Advice on mask-wearing to protect against Covid-19

Forbin said:
Despite the small study size, he found the results "compelling" because there was a "dose response." People who wore masks consistently had a 70% reduction in community transmission, while those who used them intermittently had only a 60% reduction.
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That 70% reduction in transmission may be enough to halt the pandemic:

The basic reproduction number (BRN) of the SARS-CoV-2 coronavirus is thought to be around 2 to 3 (meaning each infected person goes on to infect 2 or 3 others on average).

A 70% reduction in transmission means a reduction by a factor of 100 / (100 - 70) = 3.3

So a reduction in transmission by a factor of 3.3 will reduce the BRN down to 3 ÷ 3.3 = 0.9 or less — which means the pandemic will die out, because pandemics fizzle out when the BRN is less than 1.



Forbin said:
He considered trying to publish this, but decided that it might lead to shortages of masks at the "front lines."
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This is crazy! I understand the need to protect the mask supply for frontline medics; but then if you don't get the message out that universal use of masks may dramatically slow down the pandemic, the frontline medics are going to be so totally overloaded anyway with cases that the hospitals will just collapse.

We need our leaders to call on industry to start manufacturing masks as an emergency priority, like they did for ventilators, so that everyone can have one.
 
Boston hospitals getting ‘game changer’ machine that sterilizes 80,000 protective masks a day

Battelle’s machine, which will be available to multiple hospitals in the region, uses concentrated hydrogen peroxide vapor to decontaminate N95 masks, which are in high demand and offer superior protection to other masks. Under normal circumstances, N95 masks are discarded after each use. With this system, they can be reused safely up to 20 times, according to Battelle.
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https://www.bostonglobe.com/2020/04/02/metro/boston-hospitals-getting-game-changer-machine-that-sterilizes-80000-protective-masks-day/
 
I am eager to hear the update from the WHO on their advice about the general populace wearing masks. The WHO are reviewing some new unpublished evidence from Hong Kong on the efficacy of masks for the general public.

This article (2 April) says:
But a new study in Hong Kong has suggested coronavirus masks could help protect the public from catching coronavirus, it is reported.

A panel of WHO health experts is now set to review the evidence today. That could lead to the current advice changing.

“There is right now a debate about the usefulness of masks,” infections disease expert Professor David Heymann told a Chatham House briefing.
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I hope the WHO don't dilly dally. They reviewed the evidence yesterday.

And the death toll in the UK seems to be doubling every 3 days at the moment.
 
I haven't been able to read the whole thread so this may already have been posted.

CDC's Recommendation Regarding the Use of Cloth Face Coverings, Especially in Areas of Significant Community-Based Transmission

https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover.html

CDC continues to study the spread and effects of the novel coronavirus across the United States. We now know from recent studies that a significant portion of individuals with coronavirus lack symptoms (“asymptomatic”) and that even those who eventually develop symptoms (“pre-symptomatic”) can transmit the virus to others before showing symptoms. This means that the virus can spread between people interacting in close proximity—for example, speaking, coughing, or sneezing—even if those people are not exhibiting symptoms. In light of this new evidence, CDC recommends wearing cloth face coverings in public settings where other social distancing measures are difficult to maintain (e.g., grocery stores and pharmacies)especially in areas of significant community-based transmission.

It is critical to emphasize that maintaining 6-feet social distancing remains important to slowing the spread of the virus. CDC is additionally advising the use of simple cloth face coverings to slow the spread of the virus and help people who may have the virus and do not know it from transmitting it to others. Cloth face coverings fashioned from household items or made at home from common materials at low cost can be used as an additional, voluntary public health measure.

The cloth face coverings recommended are not surgical masks or N-95 respirators. Those are critical supplies that must continue to be reserved for healthcare workers and other medical first responders, as recommended by current CDC guidance.
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Finally and thankfully San Diego, CA is now mandating all workers to wear masks and anyone who has to go out they recommend for them to do so too. Not the N95 masks.

https://www.nbcsandiego.com/news/lo...an-diego-countys-public-health-order/2298442/

The order will make it mandatory for businesses that interact with the public to use cloth face coverings for their employees starting Saturday; that includes grocery stores, pharmacy, gas stations and restaurants, according to Supervisor Nathan Fletcher.
...

The general public will not be required to wear facial coverings but will be urged to do so when out in public for essential activities, according to the new order.

Medical-grade masks should not be used but homemade masks, bandanas, scarves and neck gaiters are acceptable since the items can be washed and reused.

The changes came after county leaders called April a critical month for the San Diego region in the fight against COVID-19.
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Hip said:
Glad to see the CDC are more on the ball with this.

The UK are still saying that there is no need for the general public to wear masks or to place a cloth covering over their face.
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I think they just added it today.

Hopefully with others sharing the CDC's and sharing it with their gov't officials they will get going with it and not wait any longer. In the meantime, we all will do what we can to get it going and make it safer.

Thank you for starting this thread @Hip.

Please keep taking good care as you can everyone.
 
