Webinar: Weekly COVID-19 Pandemic Briefing – Asian Responses and the Experience with SARS

Emma Ross

Good morning, and thank you for joining us for this week’s Chatham House COVID-19 briefing with Chatham House Distinguished Fellow, David Heymann. Our guest today is Professor Gabriel Leung, the Dean of Medicine at the University of Hong Kong. He’s recognised as one of Asia’s leading experts on epidemiology and global health and among the world’s top experts on SARS and COVID-19. He and David worked closely together on the containment of SARS in 2003, and for this response, Gabriel is advising Hong Kong and the government of mainland China and was among the experts on the joint WHO China mission that investigated the outbreak there in February. So, welcome, Gabriel, and thank you for joining us today.

Before we launch in, I’ll just cover the housekeeping stuff. The briefing is on the record, as always, so you can tweet, no problem. Questions can be submitted using the ‘Q&A’ function on Zoom. Upvoted questions are more likely to be selected, so if you like questions and they’re similar to yours, please upvote. So, welcome, Gabriel, thank you so much for joining us.

Professor Gabriel M. Leung

Hello.

Emma Ross

Hi, I was hoping you could kick us off with how you would characterise the experience in East Asia thus far with the pandemic, and the responses to it, and where you are now with it?

Professor Gabriel M. Leung

Well, I think that what I should say, first off, is grouping geographies together is perhaps not really appropriate. What I would say is East Asia, or at least selected places in East Asia, have had the commonality of SARS or MERS. So, if you think about mainland China, Taiwan, Hong Kong, Singapore, these are the places that had gone through SARS, and South Korea, MERS. So, that would be the basis of really grouping them, or whereas Japan actually never went through either of them. And, in any case, the East Asian, or Northeast Asian epidemics, in terms of the first wave, have mostly actually been completed. What you have been seeing since are largely anecdotal or sporadic flare-ups, like we are now witnessing in Beijing, and like we have been witnessing, over the last few weeks, in South Korea and in Japan. So, I think that in terms of the phase of the pandemic, most of these East Asian, or Northeast Asian, countries and places are probably a month or two ahead of Europe and most certainly, the Americas.

Emma Ross

Okay and what – have there been any common features of the responses there that differ from what we’re seeing in other parts of the world?

Professor Gabriel M. Leung

I think that you see a lot of heterogeneity and variability across the world and I think that, by and large, it would not be an unfair comment to say that East and Northeast Asian countries generally have applied more substantial and quicker interventions, with mostly the implied consent of their populations, as compared to, say, the Americas at the moment.

Emma Ross

I want to turn to David. Thank you for that, Gabriel. Do you have any thoughts, David, on what you think the rest of the world can learn from how these countries are handling the virus, given the variety of responses we’re seeing across the world?

Professor David Heymann CBE

You know, I like to classify the response into two different types of response. One is an epidemiological approach, which is looking where transmission is occurring, which is finding people who are infected, which is doing outbreak control studies, looking to see how they can trace the contacts, a whole series of things that makes the outbreaks stop and not spread into communities. And these have been activities that have been going on in many parts of East Asia, and also in the rest of Asia as well, in Vietnam, for example, where they’ve been able to do outbreak containment activities and stop the discrete outbreaks. Countries, in many other parts of the world, looked at this as transmitting possibly like influenza, which has proven not to be the case, and therefore, they thought they should instigate their mitigation plans for influenza, which is what led to the closedown of social events and other events that they closed down, including locking down entire sectors of the population.

So, this disease does not spread like influenza. Countries that realised that early and approached it epidemiologically, which is finding cases, doing the contact tracing and containing those outbreaks, seem to be ahead today. They’ve been able to keep their reproductive number very low. Countries in Europe have done the same, the countries that are now ahead are those countries that continued with an outbreak containment type approach, such as Germany, Switzerland, Denmark and some of the Scandinavian countries. So, there have been varied responses, as Gabriel said, it’s been heterogenous in how the responses have been done, and I think the final analysis remains to be done. But I think that the circuit breaker activities that are going on in Asia, which maybe Gabriel can describe, for some parts of Asia, which is intermittently closing the sectors and then opening up again, has been very beneficial. Gabriel, can you say anything about that?

Professor Gabriel M. Leung

I think that certainly, you are seeing very drastic measures, you can call it circuit breaker, or whatever, currently, I mean today in Beijing, and this is after 100 cases, give or take, and with a heavy concentration in a particular, very large, wholesale market in the suburbs of Beijing, the national capital. Now, of course, it’s a response that we haven’t seen with that kind of absolute number in most other places. David mentioned circuit breaker, I think that term actually came from Singapore. Singapore has lifted that circuit breaker now, but Singapore has seen a highly, sort of, variable outbreak, depending on the status of the population, or the subpopulation groups.

