We need #masks4all

00:00:00.000 | Hello there, and thank you for joining us.

00:00:04.840 | My name is Jeremy Howard.

00:00:06.720 | I am the co-founder of FastAI, and this is the other co-founder of FastAI, Rachel Thomas.

00:00:13.440 | Hi, I'm Rachel Thomas.

00:00:15.680 | My background is I have a PhD in math, and I previously worked as a software engineer

00:00:19.520 | and data scientist.

00:00:21.440 | More recently, I'm the founding director of the Center for Applied Data Ethics at the

00:00:25.520 | University of San Francisco, and as Jeremy said I'm also the co-founder of FastAI.

00:00:31.400 | So Rachel is a mathematician / data scientist / software engineer turned data ethicist.

00:00:38.760 | I am the opposite.

00:00:39.960 | My major was actually in ethics, and nowadays I'm a professional data scientist.

00:00:47.400 | So we both together are super interested in combining data and ethics and policy and society.

00:00:56.720 | And we found ourselves in a funny position last week where we were starting recording

00:01:02.680 | our big annual course, which hundreds of thousands of people a year watch right at the time that

00:01:09.480 | the COVID-19 thing was exploding.

00:01:13.240 | And so we did some work looking at COVID-19 in terms of from what the data looks like.

00:01:21.720 | Much to our surprise, the report we wrote has been read by well over half a million

00:01:26.360 | people.

00:01:27.360 | The video we created as part of this course is being watched by thousands of people.

00:01:32.480 | And there's a request for us to do more of that.

00:01:34.360 | So here we are doing more of that.

00:01:37.040 | And today we're going to tackle a topic which I think is likely to be the most important

00:01:42.600 | topic we've ever tackled.

00:01:44.840 | So let's jump in.

00:01:49.840 | So this is I think the hardest situation I've ever been in trying to teach.

00:01:55.720 | And the reason why is because I am in the United States of America.

00:02:00.880 | And here in the US over the last 24 hours, there has been this extraordinary new movement,

00:02:06.920 | which is basically to say, let's just let people die on the assumption that that's going

00:02:14.160 | to help the stock market.

00:02:16.120 | And so if I seem a little less than Jovial today, it's because I am less than Jovial

00:02:23.160 | today.

00:02:25.080 | So I'm not going to be talking about that in particular.

00:02:28.400 | Hopefully it's actually pretty obvious that well, I mean, economists are already saying

00:02:34.080 | it would cost about $5 trillion before we even start taking account of the lost productivity

00:02:38.520 | due to the fact that people would not be going to work anymore when all of their friends

00:02:41.520 | and family are dying around them.

00:02:43.400 | So economically not a great idea and you know, societally, maybe one of the most evil things

00:02:50.040 | I've ever heard in history.

00:02:53.280 | But we're going to not focus on that, we're going to focus on a potentially interesting

00:02:57.040 | part of a really important possible solution to the longer term.

00:03:02.400 | The first thing I wanted to mention is we've been talking a lot about the importance of

00:03:09.120 | stopping the spread and a key part of that has been locking things down as soon as possible.

00:03:15.080 | And interestingly, we're already seeing in the US the impact of that in the US, Kentucky

00:03:21.480 | and Tennessee right next to each other.

00:03:26.000 | They are testing at similar rates and so you would expect them to have a similar spread.

00:03:32.600 | Kentucky got in ahead of Tennessee when it came to doing a lockdown in terms of the,

00:03:39.320 | you know, they actually just declared a state of emergency back on March the 6th.

00:03:43.720 | And you can see already the difference between the number of cases in Tennessee, positive

00:03:48.640 | cases, positive tests versus the number of positive tests in Kentucky is an extraordinary

00:03:55.240 | big difference.

00:03:56.240 | So, so the stuff we are now seeing starting to happen around the Western world with these

00:04:00.480 | lockdowns again and again we're seeing the earlier the better.

