Interview with Professor Gabriel Leung,
Dean, Faculty of Medicine,
University of Hong Kong
on the outbreak of COVID-19
March 5, 2020
This is a rush transcript; an audio recording is available here
James Chau
This is The China Current. I'm James Chau. There is not one word that captures Gabriel Leung, an epidemiologist who was instrumental in the SARS response, a former Under Secretary for Food and Health in Hong Kong, current Dean of the Faculty of Medicine at the University of Hong Kong, and a member of the ongoing WHO joint mission for COVID-9. He is critical to multiple levels of the response, as the outbreak that centred in Wuhan now seeps its way to almost every part of the planet. The story, like the virus, is new, fast-moving, and changing. So I called him to unpack the nuances, to help us better understand, better prepare, and better act.
Gabriel, I want to start off with what you said the other day you said the whole point of epidemic control is to flatten the peak, so that in your words, societies and hospitals don't get overwhelmed. So, the first question is an obvious one: has the peak flattened?
Professor Gabriel Leung
So in mainland China, the first wave is all but over. And that is because of the whole-of-government, in fact, all-of-society response for the entire country. So with the possible exception of Wuhan, and neighbouring municipalities in Hubei, the rest of the country you have seen a dramatic reduction in the daily reported new cases. And from our analysis, looking at transmissibility, the force of infection in the community is very, very much reduced because of that response. I think what we should now be alert to, as well as really very closely monitor, is that as economic activities resume, albeit gradually and in a deliberate manner, then you should be very closely watching for any first signs of recrudescence. That is, is there going to be a second wave as the rest of society goes back to normal functioning. And even if there is going to be a bit of a second wave, that is only to be anticipated, and so long as it remains under control, where let's say the effective reproductive number - that is the average number of secondary cases that a typically infectious individual would transmit on to - so long as that number remains steady at below the unity value of one, then the rest of society as well as the health system can cope. Now that's for [mainland] China.
For Hong Kong, we have been doing a lot of social distancing, as well as personal behavioural changes. Everybody has a mask on especially when they go outside. People have really cut back on going to work, flexi working hours, flexi working days, home offices, schools remain suspended, and nobody's really going out to shopping malls, or for large gatherings or even meals socially. So all that has kept our numbers relatively stable and the effective reproductive number is just under one in Hong Kong, which means that it's not eliminated, it's not going away. But it's on a very slow and steady course. And that's really what you see in Hong Kong and in many ways also mirrored in Singapore. We just need to keep being vigilant and continue with our containment policy.
As for the rest of the world, you are now beginning to see the beginnings of the first wave that mainland China went through a month ago. The rest of the world, in particular some countries where you've seen explosive growth of the outbreak, like South Korea, Iran, Italy, and unfortunately probably also the United States because the number of deaths that's been reported so far is what is more worrying than the absolute number of new cases that's been diagnosed. But that is really an artefact of not having been testing enough in the earlier part of the response. So that's really what the global picture is at the moment.
James Chau
You talk about behaviours. What about discipline? And is there such a thing as outbreak fatigue, as this outbreak in mainland China and increasingly around the world continues down the timescale?
Professor Gabriel Leung
Of course, you can't keep on suspending work, school and all societal functions, effectively closing down for an indefinite period of time. That is not sustainable, nor is it advisable. So the big question is, given the success of the China response for its first wave, which or are the determining components of that response that can and should be adapted, and modified, and then replicated in other countries? I think it would be silly to try and completely do a copy and paste. That is not possible, and that is not feasible, nor pragmatic. But I think it is absolutely critical that we look at the whole package of interventions that China has been implementing, then work out which of the component parts are the main drivers of that huge dramatic reduction in the force of infection, and therefore, then isolate those components and then see how they might be adapted to other countries.
James Chau
Let's tap into another area of your work, which is, of course, the science. What do we know more about the epidemiology, because understanding that surely is going to unlock all possibilities into the future?