So, Singapore has got about 5.5 million people, 4.5 of whom are Singaporean citizens, or permanent residents, and then the other million, give or take, are expatriates of one sort or another. About one third of this group actually live in fairly crowded conditions in dormitories and they oftentimes are – do some of the harshest and the most difficult jobs in Singapore. And if you look at the attack rate of that group, it’s round about 11/12%, compared to 0.03% in the rest of Singapore, about a 350 to 380 times difference. So, I think that you have to look at that outbreak by population subgroups to really understand the dynamics and also understand the conditions, and that’s why they had the circuit breaker intervention, I think.

And as for Japan, which never actually went into a full lockdown like mainland China, or, for that matter, Singapore just now with that circuit breaker, which is really a complete lockdown, is fairly similar to South Korea and both countries, I think, have done superbly well, in terms of their contact tracing, in particular, and also, ramping up testing on a massive scale. And that, I think, is the commonality of most of these Eastern/Northeast Asian places, including, of course, Taiwan, which has had a very, very mild first wave also, probably made easier by the island economy of itself, much like New Zealand.

Emma Ross

We’re talking about aggressive testing and contact tracing being a commonality and it’s been said that lockdowns came in many parts of the world because the capacity to do that was just not there and there seemed to be very little other choice. What are we to make of what happened in China, was that the same thing, the lockdown, because they did not have the capacity to test and trace, or was it just another layer and they did have the capacity? How do we relate the massive lockdown in China with their testing and contact tracing? Was it a replacement, or a…?

Professor Gabriel M. Leung

No, no, no, it’s not a replacement at all. I mean, China has done more tests, I think, in absolute terms, than any country, and you remember, of course, a few weeks ago, it tested before the lifting of border restrictions sub-nationally between Wuhan, in Hubei Province, which was the original epicentre, and the rest of the country, they actually tested within ten days all 11 million people who live in that city. So, no, testing is not an issue in mainland China. The so-called lockdown, or the cordon sanitaire, which sort of descended in and around the original epicentre of Wuhan and the half a dozen or so neighbouring cities, that was really to try to prevent the continuous seeding from Wuhan, as an epicentre, to the rest of the country, domestically. So, that was really the real reason, and you are actually seeing the same thing with a lot of cancellation of flights and trains and ground transportation out of Beijing in the last 48 hours. So, it’s in addition to test and trace, not as a replacement or a substitute for test and trace.

Emma Ross

And do you think, either of you, that in other parts of the world, that’s the same thing, or has it been seen more as a stopgap while you get test and trace capacity up and running?

Professor Gabriel M. Leung

I think that it really depends. It depends on which country and which context you’re talking about, but I do think that, yes, test and trace has lagged in quite a few countries. Particularly in Europe and definitely in the Americas, and I think that that’s just something that the whole world needs to do better, as we try to, if you are still I the first wave, try to exit from the first wave, but certainly in preparation for a probable second wave, especially combined with, let’s say in the Northern Hemisphere, seasonal forcing during the Autumn/Winter.

Emma Ross

David, do you have something to add about that relationship between the lockdowns and the testing tracing capacities?

Professor David Heymann CBE

Yeah, no, I think that Gabriel has said it right and countries that did lock down without doing contact tracing did it because they just couldn’t continue to do the contact tracing. The UK started with contact tracing and with making sure that they were testing strategically, and then they locked down in order to protect the health system and by so doing, they switched all their testing to patients and looking at patients who might need hospitalisation, and therefore, there was a drastic change in how they did deal with the outbreaks.

I’m going to disagree a little bit with Gabriel on one thing, and that is that I, myself, don’t believe that it is inevitable, in certain countries, that there be a second wave. If countries can get the contact tracing and all these elements in place to deal with outbreaks when they occur, in the low season of transmission, which appears to be what we’re seeing in the Northern Hemisphere right now, they may be able to keep that second wave, if there is one, very low, and maybe not even cause a major increase. But, again, that depends on excellent contact tracing and excellent outbreak containment activities, which are costly to do, and which many countries will likely not be able to sustain, as they begin to see people coming into the country who are infected. But, again, it’s not a strong disagreement, it’s just rather trying to get Gabriel to defend a little bit more why he thinks that a second wave is inevitable, and maybe that’s not what he meant to say. So, Gabriel?

