Airborne Transmission of COVID-19, Interview with Professor Morawska https://www.youtube.com/watch?v=wdE3NNPeIWI 00:03 well good day my name is brad 00:05 prizant i am the current vice president 00:07 of practice for izzy act the 00:09 international society of indoor air 00:10 quality and climate 00:12 with me today is professor olivia 00:14 marowska director of the international 00:16 laboratory for air quality and health at 00:19 queensland university of technology in 00:21 brisbane australia 00:23 dr marowska and 239 colleagues 00:26 many of whom are members of izzyak's 00:28 academy were recently successful in 00:31 persuading the who 00:32 to acknowledge the evidence base 00:35 supporting aerosol transmission 00:37 of sars cov2 after publication of hers 00:40 and donald milton's manuscript 00:42 it is time to address airborne 00:44 transmission of cobit 19. 00:47 most dizziac members are familiar with 00:49 the argument for air assault 00:50 transmission having heard your lydia's 00:53 and others 00:53 presentations at izzyak's indoor air 00:56 conferences over the last 10 years 00:59 or having read relevant articles in our 01:01 journal indoor air 01:02 so i'll be asking you a few questions 01:05 professor assuming some basic 01:07 familiarity with these issues 01:09 thank you for joining me professor 01:11 marowska first 01:13 given what we know about aerosol 01:15 transmission can you describe what some 01:17 of the greatest uncertainties are 01:19 within this framework and where we might 01:22 see additional supporting evidence in 01:23 the short term 01:26 it's a great honor to present this to 01:28 easier 01:30 there were a lot of questions regarding 01:32 infection transmission before this 01:34 pandemic questions to not many people 01:37 paid 01:37 much attention as in general uh an 01:40 infection transmission whether airborne 01:43 or 01:44 as such within the community wasn't 01:46 something discussed 01:47 at any great deal this situation now 01:51 generated lots of questions many many 01:53 questions 01:55 most of them are reasonably 01:58 um well i wouldn't like to say 02:01 small questions or undermine them but 02:04 questions adding to building the 02:06 whole jigsaw puzzle in terms of 02:08 infection spread 02:09 or the specific virus but if i were 02:12 to describe 02:15 what are the biggest questions being 02:18 asked 02:19 i again wouldn't like to use the word 02:21 uncertainties 02:22 there are is airborne transmission 02:24 occurring 02:26 and on population scale what's the 02:29 contribution of 02:30 airborne transmission to the total 02:32 infection spread 02:34 so i'll first address the one the first 02:36 one is airborne transmission occurring 02:39 well there is an overwhelming body of 02:42 evidence demonstrating from different 02:44 scientific 02:45 angles that airborne transmission occurs 02:49 this is a body of evidence generated not 02:51 just now during the pandemic but which 02:53 has been generated 02:54 over many years from the angles of 02:58 aerosol science which i represent when 03:01 we are talking about 03:02 aerosol exhaled from human exploratory 03:05 activities 03:06 the size distribution the dynamics of 03:09 this aerosol in the air from the biology 03:12 what such a result contains from 03:15 epidemiology as well as i said it's not 03:19 specifically of course to this virus in 03:21 relation to the studies 03:22 that have been done before but human 03:24 exploration for example and the process 03:26 of 03:27 resolution during human exploratory 03:30 activities is the same 03:31 whether we are infected with um 03:35 covet 19 or whether we are infected with 03:38 influenza so 03:42 another body of evidence which was 03:44 generated 03:46 now but also similarly during or after 03:50 sales one uh retrospective analysis 03:53 of the transmission during different 03:56 outbreaks so the outbreaks in 03:58 regards to the outbreak in the 04:00 principles hospital the outbreak on the 04:03 plane and so on 04:04 so as i said there's an overwhelming 04:06 evidence that 04:07 airborne transmission is happening 04:10 so however called for a perfect study 04:13 which would 04:15 absolutely prove without any doubt that 04:19 this specific virus impacted this 04:21 specific group of people 04:23 what i'm saying is is it likely that 04:26 a perfect study like this would ever be 04:29 conducted 04:30 well such study would involve a 04:33 prospectively 04:34 infecting healthy people under 04:37 controlled conditions 04:39 with the virus with this virus is there 04:42 any 04:43 um organization responsible for ethical 04:46 clearance 04:47 for epidemiological studies 04:52 would approve such study no such study 04:55 will not be conducted 04:57 so the if us if the question is about 05:00 this perfect study it won't be done but 05:02 otherwise 05:03 the evidence is absolutely overwhelming 05:06 about airborne transmission so this is 05:08 not 05:09 an uncertainty now the question on 05:12 to what extent uh the um airborne 05:15 transmission 05:16 contributes on population bears so 05:19 whether we are asking whether airborne 05:21 transmission contributes to 05:23 10 20 30 80 05:26 and this is something which uh on 05:29 population base will never be able to 05:32 answer because we'll