Omicron in Hong Kong

Prof. Gabriel Leung, Dean of Medicine at the University of Hong Kong, joins Gavin and Jessamy to discuss Hong Kong's recent Omicron wave of COVID-19 and what this variant means for health systems and zero-COVID containment approaches.

You can continue the conversation with Jessamy and Gavin on Twitter by following them at @JessamyBagenal and @GavinCleaver.

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Transcript

Jessamy: Hello and welcome to The Lancet Voice. It’s April, 2022, and I’m Jessamy Bagenal. I’m here with my co-host Gavin Cleaver. Hong Kong and China, who have previously had relatively low case numbers of COVID-19, have recently experienced large waves. They’ve had high case fatalities despite relatively good vaccine coverage. We wanted to find out more and speak with Gabriel Leung, a physician and epidemiologist and Dean of Medicine at University of Hong Kong.

As always, find us on our Twitter handles, @jessamybagenal and @GavinCleaver, to carry on the conversation.

Gavin: Gabriel, thanks so much for joining us. Hong Kong has been in kind of a difficult position recently with COVID. At the start of March, it peaked with 900 infections per 100 000 residents. What are some of the factors underlying the current surge?

Gabriel: Well, the surge is actually now over. So we’re very much now on the tail of the fifth wave, which is omicron (BA.2), the most transmissible strain of COVID yet. Now I think that the, the surge was not unexpected because of the inherent enhanced transmissibility of the omicron (BA.2) strain. What was unanticipated by the authorities, I think, was the surge not only in incidence, but actually of mortality. And I think that was fundamentally driven by what was fully predictable and avoidable, low coverage of vaccination amongst the most vulnerable groups (ie, those who are 70 plus, as well as those who reside in nursing homes, elderly homes, and homes for the disabled). So that I think was our absolute Achilles heel, and that really was what accounted for the very high, unacceptably high, mortality. And this is in a place, like much of the Global North, with early, sustained, uninterrupted, and privileged access to two vaccines. So there, there was absolutely no reason why Hong Kong had to sustain that kind of mortality. So we’ve lost more than 8000 lives in a population of 7·4 million over the last couple of months.

Gavin: The narrative in places like the UK, where Jessamy and I are speaking from, where vaccination coverage is relatively high, is all about how omicron is more mild than the previous strains of COVID. But the evidence from Hong Kong seems to suggest that actually the vaccination coverage is still extraordinarily important with talking about the fatality rate that you’re mentioning there.

Gabriel: The vaccination coverage generally for the population was actually fine. It was 75% at two doses for the population as a whole going into the omicron wave. So, and now the overall coverage is actually already 86% with two doses. All right? So the overall coverage is actually not low by comparison. What was particularly low was actually those in the most vulnerable age groups. So that was the Achilles heel. It was the distribution of those doses. And secondly, omicron is actually not very mild, by any stretch of the imagination. It’s just mild compared to delta, which was the most severe COVID strain yet. So when you have just come off a delta wave and then you get omicron, that’s why it appeared to be much milder.

Now that’s number one. Number two is in much of the developed west, omicron came after a big sweep back in March, 2020, of the ancestral strain, even with the 614G variant, it was still the ancestral strain. And then it experienced alpha, and then there was a very large vaccination effort, and then came delta, and then there was booster, and then there was omicron. That was more or less what happened in temperate-zone, western, developed countries. All right? And that’s why, when omicron finally came along, a large proportion of the population would have already had hybrid immunity, some mixture of two or even three doses of vaccines, plus at least one episode of natural infection and recovery.

And so that’s the immune landscape of the population going into omicron, mostly going into (BA.1) first, all right? Which is very different from the Hong Kong immune landscape, which really had no natural infection and recovery to speak of. The cumulative incidence of COVID infection in Hong Kong up until the beginning of our most recent omicron wave was 1%. So 99% of the population had not been exposed to any natural infection yet. And then, when you go in and the only kind of immunisation that you’ve got was through inoculation by vaccines, not by natural infection and recovery. And in those very vulnerable age groups, it was very low.

So 70 plus age group going into the omicron wave, we were looking at 40–45%, not even 50% coverage at two doses in that age group. And for nursing homes, it was less than 20% coverage going into the omicron wave. All right? So that’s where the lethality became very, very apparent.

Gavin: We’ll get onto the lethality in a second because those are some really fascinating and striking stats. Do you think, from what you’re talking about there, that the omicron wave in Hong Kong offers some kind of insight as to the importance of natural immunity as well as vaccine-based immunity and a kind of hybrid protection, as you said?