Professor Gabriel M. Leung

I’m not sure that it’s inevitable. I hope you’re right, David, very much so, but I think that it really depends on what the mixing patterns and the mobility patterns become, as we, sort of, move into the Autumn/Winter season in the Northern Hemisphere. I think that it will be fairly instructive to focus on, say, Australia, New Zealand, who are now, of course, as we enter the Summer season, they are entering their Winter season, but I think it’s slightly different for the rest of the Southern Hemisphere, because they actually are just going through the first wave. So there isn’t actually that initial so-called, sort of, herald wave or that initial kick, which Australia and, to a lesser extent, New Zealand, did come through, but I think that it’s still only going to give us some idea and not the whole picture, because those two countries really didn’t have a very significant first wave, in comparison to most of the Northern Hemisphere. So, I hope you’re right, but I think that if mixing and mobility continues to be lifted, however cautiously, by Autumn/Winter, Northern Hemisphere, you are going to see another wave of it, because I don’t think a safe and effective vaccine is going to be widely accessible by the coming end of the year.

Emma Ross

Can I just get in there on something you said that I think may – I’d like to see how the two of you see this differently, or the same, and that is whether containment is a lost cause. David seemed to be intimating, maybe I read you wrong, David, that containment is not necessarily a lost cause, if done properly. First of all, Gabriel, do you think containment is still a possibility, or should we just move on from that now?

Professor Gabriel M. Leung

Well, I don’t think that – I don’t think we have – we’re at the stage of containment anymore. By containment, I interpret it to mean that, alright, this is really trying to completely eliminate it from human circulation. That’s how you contain something, and drive it back into the wild, like SARS. We’re dealing with a completely different bug, although it’s got a very similar sounding name, SARS-COVID-2, as opposed to SARS-COVID. I don’t think the characteristics of this bug allow us to contain it and therefore eliminate it, and certainly not eradicate it. I think that we’re looking towards a transition to endemicity, that is it will keep circulating, but with slightly lower amplitudes every time it comes through and certainly, initially, before vaccines become available, it will be because of behavioural changes, either the individual or the population level, and then given a slight kick by seasonal forces. But if we actually get either permanently neutralising vaccine, or at least a transitly neutralising vaccine, then that will change the dynamics a lot. That would dampen the perturbation to that, sort of, sign wave. But I’m not sure at all that this is containable, as in that we would be able to eliminate it from any human population for any length of time. Remember that barely a week or two ago, New Zealand declared it being, or having been eliminated from its soil. Now, it’s got a handful of cases and I think that you’re going to continue seeing that sort of pattern. Beijing is another example and so, I think that, you know, I may be the – I maybe an optimist, but I’m one who worries a lot.

Emma Ross

David, containment.

Professor David Heymann CBE

Yeah, containment. To me, containment is keeping the level at a low level, so that the reproductive number remains under one, and that’s what countries are doing. They’re stopping outbreaks when they can stop them, they’re interrupting transmission, as they’re trying to do now in Beijing again, in order that transmission doesn’t begin in new chains from people who have been contacts and go into the community, those chains of transmission go in the community. So, I’m not talking about eradication, I’m not talking about elimination or eradication, I’m talking about containment. Stopping, where possible, because the epidemiology of this virus says that some outbreaks can be contained, not fully contained possibly, but contained enough to keep the reproductive number lower than one and to keep that increase in cases from occurring. So, hopefully, that will be what happens.

But I will agree with Gabriel, and I always have, that this could become endemic. That’s what the fear was with SARS as well, and if you look at coronaviruses, there are four coronaviruses, as you know, which are endemic in human populations, and we don’t know when they entered populations, human populations. We know when they were first identified and that’s been since the 1960s, but these viruses likely entered the same way as this coronavirus has entered, and in many instances, it may have been a virulent virus, which, over time, became attenuated because of mutations as it reproduced, or some other factors, which made it more able to become endemic and transmit regularly during seasonality. So, I’m not saying that this virus won’t become endemic, if it follows the pathway of four other coronaviruses, it would become endemic eventually and, hopefully, at a lower level, but we can do a lot to contain it now.

We can also make sure that we shield our elderly populations and that those people who have co-morbidities are shielded as well, and they understand, so that everybody, no matter whether they have co-morbidities or not, can do their own risk assessment and, with the knowledge that governments has provided them, contribute to containing the spread of this outbreak. So, we – I believe we can contain it in some countries. Some countries can avoid a second wave, other countries will, of course, not be able to. So, I think Gabriel and I, as much as I like to tease back and forth, I think we both are on the same pathway and we both understand enough about epidemiology to know that we can’t make great predictions, but we can predict using evidence that we have today. So, I’m going to turn it back to Gabriel, maybe through you, Emma, do you have some other things to raise?