never be able to 05:35 properly account 05:36 infections occurring due to different 05:38 transmission modes 05:40 well firstly because several 05:41 transmission modes can operate 05:43 at the same time and will never be 05:46 enough 05:46 data properly collected 05:50 to incre to include or exclude different 05:54 transmission 05:55 modes occurring in different situations 05:58 it is only outbreaks where we can trace 06:02 things what happened 06:03 or specific contacts in specific 06:06 situations 06:07 but we cannot tell this on population 06:10 base 06:10 and in particularly with the number of 06:13 people 06:14 fractional people who are asymptomatic 06:16 who are infected 06:17 but who don't show any symptoms they 06:19 don't know they're infected 06:21 we don't know they're infected so 06:24 therefore the answer to that question on 06:26 population base 06:27 how magic contributes will never be 06:30 available 06:31 however in in environments specific 06:34 environments where 06:36 outbreaks occurred and where they were 06:39 modeled for example in the during the 06:42 mount vernon 06:44 choir practice in washington state 06:47 where we were able to do retrospective 06:50 modeling of what happened 06:51 based on the data available about this 06:54 venue about the activities 06:56 about the precautions taken 06:59 by the members of the choir where we are 07:02 clearly pointed out that 07:04 uh the only basically logical 07:06 explanation is that this was 07:08 a airborne transmission our modeling 07:11 quite closely agrees what 07:13 actually happened so again the answer to 07:16 this question is that 07:17 this is not an uncertainty as such 07:20 it's something which we'll never know 07:22 but the fact 07:23 that we don't have specific value 07:26 whether it's as i said 30 40 07:28 60 on population base doesn't 07:32 mean that the evidence which we have is 07:35 inadequate or that there's an 07:37 uncertainty 07:39 now where i see however the biggest area 07:43 or where it needs to be done 07:45 and again i wouldn't call it a an 07:48 uncertainty 07:49 is how to link science of infection 07:52 spread 07:53 in particular infection risk assessment 07:55 with building 07:56 engineering to develop guidelines for 07:59 infection 08:00 and control in various settings 08:04 well someone may ask why do we need 08:08 such guidelines we have of course 08:11 guidelines 08:12 for ventilation for example 08:16 we've got in general guidance for 08:17 various aspects of engineering measures 08:20 um but none of this is looking 08:24 specifically from the angle of infection 08:27 control 08:28 none of this is considering the 08:31 virus and they've been updating very 08:34 good 08:35 modifications and recommendations done 08:38 by ashrae by riba 08:40 but again this is basically what we what 08:42 we what we know 08:44 how um improvement in ventilation 08:47 would uh improve certain aspects uh 08:50 related to the control of virus 08:54 but the type of guidelines required for 08:59 done for example being in place in 09:01 relation to the removal of 09:03 carbon dioxide which we exhale 09:06 is it relevant to control of the virus 09:10 well not quite we know exactly how much 09:14 carbon dioxide we exhaled but 09:17 the question about how much how much 09:20 virus is fed by infected person people 09:22 and in what situation 09:24 this is um this is a bigger question 09:27 question which can be quite 09:28 addressed in quantitative way but that's 09:30 what should be done 09:32 now in an example which i give in 09:35 relation to carbon dioxide 09:38 it's not that important in an 09:40 environment from which 09:41 carbon dioxide needs to be 09:44 removed which way the gas goes 09:48 let's say from a person who exhales it 09:51 to other people but in relation to 09:54 virus or infection control this is very 09:56 important 09:57 which way is going from the uh from the 10:00 infected person 10:02 so there are many aspects of this 10:05 um link which needs to be provided 10:08 between 10:09 the risk assessment quantitative risk 10:11 assessment to 10:12 this virus to any virus and to infection 10:16 uh to building engineering measures and 10:19 this needs to be done 10:20 in um such that the system can operate 10:24 in a flexible manner 10:25 for example we are saying that 10:27 recirculation is something to avoid 10:29 during a pandemic if that recirculation 10:32 may would not guarantee that the virus 10:35 is removed 10:36 but recirculation is important in terms 10:39 of energy conservation 10:41 so we don't want to give up energy 10:44 conservation 10:45 so but we should be able to switch from 10:47 one system to another 10:49 now i'm perhaps explaining this in a way 10:52 in a lay language i'm not a building 10:56 engineer i'm as you know i'm a 10:59 i may send this but um this is something 11:03 which from 11:03 a big picture we need to be done and 11:06 these are the 11:07 questions being asked so this is the new 11:09 knowledge which we need to generate but 11:11 not necessarily 11:12 uncertainty so this is my 11:16 answer to your first question 11:19 uh you you've answered my second 11:21 question to a certain extent 11:23 my second question was how do you see 11:26 the recognition of aerosol transmission 11:29 impacting