Webinar: Weekly COVID-19 Pandemic Briefing

Emma Ross

Welcome, and welcome back to the Chatham House weekly COVID-19 webinar with Chatham House Distinguished Fellow David Heymann. The theme we’ll be discussing this week is behind the scenes of the global technical collaboration to advance understanding of how the virus behaves and how best to combat it, after our initial discussion of what’s new, in terms of how the science has progressed in the last week. Just as a reminder, this briefing is on the record and questions can be submitted throughout the session, using the ‘Q&A’ function on Zoom. So, not the ‘Chat’ or the ‘Raise Hands’ function.

So, as many of you know, David is at the heart of the effort to evaluate the enormous amount of knowledge and experience that we’re gaining by the day, as the pandemic unfolds, as Chair of the Key Expert Advisory Group to WHO. So, he has tremendous insight to share on what’s going on with the pandemic. Let’s start, as usual, with a look at what’s been learned in the last week about how this virus is behaving and what that means for the response. David, you always seem to have a nugget or two that we find later filters into the wider conversation out there, in the subsequent days and weeks. So, I’m really looking forward to hearing what you think are the highlights of the last week, and your perspective on the rest of what’s going on. So…

Professor David Heymann CBE

Thanks, Emma. You know, I think I would just start by saying, despite all the undercurrent of political discussions going back and forth about who is being blamed for what, the technical arm of WHO continues to work as it always has, and that’s quite well, because through its linking with experts from around the world, either informally, through discussion groups or formally, through its external advisory groups, it’s been providing rapid understanding to this virus. And there are really very few things that aren’t understood at present, but those things are key to the next steps, moving forward. So, we understand a lot about the virus, but the things that we still don’t understand, and I’ll talk about each of them in turn, are, number one, the destiny of this virus. What is going to happen now, as this virus continues to circulate, or will it continue to circulate? Number two, and what is happening in communities, what is the transmission that’s really going on in communities? And three, is this virus causing an immune response in humans that will protect them from future infection with this same virus?

So, starting with the destiny of this virus, I think everybody knows by now that there are seven coronaviruses that somehow have been in human populations. There are four that emerged in the past, way in the past, probably, and that continue to circulate in humans and then they cause the common cold. There are then three, which have re-emerged since 2003 and caused major global alerts. One of those was the SARS coronavirus, one of those is the MERS coronavirus, and one of those is the current coronavirus, and SARS coronavirus 2.

Each of these three viruses has had a different destiny. At least in – the first two have had a different destiny. The SARS coronavirus was a one-time mutation of a virus that entered human populations and circulated. It then has disappeared from human populations, after an effort to contain it in countries where it was causing outbreaks, and also, some recommendations by WHO to postpone travel to those areas, for specific reasons. So, one of those three new coronaviruses, the SARS coronavirus, has disappeared from human populations.

One is a coronavirus, the MERS coronavirus, that’s in animals, in camels, carried in the nasal passageway of camels, and it usually doesn’t cause illness in camels. But it spreads occasionally to humans, still, on a regular basis, and when those humans become infected, if they’re admitted to a hospital with poor hospital practices, it can be spread within the hospital and cause major outbreaks, as occurred in South Korea. However, this virus does not transmit easily from human-to-human.

The current coronavirus, the third new virus, is transmitting fairly easy from human-to-human, and we believe that it’s going to continue to spread for a while, although we can’t be sure. We can’t be sure if it will continue to spread, we believe it will, because it’s been showing that it can very – spread very easily. And it may be a virus that continues to spread in human populations in the future, as have other coronaviruses in the past. But it could also be like other viruses that emerge and then are forced back into nature and disappear, as did the SARS coronavirus, or it could become endemic, as has HIV, which also emerged from an animal.

So, we just don’t know the destiny of this virus at present. But what’s important is to be prepared for the worst-case scenario, in that this will remain with human populations and will maintain its virulence. Although it could mutate in such a way that it’s less virulent, or it could mutate in a way that it’s more virulent, or in a way that it transmits easier, or less easy. So, we just don’t know the destiny, but we do know a lot about this virus at present.

