Thanks Esteban, this is what we have here too, safe the masks. So quite possibly they do make a difference people keep denying. Well, denial is what got us into this mess.
esteban wrote:
?You wear the mask even if you are asymptomatic. Even if you don’t cough/sneeze, you are still emitting droplets, just a bit less so (some people speaking emit quite a lot…).
You don’t need to sneeze, or even dribble doesn’t matter if your wearing a mask, in that circumstance. i.e. asymptomatic. If you touch your face, or you touch the mask, which is necessary if you want to wear it, and you touch a hard surface, like say a supermarket trolley or hand rail, the virus will be transmitted, the other person just needs to complete the chain. That IS why we have the lockdown.
It all about using the appropriate precautions for the circumstance, and not creating panic and fear. For example pre landing checks should be done before landing, not after you have landed :-)
Ted wrote:
You don’t need to sneeze, or even dribble doesn’t matter if your wearing a mask, in that circumstance. i.e. asymptomatic. If you touch your face, or you touch the mask, which is necessary if you want to wear it, and you touch a hard surface, like say a supermarket trolley or hand rail, the virus will be transmitted, the other person just needs to complete the chain
Umm, the way I understand it, the primary means of transmission is still droplets/aerosol. You don’t want to have the air in closed spaces (grocery store, factory…) full of floating viruses. Then you really need good respirator + eye protection to stay safe.
The handrails/supermarket trolley is a much lower-probability chain of transmission (can be broken in many places with simple measures), with probably smaller virus loads as well (some loss in each step). Btw, here they stepped up the hygiene by requiring hand desinfection/gloves in all stores that want to remain open – precisely to break this chain.
We will see how this works – it needs responsible behaviour by vast majority of people.
I think I may have posted this article about mask production before – sadly it sounds as if the manufacture of filter material is the rate limiting step.
Apparently you may need as many as 100 masks and respirators per day per patient in ICU so perhaps 1000 masks per stay per patient – I can well believe this. I think the solution has to be along the lines of reusable protective equipment or non-disposable equipment. I have heard of people in some places trying to wear single masks for whole shifts rather than changing them between patients, but this would be against our current guidelines.
I wonder whether there is any alternative to the current devices. I could imagine passing the air through a chamber full of UV light (not Ozone producing though) which might reduce the work of breathing relative to the current masks. The pandemic is a veritable gift to inventors.
esteban wrote:
the primary means of transmission is still droplets/aerosol.
That may well be the case, though I don’t believe the science is at all clear on that point. However if we are talking about aerosol a simple cloth mask is likely to be ineffective, at least that is what the WHO says.
Just to be clear I would happily wear a cheap mask it if was available and was simply asked to wear it and I would not need legislation to compel me. I will wear an old PPE2 mask full of brick dust and virus if i am asymptotic this afternoon when I pop to the shops . My objection is to the proposition that wearing such things in those circumstances are going to solve the problem and should be accepted as fact. IMHO even this lock down is still largely dancing around the problem. Its unlikely to stop the spread, though of course it buys valuable time to come to a sustainable and viable solution.
I could imagine passing the air through a chamber full of UV light (not Ozone producing though) which might reduce the work of breathing relative to the current masks
You very much do want ozone. It kills everything… and disappears in fresh air in seconds. You can take an item out of a UV+ozone steriliser which is full of ozone (the sort routinely used by “cosmetic practitioners”) and a few seconds later you can’t smell it. And the smell threshold for ozone is 1 or 2 orders of magnitude below the long term toxicity level. Also ozone gets everywhere, whereas UV gets only where light can reach.
One certainly could sterilise masks, but perhaps not for wearing somebody else’s, just in case 
I think there would still be health concerns about getting people to inhale Ozone. If you are passing air through a chamber then there should not be a pathway for it to avoid passing through the chamber so it is not like trying to disinfect a laptop where there will be lots of nooks and crannies. If you used a coarse filter you would stop people from potentially inhaling coarse particulate matter that might shield pathogens from the UV light. There are lots of water sterilisers available using a similar principle.
Ted wrote:
However if we are talking about aerosol a simple cloth mask is likely to be ineffective
I think we are talking past each other.
I am not talking about assured protection. I am talking about significantly reducing the probability of transmission (from the wearer), and somewhat reducing the probability of getting the disease (for the wearer). Wearing a mask alone does not decrease your probability of getting the disease (staying home/avoiding contact would do it much better) significantly, but if everybody wears a mask, the reduction is significant. Perhaps/hopefully to the point that a semblance of quasi-normal life (e.g. Japan) and economy can be maintained. Of course, I am not sure about the last sentence.
WHO’s stance is a different matter – I think it is intended to keep the supplies for medical professionals. If so, I think they (WHO) are shooting themselves in a foot and reducing their credibility. The people are not THAT stupid.
What is needed is a layered defense. The masks are just one of the layers – a simple one with a relatively low economic cost. I don’t believe anybody is touting them as a cure-all solution.
Today’s briefing of our (Slovakia) PM was actually rather interesting: He said that currently (with the relatively relaxed lock-down) we are trying to slow the spread/maintain it in a manageable level so that we have time to prepare and avoid overwhelming the health system. However, maybe we should try to build a consensus for a TOTAL lockdown of everything for about 3 or so weeks(hm, realistically, looking at China, maybe up to twice that), which would allow to actually get rid of the virus, and might be economically and socially less painful than many, many months of quasi-lockdown. I was quite literally stunned to hear a politician say things that actually make sense.
The East German city of Jena will make wearing a mask compulsory for grocery shopping and using public transport:
https://www.thelocal.de/20200331/first-large-german-city-makes-wearing-a-face-mask-mandatory
Well, you may call me an “imperialist running dog” (diguozhuyi de zougou), but I’m not altogether ready to believe the figures produced by our own government, let alone by the PRC.
It seems that the UK government (principally May, Hammond and Hunt), the civil service, the health service and the emergency services concealed the dismal results of Exercise Cygnus, so why should anyone trust them now?