00:04:06.240 | The orange bar here is the number of positive cases in Tennessee and the blue bar here is

00:04:13.200 | the number of positive cases in Kentucky, whereas the lighter blue and lighter orange

00:04:18.200 | is the number of tests that have been done.

00:04:23.960 | There's still people saying that maybe not that many people are actually dying and finding

00:04:28.440 | all kinds of obscure ways to murder the data to suggest that even Italy is actually not

00:04:35.040 | that bad.

00:04:36.040 | But the, you know, the fact is if you look for example in the region around Bergamo in

00:04:42.800 | Italy, the number of people who died last week was four times higher than the number

00:04:50.120 | of people that died a year earlier.

00:04:52.640 | So like regardless of how you think about what kind of testing is being done or you

00:04:58.000 | know what kind of post mortems are being done or whatever, there's four times more people

00:05:05.120 | dying you know of all causes in this region.

00:05:11.040 | This thing is killing people at an astonishing rate and it's not even close to peaking.

00:05:20.680 | So obviously we need these lockdowns but the question is what happens next.

00:05:26.240 | And we saw last week this tweet from the Surgeon General saying don't buy masks, they're not

00:05:34.640 | effective except for healthcare providers.

00:05:41.560 | And this has been a kind of pretty common refrain, it's certainly not only the US Surgeon

00:05:46.520 | General that's saying that and there certainly is a big issue.

00:05:52.920 | Doctors are saying there is not enough protective equipment including enough masks for hospitals.

00:06:01.320 | So PPE is referring to this protective equipment, masks, gowns, eye shields.

00:06:10.320 | There is a huge shortage.

00:06:12.840 | And so perhaps the reason that a lot of policy folks are saying masks are not useful is to

00:06:21.200 | stop people buying them, I mean this is what he's saying here don't buy masks in the hope

00:06:25.440 | that that will cause there to be more masks available for folks in hospitals.

00:06:34.240 | You know interestingly when you actually look at what hospitals are doing they're saying

00:06:39.280 | please, please donate us protective equipment.

00:06:43.320 | These are things we need, not just protective equipment but even testing equipment.

00:06:47.480 | But interestingly they're even saying handmade masks would be useful.

00:06:52.720 | So you know it's interesting to see what the actual hospitals are saying they want.

00:06:59.460 | And so when hospitals are saying we need masks and even handmade masks would be useful it

00:07:08.200 | starts to question this idea that like they're not useful for the public like why do hospitals

00:07:15.080 | want them if they're not useful to the public like how does this work.

00:07:20.680 | There's also some interesting empirical data very rough empirical data but if you look

00:07:27.920 | at all the countries which have flat curves they are all countries actually where mask

00:07:37.360 | wearing is extremely normal and not wearing a mask in places like public transport would

00:07:44.320 | be considered very anti-social.

00:07:48.220 | So there's this kind of country level data that suggests that well something's going

00:07:56.020 | on in these countries and is masks part of that.

00:08:01.600 | Taiwan does not appear on this at all because this they basically didn't have enough cases

00:08:12.040 | to appear on this graph at the time that this tweet came out.

00:08:18.360 | They only have 153 cases and two deaths in the whole of Taiwan even though they're right

00:08:23.200 | next to China where this thing blasted off.

00:08:28.240 | So what happened in China in Taiwan they are making 10 million masks per day.

00:08:34.840 | Now I thought that sounded crazy unlikely but actually this is the leader of Taiwan

00:08:41.360 | and here she is saying yes Taiwan is now making 10 million masks per day and they're a small

00:08:49.760 | country.

00:08:50.760 | I think they're like 30 million people or if you like a small region depending on your

00:08:54.200 | politics around this.

00:08:58.980 | So that kind of got me interested like thinking well if masks are important and a small country

00:09:06.280 | like this can create so many you know what does that mean for a country like the US is

00:09:13.200 | that something we should be doing.

00:09:16.000 | And so I started doing some research and I saw for example University of Michigan study

00:09:21.280 | on pandemic flu not on COVID-19 but this similarities and they found that combining hand washing

00:09:31.840 | and using masks makes a huge difference to the spread of pandemic flu 75% reduction.