We also don’t understand the community transmission. We believe that it’s transmitted fairly easily in communities, but the serological data, which is a measure of antibodies in humans, which is a measure of their previous infection with this virus, is suggesting otherwise. It’s suggesting that the lockdowns, or that, in general, this virus has – have caused, or this virus in general, doesn’t spread very easily among communities. So, we’re seeing a prevalence of antibody between 1 and 4, 5, 6% in most communities that are looking for antibody and these are looking for antibody with a test called the neutralisation test, which is a test which is fairly reliable. This test picks up infection, antibodies, and then those antibodies are tested in a laboratory to see if they neutralise a living virus, if they kill the living virus in the laboratory. If they do, then they’re considered as protective antibody for this virus.

However, what the Chinese have found recently and reported to WHO is that they’re seeing that many and most of the cases that they’ve had that have been mild, and remember, that’s about 80% of the cases, have not produced detectable antibody, even by this neutralising method. So, we’re still not certain what’s going on at the community level. As far as antibody transmission, we’re picking up antibody, but we may not be picking it all up, and it may be much greater transmission than we understand today, because we just don’t have the antibody test that’s sensitive enough and specific enough to tell us.

And that brings me to the commercial antibody tests, which are on the market, and there are many, and these antibody tests are being validated right now. None of them have been validated independently, outside of the companies in which they’ve been produced. So, we don’t know their real validity and their real specificity. But that will be known in a few weeks because there’s a lot of work going on in the UK, under Sir John Bell at Oxford and under – working with PHE, Public Health England, and in other countries through their public health institutes. There will be information available on that in the next two or three weeks and then people can say, “If I do a self-test on myself, what is the reliability of that test?” Right now, none of those tests can give the individual that privilege of saying whether or not they’ve been infected. And that also, then, raises concern about whether or not to be recommending that people with antibody should go back to work, because we just don’t understand whether these antibodies are protecting people against reinfection.

There are reasons to think that it might not be a solid immunity, or solid protection, because other coronaviruses, those four that are circulating in humans and causing common colds, don’t produce long-lasting immunity. They produce immunity for a short time, but then a year later, you can be reinfected with the same virus. Whether the coronavirus presently, the SARS coronavirus 2, will cause a more solid immunity is not known, although there’s a lot of work been going on, by developing vaccines, by studying vaccines, by just observing populations, that will be able to give us some insight. There have been reported some cases that have been infected with a PCR, that’s the test that tells whether the virus is present, with a PCR positive that then have become negative and then, two or three weeks later, developed some signs and symptoms and again had a PCR positive test.

The question is, and this is being studied right now, is this a recrudescence of an infection that occurred in the human and was not completely eliminated and is reappearing, or is it due to a remaining around of some of the particles, parts of the virus that were infecting them and it’s being detected, or is this really a re-infection? And they’re trying to isolate viruses from those people, who are re-infected or have this reappearance of infection, comparing it to the virus before, to see whether or not this has been re-infected.

So, Emma, those are some of the updates of what we know and don’t know at present and the science that’s been going on in the past week. We’re beginning to understand the destiny of this virus, that we don’t know for sure. We’re beginning to understand community transmission and we’re beginning to understand that we’re a long way from understanding whether or not the immune response provides solid, long-lasting immunity.

Emma Ross

Can I just follow-up on the serology test? So, WHO was saying on Monday there’ve been quite a few of these studies around the world and it appears that a low – lower proportion of people have been infected, much lower than was thought? And if true, that’s way off the numbers that’s been said necessary for herd immunity. I mean, I think the highest number I heard was – a study in Germany indicated 14%. But that’s still lower than expected. I just wanted to ask – okay, they haven’t been peer reviewed, and we don’t know how accurate the tests were, or how representative samples were. But they are looking a bit consistently low. What are we to make of this? Should we congratulate ourselves for it not being worse, the levels of infection, or should we be concerned that there are even more infections to come than we thought there would be? Basically, what conclusions can we draw from the data?