Professor Gabriel Leung
I just finished co-chairing the epidemiology track of the WHO R&D roadmap for COVID-19, just a few days ago, and there are really four areas. One is transmissibility, which we've talked a lot about to severity, and the flip side of that is susceptibility, and then the last bit is really an assessment of the measures - that is, the interventions. So, we've talked about the transmissibility, we've talked about the assessment of the impact of those interventions - so onto severity and susceptibility.
Let's take severity. Simply dividing the total number of deaths by the total number of confirmed new cases as reported, at any single point in time in an expanding epidemic, is going to lead you to the wrong answer. It's wrong because it takes about two to three weeks, as best as we can tell, in order to have resolution of what may happen to somebody who is infected. Resolution in terms of, is this person going to survive and recover? Or is this person going to die of infection? So, simply taking a denominator of confirmed new cases who haven't had time to, quote unquote, resolve that clinical outcome, and then using that as the denominator, is not going to give you the right answer. It requires careful statistical or mathematical adjustment, and the answer is probably going to be closer to 1.4% - and that would be the case fatality ratio amongst all symptomatic cases. What we don't know yet is how large the completely asymptomatic portion of that clinical iceberg is. So, again, the second thing that we need to watch out for whenever a number gets thrown about is, what is the what is the denominator population you're talking about?
Generally, there are three levels. One is amongst everybody who's infected, and in order to have a reasonable estimate of the total number of infected, you would need to have good age stratified serological studies. These are being rolled out in mainland China, but the field work has not been completed yet. So we don't anticipate that we will have an answer for a few weeks. Then the next level up is symptomatics, and those are fairly easy to identify so long as they don't exceed your surge capacity for testing in your labs. And then the third level would be everybody who was hospitalized, who's sick enough to be hospitalized. So clearly, when you go up from one level to another, you will get a higher and higher case fatality risk. And that's what we're talking about with severity.
Finally, susceptibility goes to the very important question, for example, should we close schools? Mainland China, Hong Kong, Japan, and then, as of yesterday, Italy, have all closed schools. In the UK, especially some of the independent schools, have voluntarily and quite deliberately chosen to close or suspend classes, because they've had very close contacts with confirmed cases. The big question is, are children really susceptible? Because if you look at the reported case numbers, children seem to be relatively spared. But does it mean that they are not susceptible? Or does it mean that they are equally susceptible, but they don't present as very ill patients and therefore, they're being missed? Or if they are susceptible, then are they infective? That is do they go on to infect others? Do they spread it to others, like in flu? Children are a very important group of that transmission matrix. If they are, like flu, infective or even particularly infective, then closing schools will be the right thing to do?
James Chau
So, should parents be concerned, Gabriel?
Professor Gabriel Leung
Until you get good age stratified serology, you're not going to get that answer.
James Chau
I want to ask you also about the denominator, you said that we need to re-think the denominator. Does that therefore indicate that we need to re-think other approaches to how we are calculating?
Professor Gabriel Leung
The approaches out there, but it's just that because it is such an important number, we are fighting an infodemic as well as an epidemic. You get a lot of almost off the cuff bordering on cavalier comments on, oh the CFR is this, the CFR is that, without really explaining the context. And without that context, the number is meaningless. It either generates additional public panic, or it puts people in a place of complacency, neither of which are desirable as we go through this very difficult time for the entire world.
James Chau
How much does that panic and anxiety, and unhelpful comments as you put it, distract from the work of science - which has to be the underpinning work of any outbreak?
Professor Gabriel Leung
As of late, and by that I mean in the last couple of election cycles in most of, let's say, even just the liberal democracies of the world, but really globally, we have seen an apparent repudiation of science, of experts, of common sense really. And this wave of populism bordering on nativism, that outright rejects science and reason, is never helpful as the world now fights this global outbreak.
James Chau
You've long been a critical asset to organizations like WHO, but particularly in this ongoing and current response. You were obviously a contributor to the science and R&D meeting that happened a couple of weeks ago. And going forward, more recently, you've been an integral part of the joint mission over in mainland China. What can you share from that particular mission?