00:09:42.800 | Now 75% reduction would be the difference between a pandemic and something that would

00:09:47.440 | just die out and fizzle away.

00:09:50.020 | So this is again indicative it's not proof.

00:09:54.920 | So I started digging in some more and I asked the wider community to help and we now have

00:10:01.760 | a list of 30 papers or nearly 30 maybe it's 28 papers that have actually studied the question

00:10:11.080 | of the efficacy of masks as a way to stop spread and transmission from many different

00:10:17.360 | angles and many different types of masks and all of the research I've seen points to any

00:10:26.600 | kind of mask as being helpful to significantly stopping transmission.

00:10:35.640 | So this has been quite a learning journey for me and so I've really focused on what

00:10:41.160 | is the data say and just looking at primary research papers not at government recommendations

00:10:47.160 | not at blogs but at actual science and we'll provide the link to these papers with the

00:10:56.160 | video.

00:10:57.160 | One of the most interesting things I discovered is in the Czech Republic which has a really

00:11:02.800 | fantastic healthcare system and is doing a lot of testing they actually made mask compulsory

00:11:09.200 | for the whole country since March 18th if you want to go anywhere you have to wear a

00:11:13.200 | mask outside the house and they have these little illustrations the Czech here means

00:11:21.660 | your mask protects me my mask protects you and they're really focusing on the social

00:11:27.320 | side that if I have a mask on I and I might be sick and I don't know about it I am actually

00:11:34.000 | doing a pro social thing by helping you to not get sick.

00:11:39.200 | In the whole country there's only been two deaths and look at how the you know we're

00:11:43.920 | not seeing the exponential growth in new cases it's actually flattened out.

00:11:51.640 | So this is a super interesting situation so I started wondering like well how did that

00:11:55.680 | happen how did this country like the like very unusual in Europe to see mask wearing

00:12:03.440 | so how did this happen.

00:12:06.160 | And there is this fantastic story about what happened.

00:12:10.320 | You can find it at tiny.cc/masksrule strongly recommend reading it.

00:12:18.080 | But basically what it says in fact let me jump to it now.

00:12:26.120 | What it says is this guy Peter Ludwig who is a kind of a social media influencer who

00:12:35.280 | focuses in science communication made a video about the importance of wearing masks and

00:12:43.960 | that kind of kicked off this huge community reaction.

00:12:53.200 | It's an amazing story and this is this is the video this is this is Peter and I after

00:13:00.880 | really digging into the data and the virology and the science of this I am pretty convinced

00:13:10.120 | that everybody wearing masks could be a key or probably is a key part of the solution

00:13:16.320 | to stopping the lockdown eventually getting the economy back on track restoring normal

00:13:22.400 | normalcy to society and reducing the spread.

00:13:27.560 | I am not as good a science communicator as Peter is.

00:13:31.560 | So what I'm going to do is I'm just going to tell you what he said with his pictures.

00:13:36.240 | OK so I get no credit for this.

00:13:39.080 | I'm just repeating what he said because maybe you don't speak Czech.

00:13:44.040 | So Peter started out his fantastic video by pointing out Mongolia.

00:13:50.360 | Now Mongolia is right on the border of China.

00:13:52.840 | So lots of people moving backwards and forwards right and somehow at the time that he did

00:13:57.920 | this the 14th of March they had only one case.

00:14:01.760 | Today it's gone up to four cases.

00:14:03.640 | It actually turned out that one case checked themselves out of hospital and against the

00:14:09.880 | law went and hung out with 200 people over the next few days which is a terrible terrible

00:14:16.920 | idea.

00:14:17.920 | But how come Mongolia had only one case.

00:14:22.040 | And so Peter said he noticed that something striking about Mongolia was they had a policy

00:14:28.120 | that you have to wear masks since January which is pretty extraordinary.

00:14:35.360 | So Peter went on to describe and I'm using some of my own slides now.