Emma Ross

Well, there was something actually that Gabriel said, “Due to the characteristics of this virus,” I wanted to ask which characteristics, and something in particular about whether, given what we know now about the virus, especially this pre-symptomatic transmission, do you think it was ever a possibility, even if everyone acted quicker and did everything perfectly, that we would have been able to stamp this out, eliminate, given that – how do you – especially if your testing is based on going after suspected cases, if there are no flags being raised by a pre-symptomatic, how are you going to find where the virus is? Would we ever have been able to eliminate this, even if we had done everything perfectly and all the mistakes that have been made, whatever those are, weren’t made? David, why don’t you start on do you think it ever would have been possible, given what we know now about the virus characteristics?

Professor David Heymann CBE

Early on, WHO thought that it might be possible. That was before it was understood how the virus transmits, this current virus transmits, and where it reproduces. We know now that SARS coronavirus reproduces low in the respiratory system, this is the one that caused the SARS outbreak in 2003, and didn’t spread as easily, it seems, as does this virus, which is growing in the upper part of the respiratory system and which is very easily to spread in droplets, just by common talking, it appears, or by singing, such as in the choir in the State of Washington, where 87% of people in that choir, that was rehearsing for two hours, became ill because one person – became infected because one person was ill. So, we know a lot about how this transmits in confined spaces and it transmits through the air, and it transmits, I believe Gabriel would know, but Gabriel has more experience with SARS, in an easier way than does SARS. So, I’ll turn back to Gabriel and let him continue with the discussion.

Professor Gabriel M. Leung

No, I think I – I think David has really, you know, highlighted the important points, but I think pre-symptomatic transmission is one major reason why I don’t think that it would have been containable or – at any time that we could have eliminated it, or eradicated it. I don’t think it was ever possible. Number one is because of the pre-symptomatic fraction being up to 40% or so, which is what we actually documented, as early as a couple of months ago now, and it’s been repeated many times in many other settings. Second reason is coronaviruses, at least the newly emergent coronaviruses in the last 20 years, SARS, MERS, and now COVID-19, they have been demonstrated to cluster and if you, sort of, take clustering to the, sort of, extreme, then you get super spreading, in that somewhere between ten to 20% of index cases cause 80% of the entire caseload. Which tells you that really, the potentially explosive nature of spread is concentrated in a very small number of people and therefore, unless you have some way of identifying them quickly, because they spread pre-symptomatically, up to 40% of them, there is absolutely no way you could actually stop the spreading. And therefore, that’s why I don’t think that it would ever have been possible to drive it back into the wild, once it has entered the human population, and that really goes back to my previous point about how David and I, perhaps differently, interpret the term ‘containment’. So, the substance of what David said, I completely agree with, I just call it suppression. So, you keep the numbers to a minimum, but you are not going to be able to actually drive it back into the wild, I’m afraid.

Emma Ross

Okay. I wanted to pick up on the experience with SARS and – but how precisely has the SARS legacy helped these countries respond better? So, how has it informed the responses and influenced the outcomes you’re getting precisely? We’ve heard a lot about experience with SARS has shaped the responses, but how has it benefitted these countries this time round?

Professor Gabriel M. Leung

Well, let me just have a shot at it first, seeing that I live in a SARS affected place, although David actually spent a lot of time out East during the time of SARS, of course, on behalf of the WHO. I think it’s really the sociological imprinting, the indelible imprint of that experience, of what a major outbreak could do socially and economically, besides to the health sector. And I think just about every place that went through SARS had an entirely new, or renewed, public health function for health protection, as a result. Every responsible senior officer in every affected place were replaced. Every agency were transformed and the population really lived through the deserted streets, the deserted airports, and really lived through a huge dip in the economy. So, I think that’s something that you’ve got to have gone through, through experiential learning, and that’s how I would say really marked the SARS or MERS experienced countries out from the rest of the world. And I bet you that, indeed, you are going to see a very different post-COVID-19 world, not only in the health sector, but generally writ large in the broader economy, as well as in social interactions.

Emma Ross

Because of the personal experience with it, rather than having to learn from another country?

Professor Gabriel M. Leung

Because you know what an outbreak can and has done.

Emma Ross

David, what are your thoughts on legacy of SARS and the specific things that would have informed the response, or what makes the experience different there?

Professor David Heymann CBE

Well, you know, Emma, in Europe, the lockdowns were really a panic measure taken because of fear that hospitals would be overwhelmed and not able to deal with patients. I know that in Hong Kong and in South Korea, and also in Singapore, after the SARS and MERS coronavirus outbreaks, there was an attempt to shore up hospitals, to build resilience into hospitals, so that they could then deal with an excess of patients. I know in Singapore, for example, there’s a 300 bed unit, which has been developed just to take care of people who might have a SARS-like illness, and they’ve used that in this coronavirus outbreak, and that provides in each room, facility for ventilation and also for renal dialysis. An incredible advance in making sure that there is the resilience and the surge capacity necessary to deal with an outbreak such as this. And that came because of the importance of the SARS outbreak in that country, and, not only that, but the lessons that were learned were then translated into action.