Gabriel: Well, I wouldn’t say that the omicron wave illustrated that, all I would say is that omicron is not a mild strain. It is at least as severe as the ancestral strains, and perhaps alpha. It is mild and much milder than delta, both inherently because of its own intrinsic properties, but mostly because of the chronology of omicron.

Omicron came in the west after, as I said, at least three other variants, the ancestral strain, alpha, and delta. And in different places, you may have had some beta and some gamma as well. All right? Or instead. So, most of these places, unlike east Asia, including Australasia, which had mostly been sticking with an elimination strategy, the so-called zero-COVID strategy, up until fairly recently in the last 6 months. All right? So what had happened cumulatively, in terms of morbidity and mortality, in those parts of the world, which did not either by default or by design go for an elimination strategy, the difference was you had several waves of it already. So if you actually add all the morbidity and mortality numbers up cumulatively, then we’re not really out of the ordinary. It’s that we were really just part of this natural history. With the exception, and it’s an important exception, that is, we experienced it 2 years after COVID emerged, and 1 year fully into the vaccine era. So, that could have been much, much prevented and avoided.

Gavin: So it seems one of the key things, of course, that we’re talking about is the suboptimal vaccine coverage in the more vulnerable age groups. So what are some of the, what are some of the reasons behind that, especially that terrible figure that you’ve mentioned there of less than 20% in nursing homes? It seems almost unbelievable that, like you said, a year into the vaccine era that that would still be the case.

Gabriel: Yeah, and I think that it’s not because of the lack of good science, because everybody knew that these were the highest risk groups. In fact, our group was one of the first groups to have published on the severity, age-dependent severity of COVID, way back in February, March, 2020. So it’s not because we didn’t know about it, and it’s certainly not because we didn’t recommend it. In fact, these groups that had the lowest vaccine coverage were the prioritised groups from day 1.

So it was really, I think, a combination of risk comms and it’s not because of not enough information, but perhaps too much information about the early experience of the adverse events following immunisation, the so called AEFIs. And because almost paradoxically, because Hong Kong belongs to the Global North with very early access to vaccines, when you get these so-called adverse events that were reported, many of which were subsequently disproven to be caused by the vaccines, but because we had early access and that the risk-comms strategy that the authorities followed was, we will be as transparent as possible, we will not put any kind of qualification on it, and we just let people decide.

So that I think set up the initial impression in such a way that people were hesitant. And this is not a place that is usually vaccine hesitant, all right? But it was a place that had pursued very successfully a whole year of elimination strategy already, and it had another full year of essentially zero COVID, so people in their mental calculus, probably more than a few thought, well, why risk it when it’s not going to benefit me because there’s no COVID around? So I think that there was quite a lot of that as well. So it was a risk-comms strategy that was, well, if there is such a thing as being too transparent, it probably, this was one of the cases.

And so you will say, well, no, Hong Kong was not the only place that actually had, you know, the media play up the early adverse events. True, but most of the other places also had already experienced, back in the spring of 2020, a deadly, deadly wave, the first wave, as well as the alpha wave. So they knew what COVID could do and the risk calculus became very different for those populations. So I think it’s, it’s a bit of that.

Also, Hong Kong, for at least a substantial proportion of the population, also had very low trust in the authorities, because Hong Kong’s 2019 social unrest actually flowed right into the COVID pandemic. And so there wasn’t really time for society to heal these deep chasms. And we had one thing, one thing flowing into another; both were unprecedented in our history, right? So I think that played a part as well.

And also I think it’s more fundamentally, but perhaps not completely directly, related to the state of inadequacy of our nursing-home infrastructure and also the lack of a primary care network, both of which, of course, are essential to delivering public health goods like vaccines. And it just, you know, all these things coming together, it’s kind of like the perfect storm where, you know, lacking any one bit of it might have been fine, but when you actually hit all the buttons all lined up in a row with this never before seen for a century pandemic. That’s when things kind of go wrong.

Jessamy: Thanks, Gabriel. I mean, you’ve given a kind of brilliant summary of the story so far and the different waves and I just wondered whether we could focus on this sort of health-systems aspect of how the health system has been coping thus far and what the situation is, you know, on the ground with doctors, physicians, people working there.

Gabriel: Tough, tough. I think with any health system, when you have that kind of explosive outbreak, even though it is milder than delta, but Hong Kong never experienced any, well, Hong Kong never had a major delta wave. Hong Kong did have delta, in fact, from very clearly documented case of importation via pet hamsters, which actually was documented in The Lancet just last month.

