Below is an automatically generated transcript of our Podcast "Dealing with airborne viruses". Please allow for some spelling and grammatical errors within the transcript.
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More about how clean air can affect the quality process for you and the workplace. This month that we'll be finding out how you can protect yourself from viruses from today's COVID-19. right through to those still to come. My name is Dusty Rhodes and joining me is biosafety consultant, Dr. Jonathan Gawn. And from Camfil Chris Hughes, a little bit about Jonathan Gawn. He is a former HSE, Principal specialist inspector for biological agents, university biological safety officer and research scientist in UK Government, academic healthcare and industrial containment laboratories. He's currently the chair of the biosafety steering group for isdr and represents the ICR membership on the biological Safety Leadership Group. Chris Hughes from camfil has 28 years experience working in the life sciences and healthcare market working regularly with senior level executives, academics, regulatory compliance officers, and government representatives across the United States, Europe and Asia. JOHN, let me start with you. COVID-19 is the latest in we have to recognise a long list of viruses of the last few decades we've had SARS, Ebola, the Zika virus, etc. Can you briefly explain to us about viruses and how they affect the human system? Yeah, hi dusty. Yeah, so viruses are, as you've said, there are many and varied they're a micro organism,
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where they differ from a lot of the microorganisms that people generally think about, which are, you know, bacteria, and the sort of things that you can pick up from, sort of dirty surfaces and things like that. So bacteria can exist on their own, they're alive on their own, they can replicate on their own viruses are generally speaking, much simpler. And they cause us trouble by getting into our bodies, they infect our cells, and they hijack our cells to produce new viruses. And that's what we're seeing during this current pandemic.
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Generally speaking,
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there's a vast array of viruses, lots of different ways that they can infect us and different viruses will infect us in different ways. So, to think about some of the viruses that you may have heard of, so, HIV, for example, is you know, you need very close contact to transmit HIV. So, sexually transmitted or if you can, you can get it from blood transfusion, so blood to blood contact,
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whereas something like influenza and SARS is a respiratory virus. So it tends to infect us via very often via the air sometimes, by picking it up off of surfaces and getting into our lung cells.
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Viruses will causes illness and generally speaking, depending on where they infect us, so, HIV infects our blood cells, which means we can no longer mountain immune response. Whereas something like influenza or
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SARS Coronavirus to get us into our lung cells and causes us illness by affecting how our lungs function. And very often as well, we will be able because of the way that our immune system reacts to that virus. And I think that's certainly something that is coming into play and in the current pandemic, so COVID-19 is very much generally a lung disease, it causes we have difficulty in breathing for various reasons due to the infection.
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And really, the viruses will be transmitted in lots of, you know, in various different ways. Obviously, you know, if you're, if you've got generally speaking a respiratory virus, like SARS Coronavirus, to, which causes COVID-19
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will be breathed in. And so whilst there are different ways in which you can catch it, you can catch it by through hand to mouth contact from the surface, for example, but actually the dominant one appears to be via the air. And that's what's been informing a lot of our
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a lot of measures to try and control their viruses.
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I've heard stories where I understand that if somebody is in front of you, and they breathe on you that there is a chance of the virus getting through to you. If they wear a mask, then obviously that helps prevent that. But then I've also heard stories of people who've been on a bus where somebody with a virus was on the bus 20 minutes beforehand, yet the virus was still able to transmit. Can you tell me a little bit more about how air viruses go from A to B? Yeah, so certainly, so a virus like SARS Coronavirus, two, which is the virus that that we're dealing with in the covid 19 pandemic.
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Like I say there's usually different mechanisms by which they can transmit.
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And those different mechanisms, one will, will, will predominate. So
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the usual way for a respiratory virus to be to become infectious is that you breathe in droplets that have been expelled by an infectious person. And people are producing droplets all the time, they're producing droplets, whilst they're talking, I'm producing droplets now. And some of those smaller ones that are smaller droplets, we would term an aerosol. So you can have an infectious aerosol and containing the virus, and obviously, people that are nearby, will breathe that in, which gives the virus access to your lung cells, which are the cells that it likes to infect. And once that infection has, has started, you've got it until your immune system manages to beat it.