Many countries in Europe and in North America had simulation exercises, which took them through very similar situations to a SARS coronavirus outbreak, and the lessons were learned, and the lessons were learned and put on paper, but they were never translated into action, as they were in Asia. So, I think Asia had that added value, as Gabriel has said, in having had the personal experience of that outbreak, which was really a terrible experience for many people, for most people in those areas. So, I think that learning from the lessons, either from a simulation exercise or from reality, must in the future, translate into action. It did in Asia, it didn’t in many other countries.

Emma Ross

And do you share Gabriel’s sense that because the rest of the world now has first-hand experience that our level of preparedness or resilience building will be different this time, rather than learning from an outbreak far away?

Professor David Heymann CBE

One would hope so. One would hope that we have learned from this very difficult lesson, but time will tell. You know, sometimes institutional memory is very short, especially if there’s a political leadership to the response and not a public health grounded response. Many countries have had a more political response than a public health response, and therefore, the public health agencies in many countries have been marginalised, in some instances. In my own country, in the US, the Center for Disease Control has been marginalised, while the reaction and the activities are being done by states because there’s no strong leadership, federally, in how to deal with this outbreak. So, it just depends on what the politics are in a country, and whether the Politicians have learned and will translate those lessons into action, as they did in the SARS and MERS coronavirus affected countries.

Emma Ross

Gabriel, have you got anything to add about this? What about the level of compliance and trust in government in the countries that experienced SARS? Was that of a slightly different flavour than what we see elsewhere, and how important might that have been?

Professor Gabriel M. Leung

Well, I think, of course, you know, for any country, trust in government, trust in science, or Scientists, trust in professional advice is what you would hope for and rely on, especially going into this kind of pandemic, which is something that we have not seen, at the global level, for a century. So, yes, that is what you would want, and, you know, it’s almost motherhood and apple pie, to draw that inference to say, look, you know, there is a positive and direct relationship between the two, trust in government, trust in science, trust in professional advice, and pandemic outcomes. But I also draw your attention to my home, Hong Kong, which went through six months of very, very serious social unrest last year. So, we actually went into COVID-19 with trust in government being at the lowest in decades, possibly ever, and therefore, it’s not a direct correlation, and whether you can draw that proportionality between trust in the authorities and pandemic outcomes. And so, that’s at least in Hong Kong’s situation, perhaps we’re the exception, perhaps it’s also because we’ve all lived through, whether you work for government or whether you are just a Hong Konger, as part of the general public, we all lived through the memory of SARS, and therefore, responded perhaps not because of the trust, but despite the deep social divide and sometimes even mistrust, that we have been very lucky and that we’ve acted, as a population, to protect ourselves.

You know, we’ve had just over 1,100 cases, confirmed cases, and we – and out testing, on a per capita basis, is amongst the best in the world, and four deaths. So, I think that, you know, that’s also perhaps an interesting case study.

Emma Ross

Sorry, thank you. I wanted to ask you about – regarding where we go from here. I’ve heard you frame the dilemma, in response to this pandemic as a three-way tug of war between health protection, economic preservation and social acceptance. Can you talk a bit about what you mean and what that means for responses going forward?

Professor Gabriel M. Leung

So, I mean, we’ve already seen all three and I’ll give you examples to illustrate what these three forces are. Health protection, I don’t think we need to really belabour, everybody understands that. It’s about saving lives, it’s about making sure that people don’t develop serious complications, which can have long-term sequelae. It’s about making sure that we do not exceed the search capacity of the health system, particularly ICUs and hospital beds, such that basically, the whole system would implode because of that weight of the care burden.

Economic preservation, we are looking at the deepest recession since the Great Depression and so, how do we get out of – not just looking at GDP figures, but also, I think, much more pertinently, to livelihood is unemployment and underemployment. So, I don’t know of any country anywhere in the world that hasn’t recorded the worst numbers for several decades. And then, social acceptance, you know, you have seen it, you have seen it in terms of people’s unwillingness in some countries, or within some regions in some countries, to go with the drastic substantial physical distancing measures. You have seen people, including political leaders, who refuse to don personal protective equipment, including facemasks, and in extremists, I suppose, you – we all still recall the very vivid picture of a band of libertarians, I suppose you could call them, protesting with AK47s in a particular steakhouse, against physical distancing measures. So, I think that, you know, we do need to make sure that there is this implied social consent and that maintenance of the social contract, because your pandemic intervention efforts are only going to be as successful as they can be executed and complied with. So, that’s why I refer to the three-way tug of war, and I think it’s getting more and more difficult and the tension is getting tighter and tighter all around the world.

