mindstalk | Entries tagged with face masks

Importance of fit-testing your mask and not relying on "the seal feels good": ~75% of people who failed a fit test, passed a seal check. Jump to Table 3 to save time: https://journals.sagepub.com/doi/full/10.1177/0310057X20974022

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And finally, a very long paper on why some vaccines suck and others are one-and-done. Had a lot of new info even for me, even without getting too technical. https://deplatformdisease.substack.com/p/some-vaccines-are-one-and-done-why Some highlights:

I've been right! Reproduction dynamics are a key part to how good our protection is; if a virus reaches infectiousness faster than our memory B cells respond, we can't control it. Delta was faster than original covid and Omicron even faster.

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"Flu" in Scotland is so bad that many NHS doctors are voluntarily wearing masks, probably surgical face masks, to protect themselves, and suggested visitors do too. Let's count all the problems with this:

1) "so many doctors and nurses were falling ill from the virus that frontline workers were voluntarily wearing protective face coverings to avoid contracting the infection", 'described flu patients waiting for “hours and hours” to secure places on wards' -- despite all this crisis, no actual policy change for infection control, just individual mask wearing. Because apparently trying to keep your own workforce from being infected is too much for hospitals.

2) The article never mentions covid or coronavirus, despite the virtual certainty that many, if not a majority, of those "flu" cases are in fact covid-19. But hey, if you don't test, it's not there, right?

3) Three years ago, a British hospital did as close to a high-power controlled test as we're likely to ever get, basically proving that FFP3 masks are far more protective than surgical masks. (Quick summary: in surgicals, the covid ward workers got infected a whole lot, while non-covid workers only got infected at the community rate. In FFP3s, the covid workers got infected at the same rate as the non-covid workers and community.) Despite that, the doctors and nurses reported are likely wearing... surgicals. Certainly the blurry photo is only of baggy blues.

4) Reminder that influenza virus is easy mode. The same controls in 2020 that generally struggled with or outright failed to contain SARS2/covid-19, wiped out one or two entire flu seasons, with the B/Yamagata strain being wiped out by accident.

We have the technology. Mass respiratory infection is a choice, now. Our (across multiple countries) hospitals are choosing to permit mass infection. Our public health agencies are choosing to let infection spread without saying anything. Our health care workers are (mostly) choosing to get infected.

On Bluesky a few days ago, some NYC people said that blacks were the demographic most masking these days. This surprised me, as I would have guessed Asians, from my own observations and vague memories of polls. Thing is, I feel gut level observations are pretty junk statistics, whether mine or someone else's, especially for anything complicated. ( Read more... )

Took BART in at 8 AM. BART made various changes on Sep 11, running a bit fewer trains at peak (in exchange ending the 30 minute headways on weekends), and shorter trains, 6 instead of 10 cars. Between all those factors, it was actually pretty population, unlike other BART rides of the past year. Masking: under 50%, above 10%.

Took the new (to me) T line one stop, to Chinatown. Perhaps over 50% masked. Seemed self-sorted: first car mostly Chinese, mostly masked, plus some masked or not whites; second car a clump of non-masked people.

Chinatown: lots of masks, mostly surgical. The big park was full (as usual) of elderly Chinese people, mostly masked as they played cars or catted with each other. Meanwhile, big groups of mostly white tourist would get led through, unmasked.

I took a couple photos relevant to this:

https://www.flickr.com/photos/mindstalk/53202670783/in/album-72177720311347196/

https://www.flickr.com/photos/mindstalk/53202670843/in/album-72177720311347196/

8 bus up to Pier 39 area, after I discovered and explored the Jeremiah O'Brien Liberty Ship museum. Out of hundreds of tourists at Pier 39, I saw one mask. Let me remind you that AQI was in the 100-150 range. I did see a few locals masked: couple of Chinese shopkeepers, a security guard(!), some information guy? (yellow-green reflector vest, answering questions.)

Also saw the sea lions, woot.

BART home, 4 PM. Absolutely packed, I never got to sit down. Maybe 1/3 masked.

I'd guess largely a mix of KN95 and surgicals, some trifolds that could be KF94 or the better N95s.

Even in Berkeley, where many people still wear masks vs. covid, and even on a day when you can literally see and smell the smoke... outdoor masking is still week. At first very weak, I passed nearly a dozen people, before seeing one bicyclist in some cloth mask. It got better later, though some were in surgical masks. Peak was a couple in 3M 8511s, valved cup respirators. And pushing a stroller; I deeply regret that I did not think to look at what protection they have might have provided a child.