Professor David Heymann CBE

Well, unfortunately, very few conclusions because of the fact that China has reported, and that we all understand, the serology tests that are being used, these neutralising tests, are very specific for this coronavirus. But they may not be sensitive enough to be picking up the antibody that’s produced in those 80% of people who have mild infections, because they’re too low a level in the blood for the test to pick up. That’s a common problem, that’s called the sensitivity of the test, and so we don’t know if there really are many, many more people who have been infected, but the antibody is not being able to be detected, or whether there’s just a fewer number of people infected than we had anticipated. But you’re right, the highest level has been about 14% in Germany, in one community in Germany, whereas, others are more like 1-5%.

Emma Ross

Okay, thanks for that. So that’s really the highlight of the science this week. But before we go any further, I have to bring up the debate about the wearing of masks by the general public, again, as there still is a big confusion to sort out. And actually, a quote you gave to the BBC three weeks ago, when the committee you Chair was about to examine the latest evidence on the issue, has been a bit misconstrued and the misquote is now being use to bolster the arguments of those who advocate for mandatory mask-wearing for everybody, as a way of preventing transmission from those who may be infectious, but don’t realise it.

Given that it’s a contentious debate at the moment, with pressure growing in several countries including in this one, with the Mayor of London calling for them to be used on public transport, while health workers still face a shortage, I thought we should just spend a few moments clearing this up. What’s been attributed to you, and this has appeared in three tabloids in the last week, so I just thought we should just deal with this now, is that you had said that you think that wearing a mask is as effective or more effective than distancing. Could you just clarify your position on the wearing of masks by the general public, outside the hospital or the home setting, especially as it relates to the potential role of everyone wearing masks or other face coverings, to catch the coughs or other droplets of those who might be infected, the so-called ‘source control’ argument?

Professor David Heymann CBE

Okay, well, masks for the general public will not protect against infection and there are many reasons that that is true. Number one is because masks cover the nose and mouth, if they’re worn properly, and they’ll protect droplets from going outside of that person, if they cough. But the eyes are still exposed, and eyes are a mucous membrane, which is also a potential source of infection with the SARS coronavirus 2. So, wearing a mask in the street is a risk, because people might have the false security that they’re being infected and then would not physically distance from others. And, in addition, when they take the mask off, if someone has coughed or sneezed with droplets that have infected the outside of that mask, of course if they’re not taken off properly, the hand becomes infected, the hand touches the face, and a person can be infected from their own hand. So, masks are not preventive for the general population, and studies from influenza have shown that the influenza virus is not protected against by wearing a mask. So, we have some evidence for influenza. We’ll have more, as the period goes on, with SARS coronavirus 2 because people are looking, to see whether they are protective, but the feeling now is that they’re not, based on past history.

Emma Ross

Okay, can I just…?

Professor David Heymann CBE

Now masks – yeah, masks…

Emma Ross

And no, I just wanted to just direct you towards what I’m talking about here is, if everybody is wearing a mask, so nobody’s going to cough on your mask because their coughs have been stopped from getting to your mask, and not talking about walking round in the street outside. Say you’re in a Tube – subway, or a bus, in a crowded place where you cannot maintain the recommended physical distancing. So, okay, aside walking round the street and everybody wearing a mask, so, to catch their coughs going out, do you not see any role for that at all?

Professor David Heymann CBE

Okay, let me try to explain when transmission occurs and how it occurs, and then I think it’ll be clearer to understand why masks can be used to protect others. The virus is transmitted by a cough or a sneeze through droplets that either infect a person directly through the eyes, nose or mouth, or indirectly if those droplets that are infected from the cough or sneeze, or even from speaking, fall on a surface and someone touches that surface and then touches their face and self-infects. So, that’s how the disease is spread. It’s spread through the air in droplets, and it’s spread on surfaces by touching the surfaces and touching your face. So, those are the areas that you want to make sure don’t occur, if you’re trying to protect others.