Emma Ross

David, any – what are your thoughts on this? Do you see it the same way?

Professor David Heymann CBE

I see it exactly the same way, and, you know, it’s always been a very difficult decision for medical people to make when it comes to saving lives or to not saving lives, because all the medical profession takes an oath that they will save lives. So, the future debate on this, which is – which has to take into account the inequalities that have been increased because of this outbreak in many countries, and the people who have died who have not in any way been associated with COVID, but couldn’t make it to a health facility because it was closed to them, these will all have to be taken into a balance when governments make the next decisions on their way forward. And it’s something that the medical profession itself will be mostly ineffective in dealing with, because our mission is to save lives. But it will be something that has to be discussed by the medical Economists and by a whole group of people, who will have to make some very, very difficult decisions.

You know, the way forward is clearly shelter those who are at greatest risk and make sure that that’s an impossible barrier between them and the rest of the people, so that the virus cannot get to them. That’s possible, it’s feasible, and it must be done. And we must then see how we can move ahead with our outbreak containment, or our suppression activities to make sure that the virus doesn’t overcome communities again, or overwhelm communities again, and hospitals, and then deal with these other issues, which are very difficult issues. Will an economy be willing to lockdown again? It’s not clear. Some may be, some may not be, and, you know, it’s important, as industry and as small businesses and as schools and other sectors begin to work again, that we make sure that we’re doing what we can to make sure that those don’t become areas that have to be shutdown again.

Emma Ross

Thank you. I’m going to move to questions now, starting with an upvoted question from Trisha de Borchgrave, “Would David and Gabriel recommend mandatory wearing of facemasks everywhere, not just on public transport, particularly with pressure now on bringing safe distancing down from two metres to one metre?” David, since you’re smiling, I’m going to pick on you first, why don’t you answer.

Professor David Heymann CBE

Okay, well, masks have been a very, very difficult issue to deal with in many countries, and I’ll just go over again what the recommendations are, and based on the evidence that WHO has been able to pull together, and that evidence is that masks should not be worn as a personal protection. There are two reasons for that. One is because virus can, in fact, sometimes make its way around a mask and into the nose or mouth and infect people. And the second reason is that the eyes remain exposed and the eyes are also an entry point for droplets that are infected with the virus. So, masks should not be worn and give a false impression that people are protecting themselves. What they need to do is physically distance, and that’s a controversial issue.

WHO recommends physical distancing must be one metre or greater, based on the evidence that they have; countries then interpret this and make their own rules. But physical distancing is the most important and it’s also important that good personal hygiene be followed and cough etiquette. So if you do cough, you sneeze into your arm, or you cough into your arm, and if you can wash your hands, you should wash your hands, because surfaces theoretically, can be contaminated with droplets from someone who’s talked, spoken or sneezed and that can then infect somebody if you touch your nose, eyes or mouth. So, hand washing and physical distancing for personal protection.

We can also use masks – we can use masks to protect others. Hospital workers use them in combination with PPE, personal protective equipment, to protect themselves. People, however, can protect others by wearing a mask that catches their droplets if they should speak, cough or sneeze. Those droplets are then caught with it – caught within the mask and don’t spread onto others. And there is evidence that people who are pre-symptomatic, who don’t have signs and symptoms, can transmit this infection. So, that’s the reason that wearing a mask will protect others, if everybody’s wearing a mask. So, if you’re on the Tube, for example, in London, and everybody is wearing a mask and wears it properly and doesn’t remove it, there’s a good possibility that everybody is protected on that Tube, if someone is there with an infection. So, masks have a role to play in protecting others in closed areas, but also, in areas such as nursing homes and places, even where there are elderly in the household, where you can’t physically distance, but must be closer to a person who’s infected.

So, that’s what WHO recommends, that’s the logical recommendations, and if people understand that, they can do a lot to do their own risk assessment and protect themselves and, at the same time, protect others. Gabriel?

Professor Gabriel M. Leung

I think that – look, I agree with, you know, what David has said. Let me just add that I think, first of all, there are cultural differences in social acceptance of mask wearing and that certainly came through since the time of SARS really, and that we must take into account. Second, I’m not sure that I would make facemask wearing mandatory, because it can create another new dimension of inequality, because facemasks are – could be in short supply and, in fact, are likely to be in short supply in many countries and therefore, when anything is in short supply, prices tend to go up. If you make it mandatory, then you have to deal with, in addition to compliance or social acceptance, you also have to deal with how you make it affordable, so that you do not then create another layer of inequality and restrict people’s liberties any further than you necessarily must.