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And or there is some kind of, you know, potentially some kind of treatment that that supports you to for your immune system to clear that there are other routes, and with SARS Coronavirus, two they appear to be the less dominant routes where you might be able to pick that up. So SARS can survive in respiratory secretions, for example, on a surface for a period of time.
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So if somebody else comes into contact with those secretions, and then says, say, touches their face,
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then you're once again giving the virus access to the types of cells in your respiratory system that it likes to infect. And I have to say the dominant one appears to be the airborne roots of the breathing in root. And what we can see from this virus is that most people will be infected by if they're within a metre of an infected person, which would suggest that actually that there's sort of short range airborne transmission going on. But there are other routes that it can get to you. They're just not as dominant. Let me ask you, how much of the virus Do we need to inhale in order to be infected? Well, once again, that is very much something that's dependent on the virus that you're dealing with. I would suggest a very often what you'll see with viruses with new viruses. So
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when I say new virus, this is a virus that jumped out of an animal population into humans relatively recently, probably sometime in 2018. It's, you know, it's jumped into it's found a way to infect humans through mutation. What you tend to find with viruses like that is that they're not very infectious. And we've actually seen that with SARS Coronavirus, too. So in the first wave of this pandemic, the strain that was predominating
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wasn't particularly infectious. And so you probably have to breathe in quite a lot of virus, I couldn't put a number on it, but you probably have to breathe in quite a lot of infectious virus, in order for that virus to establish an infection. What we may be seeing with this new variant is that actually, it's adapted a little bit better to infecting humans. And actually, it can generate a productive infection, it can, it can really start to affect people
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much less of an infectious dose is actually the terminology that people would use there. So it varies from virus, the virus, and it can change with strains of virus as they as they adapt, and as they mutate. Okay, just thinking about a COVID-19, which, of course, is what everybody's thinking about this year. Have you any examples you can give me of an outbreak in a working facility or within a building or processing plant or something like that? Well, I think there are an awful lot of with COVID-19. I think there are you know, there are lots of examples of, you know, outbreaks within sort of populations that have been
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people that have been working close together, I know that there are some published studies where people have been infected by the virus in a restaurant and examples where they've been infected by the virus whilst on an aircraft.
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So, you know, there are there are some examples out there, if you look in the literature of, of, of, you know, sort of being able to map outbreaks.
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Very often it's not clear where the virus has come from. And sometimes it's clear that actually the outbreak has been because you've been in the workplace with someone else that's been infected or been in the home with someone else's been infected.
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Can I ask you about aircraft things you mentioned them. They say that an aircraft is actually one of the least likely places where you are going to pick up a virus because the air is turned over. So
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Frequently, do you believe this? Or should we take with a pinch of salt? Or? I think generally speaking, I think he can believe that I think the, you know, the way that the the air moves in an aircraft is,
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you know, you know, it's pressurised The air is actually moving, you know, relatively quickly, it's being, you know, pumped in and pumped out to maintain pressure.