Some countries have decided, based on further evidence that came out of Singapore, that they will ask populations, all populations, to wear some type of face covering when you’re in public, because evidence from Singapore shows that even a day or so before you begin coughing or sneezing, you can transmit this virus by speaking, spitting, or by some other means, an occasional cough. You can transmit this and about 6% of people in Singapore are believed to have been infected by this way, by having been infected by a virus from somebody who’s not yet symptomatic but does develop symptoms a day or so afterwards. So that’s why some countries are recommending, “When you go in public, wear a mask to protect others.”

Now, if you go in a closed situation, such as a Tube, or such as a nursing home where you’re working, and it’s not known whether you’re infected or not, if you wear a mask, you theoretically can protect others. So, if everybody on that tube, or everybody in the nursing home, is wearing a mask, they’re, in addition to physical distancing, making it less risky that people will be infected from them. But that’s the only condition of wearing a mask, but a mask is not even necessary in the US, they’re just saying, “Pull a scarf over your nose and face, when you’re in a public situation, where you might be able to infect others.” So, masks were never meant and cannot replace physical distancing. But they can be a help if you’re unable to physically distance because of closed environments, such as a Tube, but it’s as long as everybody in that Tube is wearing them to prevent others from getting infected. If you’re wearing a mask and everyone else isn’t, then you’re not protecting yourself.

Emma Ross

Okay. Well, that sounds like what the Mayor of London is talking about, everybody to wear a mask on public transport. I just wanted to move to the arguments about, “You’ve got to use the mask properly, and wear it properly,” and the way you take it off and on. Correct – I’m sure you’ll correct me if I’m wrong, but a lot of that discussion seemed to be centred around wearing a mask to protect yourself. So, if you touch it and somebody’s coughed on it, you might be transferring, but if everybody is wearing a mask, or a face covering, let’s just say a face covering, and you’re in a Tube and you put on your mask when you get on the Tube, and you cough on it, or you speak on it, and you take it off and you screw it up and you put it in your pocket when you get to work, and then you pull the same one out and put it back on when you get home, is there really any harm in that? Because if you’re not infected, your coughing or your spluttering hasn’t got virus in it anyway. And if you are infected, you’re coughing your own infected cough into that mask and you’re already infected when you put it back on. Are the concerns about proper use still a valid discussion, when you’re talking about everybody wearing masks, in order to protect others? Is it still an issue, or am I being – I mean, short of you taking your mask off and wiping it on someone’s face, are you really – is it a transmission risk, if people are reusing and using a hankie, or whatever?

Professor David Heymann CBE

Well, in a Tube situation, if everybody is wearing a mask and wearing it appropriately, and has been in the Tube right along, then there should be no risk of infection from that Tube, except if there are droplets somewhere on the surface that people touch. So, what I’m saying is that if everybody wears a mask properly on the Tube and does – and takes it off when they leave, that Tube should be safe, so that no-one becomes infected because everybody is protecting each other from infection. But if one person is wearing the mask wrongly, and I’ve seen many people, and you have too, either not cover the chin, or take the mask down to take a breath of air and then putting it back on, all of those things will make it less safe and make a possibility of droplets being spread in the Tube, which could then contaminate a surface and when you touch that surface, then you’re at risk.

So, the message has to be together. Wear a mask, wear it properly, wash your hands as often as you can, wash your hands whenever you touch surfaces, and try not to touch your face, and physical distance, even in the Tube, if you can.

Emma Ross

Okay, last question on this mask, as it speaks to one of the reticences of recommending masks, and that is the shortage of PPE for health workers. Do you think it would be a good idea, or even practical, for a government to say, “Ban the use of medical masks by the general public?” They kind of, sort of, commandeer the supply chain, so that medical masks can only go to health workers and close contact carers, the people where they need it to protect themselves, so that the general public is not competing with frontline workers for PPE. Is that doable? Would it work? Is it a good idea? Has it been done before?

Professor David Heymann CBE

Well, what – it has not been done before, as far as I know, although during wars, I don’t know what’s commandeered and what isn’t. Certainly, there have been times when there’s been a commandeering of certain public goods and they’ve been used, for example, to make ammunition or something to that effect. In a non-war situation, I’m not aware that any of this has happened. But the real issue, I guess, and the real question on this issue is, there are ways of protecting others from your cough and sneeze, which don’t involve a mask, or involve a homemade mask. And there are many instructions on the web as to how to make your own mask, if you want to, and how to wash it properly.