And, third, our experience in Hong Kong clearly shows now mask wearing is, in public places, is 97/98% and that they have been, since early February, but we still experienced a fairly significant wave during three weeks in March, when physical distancing measures were, sort of, temporarily relaxed or lifted. And, therefore, the experience that we’ve drawn from that, in addition to some experimental work that we had done previously with human coronaviruses that are seasonal, not COVID in particular, show us that masks are probably a good idea, or maybe even necessary in public places, certainly in a crowded place like Hong Kong, but they’re insufficient. So, a mask is not some sort of invincibility cloak, it is just one of many different kinds of measures, behavioural and physical, to protect us. And I absolutely agree with David that actually, the mask wearing protects others more than they protect us, so it’s really a sign of respect towards others around you that you wear a mask, and it would only work if it is reciprocated by a substantial proportion of the population.

Emma Ross

Thank you. I’m going to go to another upvoted question. This is from Charles Clift, “Some countries, particularly in Asia, Australasia, have used travel restrictions, quarantine, travel quarantine effectively to suppress the virus, and some not, yet WHO sees only a very limited role for such restrictions early in an epidemic. Should WHO review its position on travel and trade in the light of the COVID-19 experience?” Gabriel, do you want to start with that one?

Professor Gabriel M. Leung

I think that there are generally three categories of interventions that is available to the authorities to control the outbreak. One is border restrictions, two is quarantine isolation that are underpinned by test and trace, and three is physical distancing of one sort to another, whether it’s a school suspension, or complete lockdown. So, these three control knobs or dials need to be operated in sync with each other. So, if you are thinking of lifting some of the border restrictions, in terms of travel, whether it’s looking at immunity passports, or whether it’s lifting of the travel restrictions by creating travel bubbles or corridors, then what you really should do is hold the other two quite firmly and perhaps even ramp one or more of those things up, so as to compensate for lifting on the travel restrictions. So, that’s why I think that you need to take a look at the whole picture as opposed to just saying, or labelling, any particular intervention as being the main driver or determinant of whether you are going to have a locally sustained outbreak. And, in Hong Kong, we’re about to lift some of the travel restrictions and we are in proactive negotiations with some partner countries and places and ports to create these green corridors and therefore, we have maintained many of our physical distancing measures, while lifting some others, and also still yet trying to perfect our test and trace capacity.

Emma Ross

David, do you have any thoughts as to whether WHO might need to look at the way it looks at travel restrictions and recommendations for travel?

Professor David Heymann CBE

I think Gabriel has just talked about the importance of a risk assessment, based on what’s going on in a geographic area, or in a country. He’s talked about how you change the dials and make your decisions, and that’s what really has to be done today and can be done today, because of the flow of information from countries, much of it through WHO, from WHO itself, and from publications that are actually available to everybody in front of the paywall, in many of the medical journals. So, people have access to material that they can use to do their own risk assessments and countries, in particular, do use this to do their risk assessments. This was not true in 1969, when WHO was asked, in the International Health Regulations, to make a determination of whether it was safe to travel, based on what they knew from four different diseases and from reporting by countries, that was the only way WHO was able to find out what was going on, because we didn’t have the electronic highway that we have today. So, they were finding out this information from countries and they were making a recommendation, legitimately, to all countries, here’s what our risk assessment shows, here’s what you should be doing.

Now, we’re in the 21st Century, where there’s much, much more information available to everyone, and this recommendation needs to be and will be looked at again by WHO, because it’s a hold over from 1969, when WHO had access to most of the information, and there is a reason that it should be re-examined and maybe modified. But that doesn’t – two things, after I’ve said that is, number one, it doesn’t replace the need for WHO to talk about the need for travel for humanitarian purposes and to make recommendations on that, and also, on essential trade, if trade has been blocked. So, WHO could still play a role in this, and must play a role in at least those two areas.

Gabriel talked about green corridors, and this is really what it’s all about, as we exit from lockdown strategies, and that’s what I like to call, and what WHO calls, equalisation of the risk and equalisation of the response capacity. And when Hong Kong is looking at where they might be able to be in travel and transport, I know they’re looking at those two issues, can this country – is this country have reliable figures about what their transmission is, and does this country have in place a mechanism to detect imports or exports and also, so to clamp down on those with what I call a containment activity, with what Gabriel calls a suppression activity, to make sure that they can stop those? And this is what it will be about in the future, creating capacity to deal with outbreaks as they occur and to suppress and at the same time, to keep that level of transmission low.