One general observation about how the world is dealing with this coronavirus pandemic:

Obviously this is a medical issue, so the medical profession are the main players. However, by nature the medical profession is conservative and evidence-based, which is good in general, but may not be particularly helpful characteristics in a novel situation like this.

Analogy to wartime has been made with coronavirus. But in World War Two, people tried all sorts of creative ideas to defeat the enemy. They did not go around saying: "there's no empirical evidence to suggest Barnes Wallis's bouncing bomb will bring down those dams"; they just went ahead and tried out ideas that had a reasonable chance of working.

So I think we need to apply the same creative, experimental thinking in our efforts to defeat this pandemic. There was plenty of indirect evidence suggesting that masks or face coverings for the populace would be useful, and it costs nothing to ask the public to cover their faces with cloth. But it's taken months for the US to go with this idea, and the UK have still not adopted it.
 
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Hip said:
However, by nature the medical profession is conservative and evidence-based, which is good in general, but may not be particularly helpful characteristics in a novel situation like this.
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I actually think this is the opposite of the case. Evidence based medicine was introduced by the medical profession to try to clean up its act because by nature doctors not only 'just went ahead and tried out ideas that had a reasonable chance of working' they were constantly going ahead with ideas that had been shown to be useless but made doctors rich - like tonsillectomy.

If I had not gone ahead and tried rituximab for RA it would not be licensed. For thousands of years the medical profession consisted entirely of people trying things in the hope they might work.

The actual restriction of medical activity came with a political desire to save money from either governments or insurance companies. They had to fight the medical profession hard to restrict 'clinical freedom'.

The decision not to wear masks because there was little evidence they worked was almost certainly a political one driven by shortages. Moreover, evidence based medicine implies that you weigh up the most likely balance of benefit and risk from what limited evidence you have. Since wearing masks does not seem to have a risk evidence based medicine would say wear one, if only because it is common sense that it might stop sputtering virus on other people.
 
Hip said:
However, this might be misleading information, as the study I mentioned in the first post found that there was virtually no difference between surgical masks and respirators in their ability to prevent medical staff from contracting influenzavirus in a hospital looking after influenza patients.

That study demonstrates cheap surgical masks are just as good as respirators in protecting the wearer from a contagious viral infection.
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That study is for influenza, so you can't fully generalise the findings for SARS-Cov-2 which is more infectious.

If you had eye protection as well, and manage to handle the eye protection, mask and clean your face without further contamination, then it could help. But this is a far cry from the masks and handling methods that the general public is using.

Using such a mask incorrectly could actually increase your risk. Proper handling discussed here:
https://www.youtube.com/channel/UCIl-sKJCHJALZyeoewSI45g
 
I wonder how long the virus can survive on an N95 mask. It seems like you could sequester the masks in a circular chain for that period of time and then use them again once their "quarantine" period was up. I believe the article above on machine sterilization says that the masks themselves can be reused up to five times.

I can't find anything on the length of the virus' survival on an N95 mask. On other surfaces, though, it's a few days at most.

No doubt I'm overlooking something basic here.
 
Seems like a pretty convincing argument for masks:

https://www.theguardian.com/comment...sk-may-be-our-best-weapon-to-stop-coronavirus

Guardian said:
Every country with enforced mask usage shows dramatically lower death rates compared with countries not using masks widely.

We can also see dramatic results when a country changes its policy on masks. Masks were hard to come by in South Korea until late February. Then the government stepped in and ensured a supply for every person in the country. Up until then, South Korea showed a similar-shaped exponential trajectory to Italy. After that point the exponential growth slowed, and today the number of active cases is decreasing. There is no economic lockdown there.

[...] If we can’t rely on our governments to take this step, then we will have to take things into our own hands. We must rely on grassroots community efforts to get up to that magic 80% compliance number. We know this is possible, because the Czech Republic did it last month. In that country, a brilliantly effective social media and influencer campaign saw the country go from 0% mask use to nearly 100% mask use in three days. Then the government followed and made it the law.

Now it’s time for the rest of us to make this happen in our own communities.
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I've been talking to friends lately about how it would be good if everyone wore masks not for self-protection but to protect others but weirdly, they can't seem to hear it, even the health professionals - they still think in terms of self-protection and so think it would be a waste of time. That Guardian article has convinced them, though!
 
Hip said:
One general observation about how the world is dealing with this coronavirus pandemic:

Obviously this is a medical issue, so the medical profession are the main players. However, by nature the medical profession is conservative and evidence-based, which is good in general, but may not be particularly helpful characteristics in a novel situation like this.

Analogy to wartime has been made with coronavirus. But in World War Two, people tried all sorts of creative ideas to defeat the enemy. They did not go around saying: "there's no empirical evidence to suggest Barnes Wallis's bouncing bomb will bring down those dams"; they just went ahead and tried out ideas that had a reasonable chance of working.