00:14:38.840 | His slides are much more his presentation is much nicer than mine but I wanted to show

00:14:45.160 | you some additional information here.

00:14:47.160 | So he described how there are different kinds of masks there are what are called respirators

00:14:51.840 | the most common type being the N95 to just a rating and they're they're full seal hospital

00:14:58.800 | grade things right versus surgical masks which are these just loose fitting pieces of cloth.

00:15:10.480 | The key thing here is that these these different pieces of protective equipment protect you

00:15:15.760 | from from different things but what's interesting is as Peter mentioned there there is research

00:15:27.520 | that shows that even the basic loose fitting pieces of cloth actually works super well

00:15:35.360 | against a wide variety of viruses.

00:15:39.400 | So this is actually the research that he's pointing out and this comes from smart air

00:15:43.440 | filters dot com but the actual data comes from this report Davis Adele they've just

00:15:50.840 | made it into a nice picture and what they found is that against 0.02 micron particles

00:15:56.700 | surgical masks are super effective vacuum cleaner but bags are super effective dish

00:16:01.080 | towels are super effective cotton t-shirts are super effective and then and actually

00:16:05.840 | in this study they had two different sized particles they also looked at point one micron

00:16:09.620 | particles I think it was point one and they found the same things were even more effective

00:16:15.000 | because 0.02 is particularly small they also looked at kind of doubling them up and they

00:16:21.240 | also looked at how well can you breathe through these different materials and they actually

00:16:26.600 | came up with some suggestions around things that are easy to breathe through so in this

00:16:31.040 | case two t-shirts easy to breathe through and end up being pretty effective so anyway

00:16:41.360 | you can check out this fantastic article or the original paper for yourself but basically

00:16:46.560 | the story they found in in this research and a lot of other research I've looked at is

00:16:53.640 | for stopping the spread of viruses you don't need and 95 respirator masks at all you know

00:17:03.200 | I mean they're great but lots of other things work great as well so what's going on here

00:17:12.880 | how does this work because covered 19 is a 120 nanometer sized virus so Peter points

00:17:21.080 | out that like oh how can these you know simple pieces of cloth protect from that because

00:17:27.260 | they don't they have bigger holes in 120 nanometers the point Peter made though and is described

00:17:33.880 | again and again in all the research I've looked at is that covered 19 is spread through droplets

00:17:42.040 | in other words you cough and it goes into your face right and specifically it goes into

00:17:49.200 | your eyes or it goes into your nose or goes into your mouth also talking sometimes I've

00:17:54.920 | noticed when I talk little bits of spit fly out I'm sure we're all like that so these

00:18:01.040 | are droplets and the droplets is what the mask catches so there are three categories

00:18:09.400 | of transmission described by virologists says contact transmission droplet transmission

00:18:15.360 | airborne transmission so contact is when you actually touch someone or something with the

00:18:20.760 | virus and this is a big issue if you touch you know we talked last week about sanitation

00:18:25.240 | if you touch a surface which somebody who is infected is touched also and then you touch

00:18:30.600 | your face that can get you sick what we're talking about for masks though is the coughing

00:18:38.400 | and talking which seems to be such a common vector for spread because that's actually

00:18:45.640 | how on the whole this particular virus is kind of expelled airborne is a nightmare airborne

00:18:54.080 | is when things they say it's a aerosol eyes that here into it they turn into an aerosol

00:18:58.120 | they float in the air and tiny tiny tiny like a sub remember the was point five micron droplets

00:19:05.240 | for ages that can actually happen in a hospital there are certain procedures in the hospital

00:19:11.300 | which cause the droplets to aerosol eyes and and the kinds of masks we're talking about

00:19:18.880 | the basic masks don't really help there so in a hospital setting where there's potential

00:19:23.600 | aerosolization you need the good masks so actually Oxford University just published

00:19:29.580 | today a new report about this where they described how basic masks are fine except for if you're

00:19:39.240 | in a hospital around an aerosol generating procedure or AGP and this is a list of AGPs