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So, like, say, the turnover of air, the dilution of air tends to, you know, the air comes in at certain points in the cabin, and it gets extracted from certain points in the cabin. And I think that's,
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that's probably true. I think there are, however, some issues in all, you know, potential workspaces and places where we might find ourselves where we need to be mindful of the direction the air is moving. Because obviously, you know, if, if air is moving directly between a person who is infected, and a person who is uninfected, you can expect, you know, perhaps that two metre rule to start breaking down a little bit. So now, Chris, from camfil, is with us, Chris, what do you make of all this? Well, it's, it's a fascinating topic, dusty, for sure. And listening to john there, and all his experience. And one of the fascinating things for Caterpillar has been
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joining the dots up, as we like to say, so it's understanding the biology, the microbiology that's going on, and tying it in with the air filtration, clean air aspect, and the ventilation, really joining those dots up together. And we've been engaged in quite a number of studies that have been funded unsurprisingly, since the pandemic. And they really accelerated as we got into the first lockdown, ranging from all areas of singing, music, speaking through the dentistry and healthcare. One of the fascinating things is just the variety of things and factors that can also risk within these different activities. Okay, let me go back to john. And we've got a great good overview of viruses at the moment, I want to ask Chris, in a moment about the control of airborne viruses within workplace environments. But first, what about more in lab conditions? How do you control airborne viruses? Yeah, so obviously, one of the one of the interesting factors here is that, you know, people have been
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working in laboratories with large amounts of airborne viruses for many, many years, decades, in fact,
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in for research purposes, and when I say large amounts of viruses, I mean virus that's been that's been grown up into to, you know, to levels that are way in excess of what you'd encounter
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if you were to be in proximity to an infectious person. And we've been using sort of, you know, various principles in the laboratory, and the principles of biosafety, they're actually, you know, they're not just the principles of biosafety, they're the principles of dealing with any kind of hazardous substance and applying those principles in the oratory to stop us from to stop people that are working in the lab and from
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becoming infected with the virus that they're working on. And with airborne viruses in particular, or viruses that can be transmitted via an airborne route, which would include things like influenza and SARS and SARS Coronavirus 2
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one of the key features of that control is the movement and filtration of air. And we've been using
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safety cabinets, which use airflow to make sure that you know, any airborne contamination is taken away from the research worker in a direction that you know, it's either sucked away or blown down, and the laboratories themselves
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for dealing with some of the more harmful airborne viruses, and a lot more harmful microorganisms generally, in fact, and so things like tuberculosis, for example, would have to be handled in what we call a containment level three laboratory. And, you know, and anything above containment level three, that requires anything above containment level three, uses airflow to actually suck air into the facility so it's not blowing contaminated air out that is then filtered and taken somewhere else very often just vented into the atmosphere after passing through a filter. So we've actually been using ventilation and air flow to control exposure to airborne viruses and then aboard for a very long time.
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Obviously, you know, this is a public health issue, it is the this virus is out there on the streets and in our workplaces, and we can't work inside a laboratory However, what we can do is apply some of those principles to the way we design our buildings. Well, let me ask Chris then about that. Because you know, laboratory conditions are one thing workplace is another and what kind of controls are in place in workplaces?
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There are really two key areas here that we're focusing on. And that is, we need to look at the air that is coming into that facility, making sure that it is filtered as efficiently as possible. So that we know Yeah, we're bringing in is clean in inverted commas to a regulated level. So it's standard driven, internationally recognised standards. but crucially,
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it is what goes on in what we termed the occupied space. So the activity that is going on in the room, whether it's a school, or a lecture, theatre, or office, you know, how many people are in there? What are they doing? How long are they there for? So how do we protect those people,
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it's filtering the air away from their breathing zone, as far as possible setup a bit high level or low level or a combination of both.
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So it really is looking at individual sectors, I suppose, and situations dusty about bringing the best solution, but using tried and tested products, and approaches and risk assessments. Tell me tell me about another proven system, the cache hierarchy of control, at the moment, the hierarchy of control, if we look at government guidance, we're all working from home, you know, we're recording this from our offices at home. Normally, we would be in our offices with our colleagues. So that whole thing of physical separation is the first thing if we don't have to be together, then we shouldn't be. And as we roll down through if that's not the case, if we have to be together, what are engineered solutions, you know, how can we look at protecting that environment. And that comes back to what we were talking about just now dusty, you know, filtration approach the air that we're feeding into these spaces, how we're moving around, how we're filtering it, how we're monitoring it,
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and so on, and so forth. And, actually, interestingly, in the hierarchy of control, and john, please correct me if I'm wrong here, but almost the last thing we should be doing is wearing a face mask, because on the COSSH, the having to resort to personal protective equipment, such as a face mask, is the last line of defence.
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Well, now I'm interested, I'm interested to hear what y'all has to say about that. The last thing we should be doing is wearing a mask. Yeah, I mean, I think what Chris means is that actually, it's the it's the last type of measure that you would you would generally employ. So the COSSH hiring hierarchy of controls, so this, you know, this is what underpins an awful lot of the principles of,
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of controlling people's exposure to harmful substances. And that includes
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biological substances, like viruses. So at the top of the list, and like I say, this hierarchy,it's a hierarchy of reliability, if you like, so, you know the measures that you have at the top of the list are the ones that are going to be most effective.