I guess the real issue is, a government does its own risk assessment. It understands what it can do, based on the availability of goods, and I’m sure that that’s some of the risk assessments that are going on, and the feasibility studies that are going on in every government, including the UK, at the time that they’re making recommendations. So, you know, when the UK finally does decide to make an official recommendation, and people begin to adhere to that, then they will be responsible also for making sure that the supplies are where they’re necessary. That’s just an obligation that we all ask of our governments: don’t make things into – don’t make recommendations to us that are infeasible – not feasible for us to follow. So, I’m sure these are considerations going on.

Emma Ross

Okay, thank you. I’m just – I thought that might take up a bit of time, to sort through the mask thing. So, our thematics – theme is going to be shortened, so – to leave time for general questions. So I’ll just ask one question on this theme, which is, can you – the technical guidance to the world, as you’ve said, is a very important part of the response, and of course different countries are taking the guidance onboard, to varying degrees, but that’s a whole other webinar, I’m sure. But there is a globally co-ordinated technical collaboration as you say. Can you give us a peek behind the curtain of how the guidance for the world is made, in terms of how the information on what’s going on with the virus is brought in from around the world, how it’s evaluated, by whom, how are decisions made as to what to recommend to the world? Basically, how does this whole thing work?

Professor David Heymann CBE

Well, WHO works on consensus, to begin with, so there’s never any voting. There’s consensus as to what is right and what is wrong. When WHO produces guidelines for countries to use or to modify, they must be based on evidence and that evidence comes from scientific publications, it comes from peer reviewed information around the world, and it comes from input from experts who review that and then make a decision as to whether or not the information is valid and should be used as information basis for guidelines. So, for example, on the mask issue, there’s been a lot published on mask safety and usefulness, and how it’s used. There’ve been many review articles and many different groups have looked at all the different literature and made recommendations in peer reviewed journal articles. That’s then taken by WHO. They review it, with a group of experts, which are geographically representative of the world, and they review that usually in a meeting, but now virtually, and they say, “Here’s what we recommend for guidelines.”

WHO then, has a choice. It can omit those guidelines, or it can take it to a group of external independent experts and let them review it, and they sometimes do that with specific questions, and then they can modify those guidelines as possible, and then they put them out for the public. So, they have several mechanisms to do that. But everything that WHO puts out is evidence-based on what the evidence is showing at the time.

Emma Ross

Okay, I’m going to move on to the questions now. First question from Norito Kunisue from Asahi Shimbun in Japan, a question about Japan. “It’s a country that was spared SARS, and one with a very top-heavy age pyramid, but the lockdown strategy has been late and very relaxed. Why is it, do you think, that so far, we have relatively avoided the pandemic, or does this mean that we’re likely – about to experience the pandemic in the near future?”

Professor David Heymann CBE

Well, there are several things that are very interesting in Asian countries. One of those is that they appeared to be better prepared for this outbreak than some other countries, mainly because, I believe, they’ve had these outbreaks at their doorstep of both MERS coronavirus and SARS coronavirus. So, they’ve strengthened their public health in these countries, and that’s very important, for several reasons. Number one, public health is important for the elderly, to prevent comorbidities from developing; comorbidities that do put the elderly population at greater risk of death, should they become infected. So, population – public health is being very – being stressed in many countries, including in Japan. At the same time, Asians have a custom of wearing a mask to protect others when they’re sick. This is a custom, which has been done for many, many years, not just as the cause of SARS or any other outbreak. For a common cold, many Asians wear a mask, and this is something, which has been very important for them, is they’ve understood how they can prevent transmission and prevent themselves from getting infected, by distancing and by washing hands, which is also very important in the Asian culture.