00:19:47.160 | so you're probably not doing these things at home right so so you're fine to use whatever

00:19:54.240 | couple of layers of t-shirt right in the hospital even unless this is what the University of

00:20:01.240 | Oxford is saying from their research it's this is with COVID-19 research this is not

00:20:05.640 | just any old research so like basic masks homemade masks this is why the University

00:20:13.280 | we looked at earlier is asking for homemade masks even because they they do really help

00:20:20.560 | so there's been a lot of research already empirical research showing that these basic

00:20:25.480 | marks acts basic masks actually help in practice for example for SARS so this is from slate

00:20:31.040 | star codex.com a summary of some research they have a link to a paper about SARS which

00:20:38.240 | looked at how folks that were wearing even surgical masks got no infections at all.

00:20:50.720 | This is the Oxford study that I mentioned and so their conclusion again standard surgical

00:20:56.260 | masks can be used for most community-level clinical interactions let alone at home right

00:21:01.520 | so they were explicitly looking at home but we've seen from the other research that basic

00:21:07.120 | materials are just as good as surgical masks or very close to.

00:21:12.680 | The research empirical research has also found that basic masks do help in practice empirically

00:21:17.880 | in practice they do help in non-healthcare settings again not COVID-19 but swine flu

00:21:25.920 | when they looked at the result of a flight in which there were folks with swine flu on

00:21:30.720 | that flight those people that wore a basic mask were 0% that wore masks got sick compared

00:21:40.520 | to 35% of non-wearers got sick so there are huge differences when you use even basic masks.

00:21:51.120 | This is totally in line with what virologists say so this virologist says COVID exposure

00:21:57.240 | dose matters this is really important kind of when you're thinking about the science

00:22:01.320 | here masks can help anyone because they reduce the amount of virus released or taken in and

00:22:09.680 | the immune system wants a low dose so if you keep the dose low and the virus has to divide

00:22:16.880 | many times to get to high levels and then the immune system's got lots of time to kick

00:22:20.960 | in right so this is like kind of counterintuitive but this is actually what the data is now

00:22:25.760 | showing us and the science is now showing us is that the transmission of this virus seems

00:22:32.360 | to occur primarily through sustained exposure right so in Hong Kong and Singapore they define

00:22:39.880 | that as less than six feet away from somebody for at least 15 minutes in Hong Kong or 30

00:22:47.400 | minutes in Singapore right so this is super important for like understanding how this

00:22:55.160 | virus works it's not about just passing somebody in the street unless they cough on you but

00:23:01.360 | actually being around somebody for an extended period of time and close to them so a key

00:23:12.120 | point which we absolutely know now we've got plenty of data to show this now is that many

00:23:18.960 | people are infectious before they have symptoms so it's not okay just to wait until you're

00:23:24.360 | coughing before you start putting a mask on something like 50% of people with the virus

00:23:29.960 | are asymptomatic and they are spreading it even then so this is a key reason why you

00:23:39.040 | have to get the mask on early so these little pictures here is Peter is describing how when

00:23:45.000 | you wear a mask you stop other people from infecting you but you might be infected with

00:23:50.040 | have no idea you might never get symptoms right but you could be spreading it to your

00:23:54.840 | friends your family your community your co-workers without knowing it so you need to wear a mask

00:24:01.920 | for that reason as well so he describes this as a selfless motivation and this has been

00:24:07.480 | a key part of the messaging in the Czech Republic is this idea that is this is such a pro-social

00:24:13.160 | behavior to wear a mask because you are protecting the people in your community the people in

00:24:19.680 | your workplace so if we look at it we saw that graph earlier that showed there's quite

00:24:26.120 | a few countries now that are controlling this without a lockdown like Korea and in every

00:24:36.200 | country that that has controlled it without a lockdown or isn't in a lockdown anymore I

00:24:41.760 | should say they're doing four things they're doing rigorous testing they're doing rigorous

00:24:48.680 | contact tracing so if you're tested positive who's everybody you've you've been near they