Odor molecules are often very small, and not filtered by a particulate respirator; "rotten egg" smell is H2S, hardly bigger than a water molecules. But I guess a lot of smoke smell is carried by big particles, because there was a huge odor difference between having my mask sealed or not.

(3M 8210 today, classic white cup. KF94 inside my home, where the purifiers seem to be struggling against leakage.)

I just went to my local Japanese grocer. Many of the customers still masked, in various varieties -- more the Asians clustered around the fish counter than the whites I saw leaving as I entered. All of the staff masked. But...

The staff were all in surgicals. And largely wearing double surgicals -- blue surgical over blue surgical. Whhyyyyy. This does nothing except make it harder to breathe. "Double masking" was supposed to be tight-fitting _cloth_ mask over surgical, to pin the surgical around your face, like a poor man's mask brace.

(There's also a dental thing of surgical over N95, but I think it's to protect the N95 from patient fluids. That's fair.)

(My mask: fit-tested 3M Vflex.)

So, in this season of tripledemic disease and canceled surgeries, what masks are y'all wearing?

Since I'm back in the US, I've upgraded my shopping mask from tightened KF94 to 3M 95s, mostly Aura but sometimes Vflex from a friend. Been trying DIY qualitative fit tests as well, to assure myself of good fit.

So although I've mostly avoided wildfire smoke, here I am in Mexico City, where the air is bad by default, with AQI around 150 today.

AQI is a weird non-linear index. For PM2.5, the main culprit here:

ug AQI (ug = micrograms per m3)
5 21
10 42
12 50
16.3 60
20 68
25 78
30.6 90
35.4 100
40 112
50 137
55.4 150
100 174
250 300
500 500

5 ug is the WHO's new recommended maximum for air safety, down from 10, or the EPA's 12. You can see AQI starts out at 4x ug, becomes more like 3x for the region of modest concern, and ends up nearly linear. Also that AQI 150 is over 10x the WHO safe limit (after converting to ug), or 4x the EPA's.

Thing is, I've got respirators. Even a 90% reduction turns that 55.4 ug down to nearly 5 ug. 99% reduction turns even AQI 500[1] into safety. Should be nice and safe to go outside.

Buuut I spent the day reading inside, in my bedroom with the air purifier on. And wearing a mask too (3M 8511, valved) because why not, it's actually pretty comfortable. I have stuff I want to do inside, I might as well do it during the hell period.

[1] The official EPA scale maxes out at 500, though I think I saw reports of 2000s when Australian cities were being wreathed in smoke last summer, so either my memory is wrong, someone extended the scale, or AU has their own AQI scale.

https://www.hindustantimes.com/cities/500-what-a-maxed-out-aqi-means/story-Zg0gUMnSKCZKEAu0iry62J.html seems to say the health damage plateaus... also that India's safe level is 60 ug. Eek.

I went for a walk today, first time leaving the house in 3 days due to work and rain. Hardly anyone was around, so I was unmasked apart from checking out a couple of shops. All was well, after an hour on my feet and a bit more on the clock, until, I sneezed! And my nose began to run, needing blowing! Had I gotten covid while buying food 3 days before, or was there another explanation?

Checking pollen websites, one said Grass: Low, while another said Grass: High. I don't know why the difference, but either way, grass has entered the field. And I'm sensitive.

So out came the mask again, and I left it on, apart from pulling it down to blow my nose. Which, after some unmeasured period, stopped being required, despite my still being among the grass and trees of a large park.

Woot, go masks.

Vancouver pollen levels are "VERY HIGH". The named species aren't the ones I've been tested for (but what is one to make of "Cedar, Juniper, etc."?), but I've still been 'enjoying' some itchy eyeballs and nose blowing, especially after opening my windows or being outside unmasked.

Silver lining: I'm getting very good evidence of masks working, as the past two days I've spent 2.5 hours outside without problems. Hell, I seem to be suffering more from pollen leaking into the apartment despite closed windows (or coming off my clothes...) than from being out.

This also makes me more confident that the mask is protecting me from particulates when walking along a car sewer.

Though pollen is kind of easy mode: 10-200 microns.