So, there are some things which have been ingrained in the culture for many years, which have been adversaries, if you would, to transmission of this virus. So, they’ve had to scale up these things gradually. The elderly populations are being protected, many times because they don’t have the comorbidities that elderly populations in other countries do. In fact, Japan is the example for the rest of the world on healthy aging, along with Singapore and some other countries. So that’s some of the reasons that maybe they’re not seeing the same type of an outbreak that is occurring in other countries. And I know Japan and other countries are now spending a lot of time on outbreak containment, when they can, identifying contacts who might be infected and making sure that they’re isolated, as are patients, to prevent further transmission.

So, I can’t give the specific example of Japan, but I can say that in Asia, there has been a general different approach to outbreaks. In the population there’s much more solidarity oriented, involved in preventing transmission to others and in protecting themselves.

Emma Ross

Here’s another country-focused one from – it’s an upvoted question, so a popular one. Zainab Shinkafi-Bagudu on varying tests, variable test results. “We’ve reports in Nigeria of persistently positive results for some individuals, over 28 days, from the national laboratory. However, in at least four cases, a second lab gives a negative result. This is casting some doubt on the reference lab’s integrity, despite the good work it’s been doing, considering our weak system and population size. What could be the reason for this?”

Professor David Heymann CBE

Well, the tests, in the hands of different people, might be read differently and one of the major difficulties, with the PCR test, is contamination from within the laboratory. So, a test that is negative becomes positive. I don’t know the specific case in Nigeria. I do know that the Nigeria Centre for Disease Control is a very strong agency, and they have been involved in Africa-wide training, as well as in Nigeria, on testing, and Dr Chikwe, who’s the Head of that institution, is a Member of the advisory group that I Chair at WHO. So, I know that there is solid knowledge in Nigeria about testing, and about how to test properly, and there are always some cases, which are found different in different laboratories. That’s what’s happening right now in South Korea and so, it would be an important issue to make sure that people do have two negative tests before they’re said to be non-infectious. We believe that period goes up to two weeks after a person is cured, but it may go longer, it may go less. It just depends on the patient. So, you know, what is being seen has to be interpreted with the epidemiological evidence, the signs and symptoms and what’s happening in the patient itself. A laboratory cannot be the final statement of whether a person’s infected or not.

Emma Ross

Here’s one from Victoria Allen at the Daily Mail. “Can I please ask Professor Heymann if he believes that antibody testing won’t end the lockdown and should not be used to relax the rules? It sounds as if he’s saying people may not have long-lasting immunity, so is it possible that people in the UK are only immune for a few weeks or a month before becoming able to get and spread the virus again?”

Professor David Heymann CBE

That’s the question that everyone is trying to answer right now in the technical arm of WHO, and the answer is, it’s not known. It’s not known how long antibody protection lasts. It’s not known if all people with antibody can be detected with current testing. A whole series of things that are going on, and remember, this is a new virus. So that question can’t be answered. But what is clear is that countries who – that were considering a passporting activity, in other words, having people who have antibody be reinserted into the public and being fairly sure that they won’t be re-infected, can no longer be a policy. And those policies are mostly on hold, waiting to see what can be determined about protective immunity from this virus.

Emma Ross

So, the testing – just to follow-up on that. The tests that are useful, coming out of lockdown, if you follow the recommended case finding isolation are the antigen tests, aren’t they? That using those is going to be important, or do you think that’s been overplayed?

Professor David Heymann CBE

I think countries will decide, but I think most countries will want to stop discrete outbreaks if they can by doing the routine outbreak containment measures: identify patients, isolate patients, trace their contacts, put them under observation for two weeks somehow and if they develop a fever, test them, and if they’re positive, isolate them. That’s standard outbreak control activities. In some countries, they’ve been continued. In other, they’ve been discontinued because of an increase in patients that needed attention in the hospitals, where they needed to provide the testing. And now, I think, countries will again be reconsidering what they want to do in an unlock phase. But I think it’s important for us all to remember that governments are facilitating what we need to do, and that is to understand and practise how we can protect others and prevent ourselves.

Emma Ross

Can you do the routine outbreak containment without diagnostic testing? Or do – in order to really unlock safely, do we have to wait? Does a country have to wait ‘til it has the capacity to do case-finding and isolation and contact tracing and quarantine? Do you need the diagnostic test to be at massive capacity or can you continue to do containment, without a diagnostic test?