00:24:55.360 | quarantine anybody who's found positive and everybody's wearing masks on you know on public

00:25:03.240 | transport at work you know anywhere they're around other people outside of their family

00:25:10.640 | so like from a data science point of view this is you know we don't need proof right

00:25:18.400 | none of these are economy destroying levels of cost right masks I mean it can make our

00:25:25.600 | own masks for like 10 cents so you know these are things that allow us to get the economy

00:25:32.380 | going again and avoid people dying so we save lives and potentially trillions of dollars

00:25:39.120 | and it's not this is not like some crazy idea that might just work this is something that

00:25:44.880 | lots of countries have done and it's already worked so it's like why isn't everybody doing

00:25:50.840 | this we need the lockdowns to order get to the point because so many countries like the

00:25:55.920 | US and the UK are way too late but you know in a few weeks or a few months once we're

00:26:02.440 | past the apex this is what we need to be doing and it's going to be super hard to do the

00:26:07.320 | masks bit because we're you know our governments have been stigmatizing this you know they're

00:26:11.840 | saying you don't need them if you wear a mask you're taking it away from from hospitals

00:26:18.280 | so there are now all these Asian countries that acted quickly to contain the virus and

00:26:24.560 | you actually look at like just the traffic on the streets they're kind of back to about

00:26:29.280 | normal so there's lots of data you can look at in this case this is Tom Tom traffic congestion

00:26:35.300 | right and it's just fascinating to look at these countries where the last seven days

00:26:43.680 | versus historical average this is from the Financial Times I believe sorry for accidentally

00:26:49.800 | cutting off the citation which I tried to keep you can see how there are countries that

00:26:57.040 | are nearly back to normal people are moving around again so Peter used you know used all

00:27:05.920 | that to try to get rid of the first idea which is we don't need masks we do need masks so

00:27:12.200 | that was his cross that off so the second argument he dealt with is there's no point

00:27:17.680 | saying you need masks because there are no masks so his point was well make them go and

00:27:26.440 | make masks and so here are pictures of people in the Czech Republic after this video came

00:27:30.640 | out making masks and hanging them up on mask trees for anybody to come and pick up that

00:27:36.680 | needs one and one of the things you notice here is the masks don't look professional

00:27:41.520 | and I think this is really important right because if you have a polka dot mask nobody's

00:27:47.640 | going to come up to you and say you're stealing you know professional hospital grade masks

00:27:52.300 | you know that they're they're cute and so part of the the Czech community reaction was

00:27:57.440 | to have like you know humor and you know just make it as fine as possible get everybody

00:28:07.280 | involved so even kids have their koala I don't know why there's koalas in Czech Republic

00:28:13.920 | I guess it's just are there on a visit who has its own mask there are all kinds of interesting

00:28:24.400 | things you could use for these masks so one chap pointed out that 3m has a household filter

00:28:31.200 | which costs 22 bucks and gives you enough for 60 masks and it is actually officially

00:28:35.480 | virus rated so you know if you want to go fancy you can spend 30 cents and cut those

00:28:42.680 | up as we've already noted things like cotton should be just fine too but yeah string staples

00:28:48.840 | and hot glue $22 worth of this stuff maybe a bit of cloth on each side to make it more

00:28:54.680 | comfortable so the the call to action that Peter made was basically he said I want everybody

00:29:02.520 | in the Czech Republic to wear a mask everybody 100% of the country which I mean that sounds

00:29:09.040 | crazy to me that that could be possible because at the time this was something that had a

00:29:12.840 | social stigma around it so he pointed out something really interesting which is that

00:29:17.440 | this would not be if this was successful it would not be the first time that something

00:29:20.760 | with a social stigma turned around just like in most western countries when I remember

00:29:28.600 | when I was growing up dogs would poop on the sidewalk and you would leave it there and

00:29:33.000 | he pointed out that we managed to change the social expectation that if a dog poops you