So I think we need to apply the same creative, experimental thinking in our efforts to defeat this pandemic. There was plenty of indirect evidence suggesting that masks or face coverings for the populace would be useful, and it costs nothing to ask the public to cover their faces with cloth. But it's taken months for the US to go with this idea, and the UK have still not adopted it.
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From a scientific/medical viewpoint, I wonder if there is anything novel here (apart from the fact it's gone Global)? It's a virus and the WHO advice has been clear from the start --- you can't fight what you can't see --- test, trace contacts, isolate +ve's, reduce transmission. Look at the numbers of people who died in Lombardy (500/million) versus Veneto (57/million)*; Veneto tested people in their homes and quarantined them there e.g. delivering food and medicines. The WHO has been clear that there are different strategies that have worked in different societies; however, they all involve the same fundamentals - test, trace contacts, isolate +ve's, reduce transmission.

In terms of the role of the medical profession i.e. in advising the Government; the clue is that they advise, Ministers/Prime Minister decide. The obvious question is why didn't they follow Veneto - test, trace contacts, isolate +ve's, reduce transmission? OK, they couldn't deliver the first thing "testing"! You need PCR/antigen testing to identify those who are infected/infectious; so that you can isolate them and reduce transmission. So the Government's abandonment of the test --- strategy is presumably due to the fact that it couldn't deliver and it didn't want to explain why**!

As for a military analogy; the population are hiding in bunkers. As for ammunition, the Government hasn't announced large scale testing to identify those infected/infectious; it's announced testing for those who have been infected/are not infectious (antibody/serology/blood tests). So they haven't offered anything to turn the battle (PCR/antigen testing)--- your stuck in your bunker hoping you/yours survive -- we all are!

Your reference to the bouncing bomb (WW2). I thought this was actually an example of something that soaked up a lot of resources (including the lives of aircrew) and achieved nothing militarily, but has rather brilliantly been re-framed as a success. Is that the analogy you are trying to draw i.e. a strategy which resulted in a greater loss of life/economic downturn, re-branded as success -- you may be on to something!

When you take on a role in Government policy you are reminded that your responsibilities include --- presenting Government policy in the best possible light. So view anything from Government with that in mind --- I think we are indebted to those who are knowledgeable and are not constrained by that responsibility --- Anthony Costello @Jonathan Edwards

I've followed @Keela Too example i.e. a home made mask. Without being gender stereotypical (male) I just cut up a hoover bag and stuff bits in a balaclava (as a filter). The filters have just been sterilised, in water with detergent (64+ degrees centigrade ---possibly go for 74 next time), and are drying out for re-use.

A family member (female - gender stereotypical) has made one on a sewing machine --- probably in the faint hope I'll wear it!

@Jonathan Edwards interesting about the tonsillectomy; could you provide a link to a paper regarding the assessment of tonsillectomy? Any link between ME and tonsillectomy?

*https://hbr.org/2020/03/lessons-from-italys-response-to-coronavirus
**https://www.theguardian.com/comment...herd-immunity-community-surveillance-covid-19
haven't read the Guardian article yet.
 
Forbin said:
I wonder how long the virus can survive on an N95 mask. It seems like you could sequester the masks in a circular chain for that period of time and then use them again once their "quarantine" period was up. I believe the article above on machine sterilization says that the masks themselves can be reused up to five times.

I can't find anything on the length of the virus' survival on an N95 mask. On other surfaces, though, it's a few days at most.

No doubt I'm overlooking something basic here.
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Ian Lipkin says that they are testing whether "56 degrees (centigrade) for 30 minutes"* would work for sterilising masks i.e. so that they can be re-used. However, I'm not sure how you could do this at home; possibly start 10 degrees higher in a thermos and that way you'd maintain the (56 + degree) temperature for long enough. I've just been putting my hoover bag filters into water/detergent at a bit higher --- 65+ and I may go a bit higher still --- 74 (works for high risk foods like chicken). @Keela Too

@Snow Leopard Part of this is that masks may reduce the risk of you infecting someone else; I sure wish those in my supermarket used them (during my 1/5 day visits!).

*time approx 51.30 minutes in the interview http://www.microbe.tv/twiv/twiv-special-lipkin/
 
For items that can’t be washed would a conventional oven do? 60’C isn’t generally a temp that burns things. I actually put fabric I’d received from an online supplier into the oven for about an hour at 75’C. I was just guessing of course, but looks like I was on the right side of effectiveness!
 
Jonathan Edwards said:
I actually think this is the opposite of the case. Evidence based medicine was introduced by the medical profession to try to clean up its act because by nature doctors not only 'just went ahead and tried out ideas that had a reasonable chance of working' they were constantly going ahead with ideas that had been shown to be useless but made doctors rich - like tonsillectomy.
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Appreciate that point, and certainly doctors may have been more experimental in the past. But in countries like the UK, where evidence-based medicine has been practiced for many decades now, so medics can only do what NICE and the NHS stipulate they are allow to do, perhaps this not the right culture and environment to stimulate creative experimental thought?

So maybe this culture stultifies medical creativity a bit, or puts the more creative types off becoming a doctor? I am not berating evidence-based medicine though, just commenting on it.

Definitely not good, though, to have an idea but not then test it out empirically. Nothing worse than someone who assumes their theoretical model or pet idea must be true, without checking if it really works empirically.
 
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