Professor David Heymann CBE

Well, Emma, first of all, my belief is that a country will develop its strategies, based on what’s feasible in that country. A country in Africa, without PCR testing, cannot use it at all. So, they have to depend on other means of making sure that people in communities, where there’s no access to a health system that might be able to PCR test, they have to understand how they can protect themselves and protect others. So, I’m coming back to this same issue. The population has a great role to play in this. Governments will be determining their unlocking strategies, or their transition strategies, based on what is available within the country, where they want to invest their resources, and how they want to proceed. And no country yet is right or wrong at present, because everybody is building the ship as it sails, trying to understand what’s most important.

Emma Ross

But can it be done without diagnostic testing, in your vast outbreak control experience, can these things be kept on top of without…?

Professor David Heymann CBE

Well, you can certainly do a lot by looking at contacts. If they become sick, just isolating them, without a test because a test isn’t available many times. And so, the logic would be that if this person has had contact in the last few days, after 14 days, and has illness, then that person should be isolated, if there’s no testing available. So yes, there is a way of doing outbreak containment activities, even though a test might not be available. This happens at the beginning of all outbreaks, when there’s no test available. You just isolate those contacts who become sick.

Emma Ross

Okay. I’m going to go to a question from Martin O’Neill. “Given the trajectory that countries have pursued of fairly aggressive social distancing strategy in March seemed to be on. Can you comment on the likelihood of a second wave, and what that might look like?”

Professor David Heymann CBE

I can’t predict a second wave. I don’t know what will happen, and nobody else can predict either. But modellers are showing what might happen, if there is increased transmission after the transition period is over. But I think that most countries understand that when they do begin to transition, they must be very cautious in what they do, in unlocking various sectors and they need to take into full consideration those issues. For example, if there’s a decision to open up schools, then there needs to be a policy about what they do about the mass gatherings that occur in school situations, for example. They have to be thinking ahead and being sure that what they’re doing minimises the risk of a second wave or of increased transmission occurring. So, when there is a transition, there needs to be in place a monitoring system, a surveillance system, to determine if transmission is increasing. And there needs to be a sector-by-sector approach, and maybe even a region-by-region or a district-by-district approach, where they will begin to unlock in certain areas where they feel the transmission has been less, hoping that it will stay at a low level. But I expect that no country will open up everything at the same time. But I may be wrong. I would expect they will do it, based on a risk assessment in various areas in the country.

Emma Ross

The top-voted question at the moment’s from Colin Barrow. “How significant are the early findings from studies at USC and Stanford, showing that asymptomatics might be much more numerous than previously thought?”

Professor David Heymann CBE

Those are studies that have been done showing virus shedding, and they’re important studies. All that we have evidence for now, in the real population, is from Singapore, which shows that about 6% of people who were – became sick, had had exp – or who were sick, had had exposure to someone within the day or so before that person developed signs and symptoms. That’s – of the illness. That’s all we know at present. So, the figure is 6% of people who are asymptomatic, but who go on to develop symptoms, could be infectious the day or so before they are showing signs and symptoms. We know nothing in the community yet about those people who are infected and never develop symptoms, or never understand those symptoms. Whether or not they could spread it by – when they talk, spitting by accident on people, it’s just not known. That’s why physical distancing is incredibly important for us all to continue, until we understand completely the epidemiology and transmission patterns of this virus.

Emma Ross

Okay. Here’s another upvoted question from William Crawley. “If, for economic and social reasons, the lockdown were to be relaxed, would there be any demonstrable medical value in excluding particular age groups, e.g. the over 70s or even over 40s from the changes?” I guess the changes being the relaxation.