Relevant papers:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8278371/ (Masks work, 14 patients subjected directly to grass pollen.)

https://pubmed.ncbi.nlm.nih.gov/34534761/ (Masks work, pandemic questionnaire)

https://www.jaci-inpractice.org/article/S2213-2198(20)30867-9/fulltext (Masks work, especially for 'intermittent' sufferers, Israeli nurse experiment)

As the world rushes to surrender to covid-19, declaring it over even while case and death remain high or even rising, I feel the quixotic urge to remind people it doesn't have to be that way, and we could be cutting person-person transmission by 98%.

Getting high filtration material isn't hard now, any decent respirator or ASTM surgical mask qualifies; many respirators have tested as much better than their official certification of 94-95% at 0.3 microns, with over 99% filtration.

Getting good fit is much chancier, and most of us don't have access to professional fit testing, or even a DIY nebulizer test. But various results indicate that a reasonable attempt at fitting a respirator will be at least 88% protective, and using a surgical mask with a mask brace/fitter, even DIY with rubber bands, will get into the 90-95% range. And you can use mask braces with respirators too!

So you can get at least 88%, possibly close to 95%, if you want. And if everyone were wearing 88% masks, letting 12% through, what would get between two people would be 0.12^2, or 1.44%

This wouldn't stop all community transmission, if people go to restaurants/bars/gyms/parties a lot. Hell, if they do that, it probably wouldn't stop most community transmission, since being loud and unmasked is very very risky. But it would make other places safe, for the vulnerable and risk averse. And could crush covid if we masked and skipped dining out etc for a few weeks, far short of a full lockdown -- or as I put it, good masks are lockdowns for noses.

An anti-masker question I've been seeing going around Twitter is "did you wear masks before 2020?" Implying that if they're a good idea now even with covid vaccines, they would have been a good idea then against cold and flu, and if we didn't wear them, we're inconsistent or irrationally afraid.

Well no, I didn't wear masks, nor any American I knew. But it's not because we considered masks and made a decision not to wear them. It's because we never considered them at all. We didn't reject it as an option, we didn't even have it as an option.

I have a bit less excuse than most: I did know that the Japanese would wear masks when sick. But even so, when I flew from Seattle in Feb 2020 with my last cold, it never occurred to me that wearing a mask was something I could do. If someone had brought it up, probably I would have wondered where I could even find a mask, especially on short notice. If someone had handed me one and suggested I wear it on the plane to be courteous to others, quite likely I would have worn it! But without that, it wasn't even on the mental menu.

Likewise, when I was suffering through various years of hay fever, "buy masks and wear them against pollen" never occurred to me. No choice was made, it just was.

Now, though? Now I do have multiple masks -- respirators -- that are comfortable and should filter at least 90% of particles. (The material itself should be better than 99%, the uncertainty is about fit.) I'm used to wearing them. I also now know that some Californian friends *did* have N95s, for protection against wildfire smoke. I can envision using masks as protection against pollen and PM2.5 pollution. Now I'd say "if I'm on a plane and sick, why *wouldn't* I wear a mask? Or if someone on the plane is coughing behind me? If I'm walking along a busy road, why wouldn't I want to cut the particulates I'm breathing by at least 90%? Why were we so tolerant of breathing filthy air?"

So, Japanese people wear masks a lot. Probably the main thing that got them through most of the pandemic, along with avoiding "the three Cs" and good contact tracing; Japan never had lockdowns. (And was worst in class for rich Asian countries for most of the pandemic, too.) But they already had the custom of wearing masks when sick, to protect others. So I wondered, did that make an observable difference in flu seasons, say?

( Long )

So what's the final verdict? It's *possible* that Japan has a much lower flu burden than the US: the strongest case for that is comparative hospitalizations per capita, with an 8-fold ratio. There's also a 4x ratio in deaths -- though that might be mostly canceled out if the US is estimating 'flu-associated' deaths (pulmonary and pneumonia and such, not just respiratory) and Japan isn't. OTOH medical visits don't seem dissimilar, given the greater likelihood of Japanese people to go see a doctor. But if flu transmission is similar, then Japan must have a much *lower* chance of being hospitalized for flu, which would be odd. Epidemiology is hard! Especially as a layman sticking my nose in and not knowing the messy details.

And of course even if there is a big difference in cases or deaths, I've done nothing to show that masking is responsible, though intuitively, sick people wearing masks when out of the house should help a lot.