public policy as well as 11:31 impacting a particular 11:33 building owner well 11:36 this is slightly different aspect and so 11:39 far there's been lots of 11:41 discussions speculations and hypotheses 11:43 whether airborne transmission 11:45 is important and if it is what to do 11:49 and this questions asked by individuals 11:52 questions asked by different 11:53 organizations different bodies 11:55 but there's been no basically 11:58 guidance from anywhere what to do and 12:02 some were saying well it's important we 12:03 should do something 12:04 but of course if an action is necessary 12:07 and this action 12:09 has to be driven by a 12:12 government body state national or 12:15 whatever 12:16 well such bodies are not necessarily 12:18 eager to jump in doing something 12:20 which they are not mandated not 12:24 requested to do 12:25 so it's been kind of uh talked about but 12:28 not much was happening 12:31 recognition of its significance of the 12:34 significance of airborne transmission 12:36 by w80 activates a whole chain 12:39 of actions than that that follows so 12:42 this is the most 12:43 significant aspect of this that and they 12:46 single 12:47 the stats change of activities so 12:50 national bodies state bodies which are 12:53 responsible for 12:56 control of 13:00 control of various aspects of public 13:03 health 13:05 then have a process of developing their 13:07 own guidelines and standards for 13:09 specific for the whole country for the 13:11 region and so on 13:12 and they have um very good 13:16 mechanisms for for doing this 13:20 that's that's that's new the guidelines 13:22 are developed and data developed and 13:24 the relevant bodies know how to do this 13:27 so then once such 13:28 uh documents are in place then once 13:32 promulgated 13:33 down the list then they will have to be 13:35 implemented by those who 13:37 design buildings operate the buildings 13:40 and in general who are responsible for 13:42 public health so then there are no 13:45 questions really 13:46 asked but there is a list of things 13:49 which are which need to be done and the 13:52 way 13:52 normally such process proceeds 13:56 so what i'm stressing is that the 13:58 recognition by the water of the 14:00 significance of the existence of 14:02 occurrence of airborne transmission is 14:05 the single most 14:06 important step to activate this chain 14:10 of actions that's this is response to my 14:14 second question 14:16 so let me ask you something of a 14:18 non-technical nature 14:19 is the mechanism of a large group of 14:21 scientists 14:22 writing an open letter something that 14:25 you think could be applied in other 14:26 contexts or could be directed 14:29 towards other governmental or 14:31 non-governmental institutions 14:32 or even possibly private companies in 14:35 your opinion 14:36 well for scientists writing an open 14:39 letter 14:39 is an act of desperation 14:44 normally scientists express the outcomes 14:46 of 14:47 our science of our scientific findings 14:50 in different ways 14:51 ways and in particular in peer-reviewed 14:53 publications 14:54 that's that's the platform where we say 14:56 what we've done and 14:58 to a platform problem for providing new 15:00 science 15:01 now then the organizations um in charge 15:04 of various aspects of operation of civil 15:08 societies 15:09 take this into account to develop 15:11 guidance and standards 15:14 for for the operation of different 15:15 elements of the societies 15:18 normally governments and other 15:19 organizations have mechanisms in place 15:22 how to be informed and act on emerging 15:26 science 15:27 so they would have their own units which 15:29 uh 15:30 acquire information about uh new science 15:35 they would formulate ad hoc bodies to 15:38 review the information or 15:40 standing bodies for for such and then 15:43 based on the recommendation from these 15:45 bodies then they decide what 15:46 what to do so this is a normal process 15:50 how science is uh 15:53 uptaken by the government and act by by 15:56 the government 15:57 now the problem however is if the 16:00 relevant bodies ignore 16:02 or dismiss the science and this has been 16:05 happening 16:06 so far in relation to infection 16:09 transmission 16:10 in general but specifically about 16:13 airborne transmission 16:14 in public settings of course there's a 16:17 different situation 16:18 in in healthcare and in particular in 16:21 in the units where infectious diseases 16:23 meet so 16:24 there's a very different situation but 16:26 i'm talking about public settings so we 16:28 are talking about the 16:29 offices schools libraries 16:33 shopping centers and so on that's that's 16:35 where the issue of 16:36 infection trans transmission has been 16:38 completely 16:39 ignored well there are 16:42 numerous examples through the history of 16:46 humanity than science that was rejected 16:50 we all learned at school that the 16:53 copernicus 16:54 theory of um heliocentric universe was 16:57 not immediately accepted 16:59 far from it we know what happened to 17:02 galileo galilei it was later 17:04 he was prosecuted and had to renounce 17:07 the 17:08 extension of or building up on the 17:11 copernicus 17:12 theory so this is one of the examples 17:16 where science was