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The ones that you have near the bottom of the list are the least effective. So at the top of the list, but in the hierarchy of control, you you know, if you can you eliminate the agent entirely. Now, obviously, that only really works if you're deliberately working on something. So you can, you know, if you, if you can avoid working on something harmful, you should avoid working on it, then next on the list is, you can substitute that for something else. So rather than work on something harmful, you work on something that isn't harmful that and that takes you to the same place or work with something that's
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less harmful, that takes you to the same place. And then you're in controlling things, then you're into where you can't eliminate it, you can't use something else. So we're into. And this is, and this is really where we're at with with COVID, you know, it's there, it's in our workplaces, he's on the street corner, we cannot avoid the fact that we are going to be exposed to it at some point.
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So you employ control measures in order to reduce the likelihood that you're going to come into contact with that substance and be caused harm as a result of that. So
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one of the key measures there would be to create a barrier between you in it so can you put basically Can you put it in a box?
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You know, I don't think we can really do that.
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There are other controls
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measures. So there are, you know, we call them engineering control measures and air flow and filtration would be engineering control measures that might, you know, if employed properly and effectively, and can be used to reduce your exposure, there are other things that you can do as well.
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So, you know, as we were talking about earlier on in terms of coming into contact with surfaces, if we are going to, you know, reduce the risk of coming into contact with a virus from surfaces, we need to, you know, we need to clean better, we need to wash our hands, all of the measures that we're actually hearing from the government and various governments around the world
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as being important for the control of the virus.
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And, you know, we can, and we can also, we can also change the way we work. So, you know, as Chris pointed out, you know, we can we can reduce the likelihood of coming into contact with it by working at home or working via zoom or taking the car and not the train all of those kinds of things.
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I think I think what he was saying about
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masks is that that's down the bottom of that hierarchy of reliability. So it's the least it's the least reliable, it's effective, but it's the least reliable way of preventing exposure in that list of things that I've just given you. All right. There are many types of clean air technology, Chris, that are labelled as the most effective solution. What considerations Do you think somebody is somebody should take into account when choosing the right clean air solution? Well, I think
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we talked about earlier dusty, it does depend on the situation. So if I take two somewhat extreme examples,
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it if we look in a lecture theatre, at the university, so at the moment, they're very challenged, because we're in the middle of winter, temperatures outside a cold. And the advice right is to increase ventilation. So that means opening windows. But obviously, from a thermal comfort point of view, that's not very good. So we need to look at things like the number of people in that lecture theatre, where they spaced how they're seated, the activity or the size of the room. And then you can use mobile air cleaners just strategically placed. And they can be incredibly effective. You know, they have filters that are tested, manufactured and tested to latest global standards, so we can prove their efficiency. And as john has said, previously, these filters have been used for decades in these high containment laboratory settings. So there's plenty, plenty of proof of principle out there. And then if we go to a different setting, like a dentist, for example, a whole different set of parameters. But we've learned and we continue to learn so much more. So we can apply exactly the same products
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into that setting. But because we understand what is going on in that setting, we understand the risks, the aerosols and the droplets, what's being produced, and how they behave, you know, the characterization of those facilities. So again, we can use the same products. And we can position them specifically, we can help clients understand what they have already. And we can provide them with some logical, simple steps based on existing technology to help them out. And I think crucially, this is about risk mitigation. You know, it's not risky elimination, this is part of
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their COVID guidance and protocols keep working, but we can, we can massively reduce risk. Risk Mitigation is a great way I think of summing it up. And from listening to what you gentlemen are saying it looks like you know, kind of cleaner air is a very critical part of that risk mitigation. We leave it there for this week, john gone. Thank you very much, and Chris Hughes as well. Thank you to you both. Thank you. Thank you. If you'd like to find out more about this, just follow the links in the show notes. You'll find them in the description of this podcast on your phone or whichever device you're listening to us on. They include links, contact details and anything else you might need to get more information. Our podcast today was produced by camfil, a world leader in the development of production of air filters and clean air solutions to remember you can get the podcast automatically just subscribe. Just click the subscribe button on your player right now. But for now for myself just erodes and from Chris and from john. Thank you very much for listening. Take care.
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