Professor Gabriel Leung
I think that I've learned such a huge amount, first and foremost, the co-leads of that mission were absolutely inspirational figures. So Bruce Aylward from the WHO, and Dr. Liang Wannian from the Chinese ministry, or the National Health Commission. Both are very well known, well acknowledged veterans of fighting outbreaks. I as well as others have learned so much from them and been inspired by them. But I can only speak for myself: I think that whatever little that I may have been able to contribute to that process, which is a very thorough week-long process, preceded by a sentinel team that went before us to prepare the way and followed by the publication of the bilingual report. I think that the whole process has been very rigorous, very robust. And I think the report that has come out has
and will continue to help the global outbreak, and to inform what countries may consider doing arising from the new knowledge that has been gained as a result of that particular mission. In large part, based on the superb investigation that has been done by the Chinese authorities.
James Chau
There's been a lot of question around the capacity, and the willingness of the Chinese authorities to deliver on this outbreak. You've been asked about it many times, I'm sure. As someone who's been a part of it as a first-hand participant in this international joint mission, what do you say?
Professor Gabriel Leung
I would just echo what Bruce has said many, many times, most recently in the New York Times interview, that it is a very scientifically driven process informed by field exposures. Not only to hospitals, but also clinics, to wet markets, to different parts of the country, to the epicenter in Wuhan, as well as to the south, to the north, and really having a lot of input, looking at what the Chinese have done, and continue to do, and coming up with a report that has been endorsed by all 25 of us who were members of that commission.
James Chau
People seem to think that this is somehow the first time that China has worked with the world because it's a new outbreak. But of course, there's been a long-established scientific collaboration between international partners, not only WHO and Chinese CDC, for example, and the [National] Health Commission. Was that experience on the team a very free-flowing exchange?
Professor Gabriel Leung
Absolutely and it goes beyond the health sector. So, in each of the provinces that we visited, the provincial governor and all the relevant government departments, all came and all really pitched-in with supplying information, with showing us data, and providing access for us to ask questions. That's really been very helpful. I think that you do need a whole-of-government and a whole-of-society approach to fighting a global epidemic of this scale and speed.
James Chau
The backdrop behind you is a reminder of the many different areas in which you work. Of course, you're speaking from the University of Hong Kong, where you're the Dean of the Faculty of Medicine, you always have a political background as a former Under Secretary for Food and Health. You're a scientist. And you've been a big part of the global response on this. Where would you say to families and individuals, in countries are now experiencing the spread of the outbreak in countries maybe like Norway and Switzerland, but also Iran and Italy as you mentioned before... what would you advise them to do, both on the community level, but also on government level?
Professor Gabriel Leung
I think that the government level is easy. It's a whole-of-government approach, because it does take across the board action from making sure that finances work, that there is swift mobilization of the necessary funds, and people so that you could get the necessary resources to the places that need them - and quickly. In addition, you do need the home affairs department or the civil affairs Department to make sure that needs of society beyond health are well looked after, that come what may, you do need to have the rest of societal functions really working.
Of course, health is a very important and the central part of it, but you do need for example, if you are going to have temperature screening at the border, you need your immigration and customs departments all on board, you need your airlines to be adherent to infection control policies, you need your train stations to be on side. So a whole-of-government approach is really what is called for and absolutely necessary. As for civil society, the press, the media, they all have a role in making sure that voices are heard from every quarter of society. Because what I fear with this particular disease is that we may be at risk of committing, either by commission or omission, huge health inequity. If my fees are borne out, globally, the fatalities or the mortality rate or risk, is going to track quite closely with per capita availability of ventilators and ICU beds.
James Chau
Does that necessarily mean then that more fragile health systems are more at risk or not necessarily?