Professor David Heymann CBE

Well you know, when transition occurs, I think countries are considering how can we best protect the elderly? Those over 6 – 70 and especially those with comorbidities. And some countries are already practising things such as, “Please leave our supermarket empty of anyone except the elderly,” at a special period of time each day and it may be that those are some of the norms that come into being. But it will be a responsibility of the elderly to make sure that they are not taking risks that could expose them to infection, should they wish to. So, they need to social – physically distance. They need to practise the same things that everyone else needs to practise. But they are a population, which needs special attention. Nursing homes in particular, homes for the elderly, need special attention to be sure that there is not transmission occurring, even from people who haven’t yet developed symptoms. And so that may mean that they want their staff to do things, such as wear a mask properly, when they’re taking care of patients and can’t make sure that there’s a physical distance between them and patients. All these things are being discussed by every country, and they will come out with their own recommendations, based on their culture and based on what will need to be done in the future. But the elderly are certainly a priority population that all countries will be considering.

Emma Ross

Okay. A question from The Guardian, Patrick Wintour. “I think last week you were expecting a report from WHO, from Iran. Can you talk about that and give an assessment of how Iran is coping, including validity of their statistics and lockdown?”

Professor David Heymann CBE

Well, I can’t – nobody can validate statistics from any country. So, I wouldn’t even attempt to do that. What we go by is what is reported to WHO, whether it’s the UK or Iran. The Iran Head of the Public Health Institute did participate in our meeting on Friday with WHO. He presented information. He is presenting more information because we’ve asked that he come back. The information that he initially presented was very well-received by the committee. It shows that there is a decrease in new cases occurring. They’ve had some physical lockdown, and they’ve been able to decrease transmission and some of the actual activities in Tehran are beginning again, though there won’t be mass gatherings. And at the same time, he presented information that showed that just like in China and other areas, about 80% of patients are – the majority of patients have asymptomatic disease.

He’s been asked to provide more information about the age-specific attack rates of this virus, and he will be doing that at our meeting coming up either this coming Friday or next Monday – next Tuesday, rather. And he’s agreed to participate in the meeting again and he shared graphs of what’s going on and clear from those graphs, the transmission is decreasing. So, that’s the information we’ve had from Iran. Again, openly transparent and providing what the government agreed that they would present to WHO. But nobody can validate that, and that’s something to do after the outbreak. We now need to work together and make sure that we’re all understanding how we can work together to stop this pandemic, if possible.

Emma Ross

[Pause] Sorry, sorry. We’ve reached the end, but there is one more question I think is quite important I just wanted to squeeze in and that’s from Kaleem Hussain. “There are certain reports appearing in the papers that BAME communities, that’s Black, Asian and minority ethnic, are more prone to getting infected or dying from COVID. Is there any evidence to confirm whether there is any validity to this?”

Professor David Heymann CBE

Well, there’s a lot of work going on and, you know, in some cultures and in some societies, minority populations don’t have access to good public health messaging and are not as healthy, many times, as are other portion of that population. This occurs often in minority populations in all countries and therefore, – and they don’t have as good general health as do others. Maybe they have a problem with obesity in that particular group. Maybe smoking levels are higher in that group. Maybe there are other things that are higher in that group because of genetic differences, such as hypertension, or some other genetic-linked diseases. And so that needs to be sorted out, whether it’s actually genetic, because they’re of a different ethnic group, or in fact because they’re just a group that has a different level of comorbidities that are causing this. We know that people who are overly – overweight, especially morbidly overweight, have a very poor prognosis, if they become infected. So, if that’s occurring in any specific ethnic group more than in others, then that would be what is causing increased mortality, not the fact that it’s a different ethnic group. So, all this needs to be sorted out and is being sorted out in studies in the United States, in the UK, and in other parts of the world.

Emma Ross

Okay, thank you. So, we’ve reached the end. Again, naughty, I’ve gone a little bit over, sorry. So, the recording of this will be on the website, Chatham House website, later this afternoon. And for any Journalists who may want to follow up with David, please do email the Press Office to book an interview: [email protected]. And please, everyone, join us at the same time next week, when we will have a special guest on with David, who will be Professor Johan Giesecke, an Advisor to the Swedish Government on their response. So that should be a really interesting discussion and hope to see you all next week. Thank you very much.

Professor David Heymann CBE

Thank you, Emma, and thanks everyone.