember to have read a study showing quite well that even a wet cloth mask(1) still contains the spread of aerosols surprisingly well. Sure it's far worse then a medical mask of any kinda but still a surprisingly high improvement compared to the no-mask scenario.

> which they get after 15 minutes or so of breathing through them.

In my personal experience this is far from correct, through this depends on the definition of "wet" and the weather.

(1): As long as they are not made of a specific kind of material, which e.g. is often used for bicycle masks and sometimes for scarfs which might from the get to go make thinks worse by splitting the aerosols into smaller lighter ones without stopping them at all.

Sure, there is a reason that in Germany they moved from "any mask" to "medical" mask to requiring FFP2/(K)N95 masks.

I'm just going by the CDC's webpage on masks showing a big red X next to using masks that are wet or dirty.

https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-si...

https://www.cdc.gov/coronavirus/2019-ncov/science/science-br...

> A community-based randomized control trial in Denmark during 2020 assessed whether the use of surgical masks reduced the SARS-CoV-2 infection rate among wearers (personal protection) by more than 50%. Findings were inconclusive,54 most likely because the actual reduction in infections was lower.

This is inaccurate, and should make anyone doubt the judgment of whomever wrote this summary. The paper in question was quite clear that there was no statistical significance between groups:

> 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.

To characterize this as "inconclusive" is misleading at best, dishonest at worst. In general, I find this page to be a highly selective reading of the available literature, which was (and remains) predominantly inconclusive regarding the effectiveness of masks. Even the WHO meta-analysis of mask literature found only a weak positive effect after mixing together the results of studies ranging from cloth masks to respirators, in medical (most of the data) and non-medical settings [2]. This CDC page has instead chosen to lean on a few poorly controlled observational and/or correlative studies, and ignore the higher quality evidence that came before.

[1] https://www.acpjournals.org/doi/10.7326/M20-6817

[2] https://www.thelancet.com/journals/lancet/article/PIIS0140-6...

On top of that they state: "Although the difference observed was not statistically significant, the 95% CIs are compatible with a 46% reduction to a 23% increase in infection."

Which sounds like their saying they can say with 95% confidence that there is between a 46% reduction and a 21% increases, which sounds pretty damn inconclusive to me.

The authors say this:

> The most important limitation is that the findings are inconclusive, with CIs compatible with a 46% decrease to a 23% increase in infection.

This is not saying that that study is inconclusive. It's saying that the protective effect is inconclusive -- masks could be anything from slightly protective, to slightly harmful. The fact that the writer characterizes the entire paper as "inconclusive" is incriminating: it's an editorial bias, a complete misunderstanding of statistics, or a combination of both.

> Which sounds like their saying they can say with 95% confidence that there is between a 46% reduction and a 21% increases, which sounds pretty damn inconclusive to me.

No. They're stating the confidence interval on the point estimate. All point estimates have confidence intervals, and the existence of a confidence interval does not mean that the result is uncertain. To restate basic statistics: the top-line conclusion of the study is that the 95% confidence intervals of the two groups overlap to such a degree that you can't reject the conclusion that they're the same.

There is also the limitation that there was "no assessment of whether masks could decrease disease transmission from mask wearers to others."

The article explicitly states "The findings, however, should not be used to conclude that a recommendation for everyone to wear masks in the community would not be effective in reducing SARS-CoV-2 infections, because the trial did not test the role of masks in source control of SARS-CoV-2 infection."

The study is not inconclusive. The study failed to reject the null hypothesis. That much is definitive.

Whether or not there might be some smaller difference that the study wasn't powered to detect...we don't know. It's still a definitive rebuttal of any claim that "masks reduce personal risk of infection by 50%", and the fact that it's not in the "personal protection" section of the CDC webpage is simply editorial bias. At the very least, this paper is the best study ever performed on masks and SARS-CoV2, and it severely limits any real-world claim of protectiveness.

> There is also the limitation that there was "no assessment of whether masks could decrease disease transmission from mask wearers to others."

The study wasn't designed to do that. It should still be in the "personal protection" section of the CDC webpage, and is not.

And since they are KN95, you aren't taking masks away from medical professionals.

Edit: map is just Sydney.

Australia is currently attempting to contain the spread of the Delta strain.

You can see the map here https://www.health.nsw.gov.au/Infectious/covid-19/Pages/case...

Anecdotally, based on what friends are saying about their neighbourhoods, the major hotspots have lower mask wearing compliance, and possibly compliance on visiting households.

I live in an area with almost no cases. Mask wearing is very common especially indoors. But people are still going to shopping centres. So congregation of people is not a differentiating factor in my opinion. Shops are quite busy during the day and social distancing is less than ideal. Especially with WFH, and cafes and restaurants still open for take away. People hang out outside shops.

I believe testing in my area is also high. When there was a few cases near me, I went to 2-3 testing locations to find the shortest queues. All were packed. People not wearing masks are so far outside, social distancing, in a park exercising with social distancing. There is a lot of different masks. Surgical, cloth, some of those fancier reusable ones.

So maybe masks work well enough to make a difference.

Also I've not seen a single cloth mask particulate test that has tried to reproduce the dampness level of a cloth mask that's been worn for an hour. In any but the driest climates that mask will be damp and much less effective.

And given how few studies have been done on cloth mask efficacy over the last year, it is likely the experts already know that cloth masks don't do much.

My argument isn't that people shouldn't wear masks, it's that now that cheap, plentiful, effective quality masks are available, people are still being told to wear cloth masks. I assume that's the same confusion that got the Senator banned from Youtube.

Neither of those factors are true where I am and there are very few new cases. I don’t deny that there could be confounding factors. But, and I’m using the word literally correctly here, my supermarket is literally operating as normal with social distancing almost impossible. You can’t even walk past someone in an aisle correctly distanced.

And forget about getting vaccinated. It’s very hard to get an appointment here.

I’m not sure what other confounding factor is powerful enough to counteract hundreds of people in close proximity breathing the same air if cloth masks have an insignificant effect.

The difference in populations. If your population is younger, fitter, lighter skinned (and that's just three of the most important of the many factors found in severity of the disease) then there could be the same number of cases in both populations but yours has a higher number of asymptomatic or symptomatic but self-misdiagnosed cases.

Unless both populations are being mass tested weekly? Or do they only get a test if they show symptoms…

A well fit KN95 is drastically preferable, readily available, and highly affordable. No idea why these aren't being promoted as the only safe choice.

It would further decrease the credibility of the government/CDC/Fauci because it would be perhaps the (fourth or fifth?) shifting mask advisory that we have seen in the last 18 months.

basic science: "Anything that reduces droplet velocity and interferes with aerosol dispersion is by definition better than nothing." here are some supercomputer simulations: https://www.youtube.com/watch?v=GAvO_QdO9eM

To be fair, as insufferable as this attitude can be, it's probably necessary in order for progress to happen. It usually drags us in the other direction, though.