completely 17:18 not only ignored rejected and prosecuted 17:23 i think that i don't think that at those 17:25 time in the middle ages 17:27 scientists other scientists wrote open 17:29 letters 17:30 if anything that said they said quiet 17:33 not to be prosecuted 17:36 in modern history we know very well that 17:40 the evidence of climate change 17:43 was or still has been dismissed despite 17:47 the overwhelming body of ob 17:49 of evidence of the reasons for climate 17:53 change 17:54 and again we can talk for a long time 17:55 about what are the reasons for 17:58 ignoring or rejecting the science there 18:01 are 18:02 many different agendas apart from 18:05 justice missing 18:07 due to non lack of belief in this 18:11 so the same situation is in relation to 18:14 the airborne transmission 18:16 and this is not only uh in relation to 18:19 copied 19 18:20 but to a respiratory infection 18:22 transmission 18:23 by by airborne route in general 18:27 and the point is that this affects all 18:29 of us 18:30 uh all the time around the globe so it's 18:32 not it's not a minor issue 18:34 and so that it's not something which is 18:37 just related to this 18:38 specific pandemics so 18:42 there was uh no 18:45 public so if we go back to this um 18:48 middle age situation there was no 18:49 particles risk due to 18:51 um believing that the sun circles around 18:53 the earth and not the other way around 18:56 but there are huge risks and 18:58 implications from not 18:59 accepting climate change and or airborne 19:03 infection transmission because of this 19:07 because of these concerns and because of 19:09 the overwhelming 19:10 body of evidence that of the 19:12 significance of such risks 19:14 the scientists felt in the case of 19:16 infection transmission 19:18 that there was no other avenue for 19:20 voicing our 19:22 abuse but in an open letter 19:26 well the open letter was published in a 19:28 very reputable scientific journal 19:31 but i'd say it is still possible that it 19:34 would 19:35 have just added to a body of 19:38 of journal publications and nothing much 19:42 could have happened 19:44 there are several other factors which 19:46 helped 19:47 in this situation to make our 19:50 voices our message heard so the 19:53 factors which immensely helped was the 19:56 um the message was 19:58 the help from the media and the media 20:01 a contribution to spreading the message 20:07 all of us or many of us from this group 20:09 of scientists who 20:10 signed or wrote the petition the open 20:12 letter 20:13 were interviewed by on many occasions by 20:17 journalists and we were in touch with uh 20:20 with the journalists who interviewed us 20:23 so uh once we were 20:26 informed that the uh letter was accepted 20:29 by the journal we went back to the 20:31 journalist and we made them prepared 20:35 that this is going to happen the 20:37 the journal is going to announce this 20:39 open letter so be ready for this 20:42 and indeed they had messages prepared to 20:46 place to appear in the journals as soon 20:48 as the 20:50 open letter was released so this is this 20:53 chorus 20:54 of the media around the world that 20:56 amplified our message 20:58 from the journal and this was ultimately 21:02 what made our message heard and 21:05 considered 21:07 so that's what i'm saying it's not just 21:08 that we prepared and publish an open 21:11 letter but this whole 21:13 set of conditions 21:16 this is this was my first experience 21:20 for leading a large group of scientists 21:22 in in a petition in an open letter 21:24 and maybe the last event so everybody 21:27 around laughs when i say something 21:29 like this but i would say that 21:33 in planning um and 21:38 playing voicing scientific 21:41 opinions as an option this is not the 21:44 first 21:45 option to consider but when all other 21:48 avenues are exhausted 21:50 yes this is this is a way and this is a 21:53 mechanism which 21:54 could help however i'm stressing that it 21:57 should be planned 21:58 and executed rightly if we 22:02 write open letters about any aspect 22:04 which we can't 22:05 uh get done organized 22:09 or influenced in any other ways 22:12 i guess the world stops listening to us 22:15 so we should use this with caution 22:18 but as i said if it's done properly it's 22:20 very effective 22:22 i would also stress that it requires 22:23 some dose of good luck 22:25 which we had in this case 22:29 so this is my answer to your third 22:31 question 22:32 so on behalf of viziac i'd like to thank 22:35 you for taking the time to speak with me 22:37 today 22:38 and also congratulate you for this 22:40 important initiative 22:42 thank you very much for having me 22:46 i would like to direct your attention to 22:47 the iziac webinar series 22:49 spread of infectious diseases and indoor 22:51 environments 22:52 where on a weekly basis going back to 22:54 march a number of leading scientists 22:57 have recorded seminars 22:59 addressing the spread of sars kovi 2 23:01 indoors 23:03 if you are a member of viziac viewing 23:05 these webinars is free 23:07 if you are not a member the us 135 23:10 dollar 23:11 membership fee entitles you not only to 23:13 view these 23:14 webinars but also to a digital 23:16 subscription 23:17 to our journal indoor air thank you