00:29:38.160 | pick it up and before that changed no question people would have been like oh my gosh you're

00:29:44.480 | picking up poop that's gross whereas now it's like excuse me you seem to have left your

00:29:51.280 | dogs fecal matter on the sidewalk please pick it up thank you very much so you know these

00:29:56.560 | things can change social expectations can change and so he his his hope was that if

00:30:03.480 | you see somebody without a mask you know people will stare at them and think who is this anti-social

00:30:09.440 | person so he made three particular asks he said share this video take a selfie wearing

00:30:19.860 | a mask and use the hashtag masks for all well actually the Czech version but let's pick

00:30:26.360 | the English version and influence influences should set a good example for their followers

00:30:32.240 | and so I think it'd be super cool if like you know celebrities started rocking their

00:30:38.780 | own homemade colorful masks maybe pictures of them making them themselves you know I

00:30:44.000 | mean I think that would be super important and you know the point is that this is little

00:30:55.200 | word cloud of like the most important values to folks in the Czech Republic and the biggest

00:30:59.440 | one was kindness and so he is saying like this is this is the most kind thing you can

00:31:04.960 | do is to have a little bit of inconvenience yourself in order to protect those around

00:31:10.960 | you oh my god it was successful so today when politicians appear in public they're all rocking

00:31:19.940 | masks people are putting mask pictures on the public transport on the statues it's it's

00:31:27.480 | extraordinary so there's a lot of recommendations out there for face masks Michael in who is

00:31:38.400 | a biochem researcher has lots of great information that we can share similar kind of stuff what

00:31:48.000 | we've described about but some some more links actually a article that just came out today

00:31:58.120 | we might need to update this is that actually this looks correct so he's actually already

00:32:03.280 | got a new thing if you put a mask in the oven at 160 Fahrenheit 70 centigrade for 30 minutes

00:32:12.480 | it sterilizes it and you can use it again as much as you like no alcohol so there's

00:32:18.300 | actually a new Harvard study I just saw today which actually has has has shown this interestingly

00:32:26.120 | you can see this is coming from a ways in QQ you know Chinese sites a lot of the best

00:32:31.400 | information we have is coming from Chinese sites because they're the ones with the you

00:32:35.440 | know months months more experience of this so a really interesting thing that appears

00:32:43.080 | all the time in like the training that doctors talk about for mask fitting is if you want

00:32:49.860 | to know if your masks working pretty well go somewhere like get something smelly like

00:32:55.840 | some sugary water or some smoke or something and see if you can still smell it with your

00:33:01.560 | mask on and if you if it's if you can smell it a lot less then you're blocking the particles

00:33:08.240 | so that's kind of the rule of thumb that you keep I keep seeing people talking about okay

00:33:16.120 | so that is what I wanted to say about masks I guess you know I I'm not a big YouTube influencer

00:33:26.120 | thought leader whatever I'm just a data scientist but I guess my job is to look at data and

00:33:31.400 | try to figure out what it says and the data is super super clear on this it's not like

00:33:39.840 | there's no 100% perfect proof randomized controlled trial for this exact illness disease such

00:33:46.520 | a thing would be impossible because it hasn't really been around long enough you can't really

00:33:50.440 | do a randomized controlled trial where you say hey you're not allowed to use a mask and

00:33:54.560 | you are but from a kind of a Bayesian prior perspective the evidence is so incredibly

00:34:03.800 | strong that this is a good idea the cost is so low the upside is so huge in terms of lives

00:34:10.760 | saved and the economy being able to get back up and running again it seems like madness

00:34:17.840 | to me not to do this so I will repeat Peters cold arms here and say let's make this happen

00:34:25.920 | and particularly you know let's see influences come out wearing masks start start making

00:34:32.840 | masks we're going to have links with this video to how to make them at home it's very

00:34:38.360 | cheap it's very easy and let's hope that we can make happen in the US and the UK and other

00:34:46.520 | countries what the what the Czech folks have done so incredibly well

00:34:51.960 | [BLANK_AUDIO]

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