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The neuroinvasive potential of SARS-CoV2

ncbi.nlm.nih.gov

261–270 of 298 posts

Re: The neuroinvasive potential of SARS-CoV2

#261

Earlier quoted context omitted.

The problem is that a mask that isn't regularly replaced and handled very carefully actually increases your chances of catching the virus, via a mask->hand->face transmission.

Wait, how? If it's on the mask wouldn't it be on the face if the mask wasn't there? What process puts viruses on masks but not faces?

The best practice is to not touch your face with your hands. Wearing a mask may increase the frequency you touch your face due to discomfort

Re: The neuroinvasive potential of SARS-CoV2

#263
post #17

Earlier quoted context omitted.

Yes, only a N95 or better mask would protect you from incoming, as opposed to outgoing, viruses, and these masks are both impractical for everyday wear and need to be conserved for public health users.

I have a small box of N95 masks in my shop - bought last summer for dust protection. When is the right time for me to put them on my family. Part of this is how long will they last before I must replace them. Or should I put them on eBay for a million dollars and hope I life to enjoy my new found wealth?

N95 filters, if cared for(ie no compression/ripping damage), work until you can't effectively breathe through them any more.

Re: The neuroinvasive potential of SARS-CoV2

#264
post #42
post #17

Earlier quoted context omitted.

I have a small box of N95 masks in my shop - bought last summer for dust protection. When is the right time for me to put them on my family. Part of this is how long will they last before I must replace them. Or should I put them on eBay for a million dollars and hope I life to enjoy my new found wealth?

Or you could donate them to your local hospital since there is a shortage. I’m not sure they would take them, but it’s worth considering.

There isn't a shortage if you're a hospital. There's a run on the retail supply, and retail restocking will be very limited, if at all. But your local hospital is fine.

And it would have to be apocalyptic for them to accept a box of medical equipment from some guy wandering in.

Re: The neuroinvasive potential of SARS-CoV2

#265
post #258
post #154

Earlier quoted context omitted.

Why would they not remote work?

Who cares for software engineers in bandanas anyways if you can have bank clerks in bandanas! And even that would hardly look weirder than in surgical masks. Color-coordinated bandanas with a company logo pin?

Bank customers in bandanas would probably be a good way to get shot by a security guard in a bandana. The days of Butch and Sundance aren't that far behind us!

Re: The neuroinvasive potential of SARS-CoV2

#266
post #228

Earlier quoted context omitted.

I think that different sources are using different definitions of "effective" here. If a simple surgical mask cuts down transmission rates by 50% that isn't anywhere near good enough for health workers working with sick patients every day. But it might still make a significant improvement in your chances of getting infected and, combined with social distancing, might drop the R0 below 1. Hence why Chinese and Korean…

TL:DR: The most effective use of disposable masks for blocking germ transmission is by the people with the germs who might pass them to this without but at risk. Surgical masks are meant to protect surgery patients from the medical staff and the droplet-encased germs they emanate. N95 masks are meant to protect the wearer from particulate matter (harmful dust) in the air, specifically those particles over 30 microns.…

> N95 masks are meant to protect the wearer from particulate matter (harmful dust) in the air, specifically those particles over 30 microns. SARS-CoV02 is roughly half the size, so as an aerosolized virion, as opposed to droplet-suspended virions, they may have limited effect.

The N95 filters are tested with particles at 30 microns, but that doesn't say anything about their effectiveness against other particles.

3M, naturally, has released some information on this exact topic [1] which goes into a fair bit of detail on the various methods by which masks effect filtration. The tl;dr version is that there are several ways by which filtration is achieved that generally overlap and work towards providing effective protection well above and below 30um. There is generally a small dip in the transition between two primary methods which creates a specific size range where filtration is less effective.

Whether that's an issue depends on your definition of "limited effect". For the masks they tested, that dip generally occurred around 0.04-0.1um. Even in the worst case scenario, however, the worst masks tested were still filtering ~94% of the particles (in a mask that only claims 95% effectiveness to begin with). The linked document has coronaviruses listed as being about 0.125um in size, which has them falling toward the end of the dip where the mask is trending back towards 100% efficacy.

(For what it's worth, they also have the distribution of droplet sizes in a sneeze and they are all smaller than 30um as well. However they're still in a range where the mask will be about 100% effective.)

Which is all to say I certainly wouldn't describe an N95 mask as being of "limited effect".

[1] https://multimedia.3m.com/mws/media/409903O/respiratory-prot...

Re: The neuroinvasive potential of SARS-CoV2

#267

Earlier quoted context omitted.

Yes, only a N95 or better mask would protect you from incoming, as opposed to outgoing, viruses, and these masks are both impractical for everyday wear and need to be conserved for public health users.

Even N95 masks are not fully sufficient. They typically block particles at 0.3 microns or larger, but coronaviruses tend to be smaller, around 0.1 - 0.3 microns. You need an ASTM Level 2 or higher surgical mask to block coronavirus from completely penetrating the mask. That said, any mask is better than no mask, first because it prevents you touching your mouth and nose with potentially infected hands, and second bec…

can't sub .3 microns particles get stuck in the fibers along the way even if they can pass the first (due to turbulent flow)?

Re: The neuroinvasive potential of SARS-CoV2

#268

Earlier quoted context omitted.

I think that the fear was of a mask shortage. Infected quarantined > Potentially Infected COVID-19 contacts wearing masks > Uninfected wearing masks.

Can someone shed some light on the difficulties of producing the "simple" surgical masks? I'm not talking about something that filters the incoming air, but the lame kind that just reduces the amount of liquids you disperse when breathing, coughing, sneezing etc. Are they so high tech you can't just ramp up production? And how many months in advance would you need to ramp it up? We're about 3 months in and nobody got…

Demand is probably relatively (to other products) stable, why would you have been running a factory with unused capacity available to ramp up into for years ?

I read about a hand sanitiser manufacturer ramping up in the UK; by increasing hours, not throughput. And obviously to increase hours you need more staff, training, and maybe to review some policies, local bylaws, and other procedural stuff.

Re: The neuroinvasive potential of SARS-CoV2

#269

Earlier quoted context omitted.

The retina is basically an extension of the brain as well, no? If not, what is the key difference? Do you have a link talking about the atmosphere?

But the retina is not exposed to the outside world. It's got the rest of the eye between it and the air.

Ok, but is brain tissue uniquely infectable compared to eye tissue or something? The ultimate worry isn't that your olfactory bulb gets hurt, it's that the infection reaches deeper into the brain, and I don't get why it's easier to do that from the olfactory bulb rather than from the eye.

Re: The neuroinvasive potential of SARS-CoV2

#270
post #163

Earlier quoted context omitted.

I don't understand what the Wikipedia link is supposed to show. Your eyes are tightly linked to your brain too.

the neuronal terminals leading to a lobe of the brain innervate the nasal mucosa. the optic nerve is hidden behind the eye with a substantial barrier of non nervous tissue in front of it. https://upload.wikimedia.org/wikipedia/commons/thumb/1/1e/Sc...

Can the infection move through nervous tissue more easily than non-nervous tissue?
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