So, back to the issues of travel and trade, travel and trade will only open up, not when WHO says it should, because that’s not the way countries are doing it today, it’s when countries feel their risks have equalised with other countries and they can take the possibility of increasing travel and trade. Gabriel, do you have anything more to say to that?

Professor Gabriel M. Leung

No, I think that, of course, just going back to the balance, or the tug of war with economic preservation and social acceptance, I think that these green corridors, or travel bubbles, are, in large part, driven by those two other considerations and it’s not just about money or the economy. It is really about, you know, how long can you ask people to live under lockdown conditions and not travel at all? I mean, even if you allow, sort of, business and trade to go ahead, I think that the so-called leisure travel, while I wouldn’t quite recommend it just yet, for many, many countries, but I don’t think that it would be reasonable to, sort of, extend this kind of new normal for a year or a year and a half, depending on when we actually have a safe and effective vaccine.

Emma Ross

Thank you. Another question, and most upvoted, Nahida Porter-Carrero, “Why are test and trace being bundled so tightly together? There are many in the UK who would be happy to be tested, if tests were available to the public, but would be reluctant to be involved in contact tracing. Surely, testing, independent contact tracing should be made available and would be useful.” What are your views about that? Gabriel, do you want to go first on that?

Professor Gabriel M. Leung

Test and trace are inseparable, for the simple reason that unless you extrapolate testing towards infinity, that is, I suppose, the safest thing theoretically, would be you’d test everybody every five days. That’s actually what would be required, if you want to get rid of tracing. But that is not possible, nor desirable, quite honestly. So, test and trace is inseparable because you can only test if you are able to trace the contacts of a confirmed individual and then you can go and test them. But if you have no way of tracing, and that is identifying who these high risk or exposed people may be, you can’t test them. So, that’s why they’re inseparable, and I think that it is something that we must do better and I really don’t think that people particularly object to being traced and, in fact, they might appreciate it, if they indeed might have caught the virus. But I think what people may be more sensitive to is really the intrusion into privacy, confidentiality, and how discretely tracing is done and how professionally it is done. So, I think that we need to impress upon the authorities that these are the things that the people care most about, and most people would be very happy to oblige with these public health interventions, but we also need to think about the ethical, personal, legal and social issues, and these are not trivial. Most times, when we have pandemics, or large outbreaks, whether it’s COVID-19, or Ebola, it’s actually sociological challenges that lead us astray and actually hamper the control of the outbreak.

Emma Ross

Thank you. We’re coming close to the end now, we have time to squeeze in a quick answer, if you could, so I’m going to pick a question that hopefully can have a quick answer, almost yes or no. This is from Prasad Rao from The Atlantic, and it’s also an upvoted question, “Are the renewed restrictions in Beijing, the closure of schools, cancellation of flights, a reasonable set of restrictions, given what we know about renewed infections there, or an overreaction? Should those living elsewhere prepare ourselves for such renewed restrictions?” So, hopefully, we can quickly, in two minutes, handle that. David, do you want to go first?

Professor David Heymann CBE

Well, you know, China has done what they’ve done in the lockdown, based on their risk assessment and yesterday, at WHO, there was an excellent presentation by the Chinese Center for Disease Control, of what they’re doing and why they’re doing it. And they have justification for why they’ve locked down in certain sectors, and it’s only been in, as Gabriel said, in the periphery around where this market is occurring and they’ve traced some of the contacts to other places. They know what’s going on, they have an epidemiological sense, and they’re approaching this in an epidemiological way to suppress any further transmission, if they can. This is what it’s all about, countries implement this in different ways, but in the end, it’s all about a local risk assessment and a local response, and it’s the same with contact tracing. If communities aren’t involved in the contact tracing, if they’re not doing it, where there’s trust among people, then it will not succeed. It has to be done in an area where there’s trust of the people„ and it’s been done for sexually transmitted infections, it’s been done for TB, and it keeps disease at a low level, which is what is attempted to be done with this outbreak. Gabriel?

Emma Ross

Thank you. Gabriel, overreaction or reasonable? Quickly, one minute to go.

Professor Gabriel M. Leung

Contextual, look at the context. I think that we need to bear in mind, and whether it’s reasonable or an overshoot or whether it’s an under call, all depends on the context. I think epidemiologically, it can be justified. I’m not sure that the same reaction, or the same policy would have been implemented, in a very different setting, but I do think that this is the right call for that particular context.

Emma Ross

Thank you, and we’ve come to the end now, because both David and Gabriel have other things they have to go to, pretty much on the dot. So, I wanted to thank you, Gabriel, for joining us, for a really great conversation, and thank you, David, as always, and thank you all for tuning in.