Professor Gabriel Leung
Oh, absolutely. Absolutely. If my worst fear is a holdout, then it would be a huge inequity. And we need to recognise that upfront and protect those who are most vulnerable. That's really for civil society, for the media, and for communities to really make sure that they provide that third voice, fourth voice, and fifth voice. Then for individuals, it's only right to be alert. It's understandable and only human to be anxious, but try to stay calm. Try to listen to voices of science and reason. Don't panic, whatever you do. And just be sensible with practising good hand hygiene, as well as try to make sure that you avoid large social gatherings, crowded places, and if you must go to these events, protect yourself and protect others. Put on the mask. Let's work together and get through this. It's going to be a difficult catch for the next several months is my guess. Hopefully, then we will start seeing some of the results of the drug trials, whether it's repurposed existing drugs, or new drugs. And hopefully we will continue to hear good progress on the vaccine front.
James Chau
I don't want to ask simplistic questions, but very briefly, you are one of the people who has to travel physically [because] you're part of the response in different ways. What precautions do you take when you travel? And for people who are worried about traveling right now, for their business, for their family, what do you say to them - and what do you do?
Professor Gabriel Leung
The first thing I say to anybody who asked me to go somewhere else is, must I? And then the second thing that I would do if I really have to travel is to make sure that I bring sufficient PPE [personal protective equipment], so that I do not impose on my hosts in providing them. Thirdly, while I'm en route, on board, or in a train carriage, or in a coach, make sure that I clean the seat that I sit in, because you can't expect aeroplane crew or cleaning staff to do complete disinfection with a very short turn-around time. Other than cleanliness, I make sure that I put on a mask when I go especially on long-haul flights. And make sure that I do good hand hygiene. When I get there, then I just live a normal life as I would back home, except of course to remind everybody around me as well as myself, that we must be universally cautious for respiratory droplet infections. If you take that with you, then you should be reasonably safe.
James Chau
I have to ask you since you've travelled, as you said on several long haul flights, once you reach the other destination, or in process on that journey, have you experienced yourself any of the xenophobia that people have been talking about, or more simply the stigma associated with this region right now?
Professor Gabriel Leung
I have not personally experienced it, but I have read reports and very real reports of such. All I can say is, this is not a Chinese disease, this is not a Korean disease, this is not an Italian disease, this is not an Iranian disease, this is not an American disease. This is a disease that is now sweeping the world and we're all in the same boat. Only with that sense of equity and solidarity, can we all get through this.
James Chau
Can you imagine, I don't think we even mentioned the word SARS once, which is, of course, your great specialty from the early 2000s. But I want to finish off with this, by looking ahead, not only to the next outbreak of a disease epidemic or pandemic, but looking ahead in general over at the University of Hong Kong, you'll be leading a special online course on epidemics later this month, we're in March 2020. What would you be imparting, based on the very rich experience that you've earned over these decades? What do you think will be essential for that next generation of leaders in outbreaks to take away with them?
Professor Gabriel Leung
It's actually a course that we've offered for, I think, five years now. So it's not a new course but we will have special modules on COVID-19. But every time that there is a worldwide outbreak... the last time we added an additional module on the West Africa Ebola outbreak. And at that time, we had several people Peter Piot being one of them filming that additional module. And this time, I have had the privilege of repaying his debt. I was actually in London at his school just last week, and he got me to do a special module for the London School MOOC, which, which I very happily did.
So yes, we very much look forward to this knowledge exchange, and really share it again in solidarity. What we will be covering and have always covered in that particular MOOC, are the basic building blocks of the epidemiology and the outbreak investigation. Hopefully that
would either just interest the lay-person who might be quarantined, or just trying to stay home with the home office arrangements, or for school children who are otherwise staying home because their schools have been suspended. So that might be something of general interest - or for some of the graduate students, who might actually find that this could be useful to formulating their graduate theses.
James Chau
So, we can all theoretically participate?
Professor Gabriel Leung
Of course, of course.
James Chau
This is an whole-of-Gabriel response to this. Peter Piot is a very special person who has contributed greatly to the world - as are you and as do you. Gabriel Leung, thank you very much.
Closing
The China Current continues its special coverage on the coronavirus outbreak. Go to our social media @TheChinaCurrent, and our website for interviews, videos, and podcasts. I'm James Chau. Thank you.