So we do have a minor delta wave that actually flowed right into the omicron wave. But, you know, when you have this kind of explosive outbreak, no health system would be prepared for it because otherwise your health system would have had a lot of slack and no modern health system has that. I think where Hong Kong could have done better was to have had in place a solid mitigation plan, rather than just single-mindedly focused on being able to achieve elimination. So, I think that that’s where things could have gone better. And it also, the height of the omicron wave also coincided with the coldest 2 weeks of the year. So that made life a lot more difficult.

And then third, I think almost uniquely in Hong Kong, we have a relatively high proportion of the old old in institutional facilities (ie, nursing homes) compared to OECD countries, or many OECD countries anyway, but the space, the living areas of these nursing homes are, like much of Hong Kong living, very crowded. Which of course is exacerbated by the fact that 85, 90% of our homes in Hong Kong, nursing homes in Hong Kong, are privately provided, privately funded and privately provided, which are quite honestly suboptimal. So the 10, 15% of nursing-home places that are provided by NGOs that are subvented by government are much better. But because the vast majority are not those types, there wasn’t any space or hardware to cope with simple things like cohorting. And that’s why, I said, it basically revealed the underbelly of the systemic deficiencies. And if one had a very robust primary-care system that is properly funded by social means, either social insurance or government provided, that might have been able to make up for part of those deficits. But we don’t have that either. Primary care is very much a privately provided, fee-for-service type of system.

Jessamy: But just for listeners, your overall health system is tax-financed and free at the point of access. Is that, is that correct? But then the primary health care is, is separate?

Gabriel: Half of it. So for the hospital system, 90% of bed days take place in an NHS-like system. So tax-financed, publicly provided. For 90% plus bed days. And for some of the specialty ambulatory services. All right? But the vast majority of ambulatory services, particularly primary care, these are all 85% privately funded, privately provided, out-of-pocket fee for service.

Jessamy: That’s fascinating. And do you think that that’s a sort of a lesson or message that’s landed in this sort of political system as something that needs to be addressed or, or pushed forward? Or is that something that we’re, that you’re, you’re just kind of thinking about?

Gabriel: That’s, this is, this has been an apparent issue in many of the former or current Commonwealth countries in my part of the world, ranging from Sri Lanka to Malaysia to Singapore to Hong Kong. It is not a new problem, but I think that has laid bare, you know, what the potential consequences could be.

Jessamy: Yep. And so there may be movement on that, in the future?

Gabriel: You’ll have to ask our political masters that question.

Gavin: I wanted to ask actually, do you think the recent omicron wave has at all changed minds in Hong Kong as to pursuing a kind of rigorous zero-COVID policy?

Gabriel: I mean, we’re still officially pursuing the dynamic zero-COVID policy, and I think that the keyword is the dynamic bit. So the goal is to still hopefully try and clear towards elimination. But whether and how you go about it, I think that’s where the dynamic comes in and there’s more flexibility that way.

But I mean, I’ve, you know, for over a month now, you know, my team and I have actually modelled out the potential options for Hong Kong. When you talk about zero COVID, it makes a lot of sense before the wide availability of vaccines, it makes a lot of sense before availability of novel antivirals, and it makes a lot of sense when the R0 or the basic reproductive number was two and a half as opposed to seven, eight, nine. So, and I think that it makes a lot of sense in terms of the stage of your population, in terms of how much exposure it already has had. So there has not yet been a successful or useful example of zero COVID once the majority of your population has had natural infection and recovery. And by our estimation, about 60% of Hong Kong has already had omicron (BA.2) and recovered, save those 8000 tragic deaths. All right? So that’s why we need to really think our next steps in terms of how we go about it. I don’t really mind what you call it, because whatever you, whatever label you give it oftentimes on the ground and in terms of specific policies, it’s the same things that you would do. All right?

So now with a much higher vaccine coverage, although still not perfect, Hong Kong as of today, if you look at, you know, our 70 plus age group with already two doses that’s about 63%, 80 plus is about 47%, all right? And if you look at the one-dose numbers for the 70 plus is 70–73%. So in another month’s time, it will, the two dose will be 70 some odd percent. All right. So much higher than before. Still not perfect, I’d like to see the figure at 90 to 95. All right? So, and when you’ve got 60% of the people who basically have hybrid immunity already, then you need to sort of plot out the next steps.

And you know, I’m the first to acknowledge that I’m a doctor, I’m a scientist, I’m not a politician, I’m not a, an economist, and I’m not a psephologist. People do polling for a, for a living. So I can’t really sort of comment comprehensively on what I call the three-way tug of war in any kind of outbreak control.

First and foremost is health protection. That is the preservation of life. Second force, which can be orthogonal, is economic preservation, looking at GDP, looking at trade, commerce. And then the third force is social wellbeing, including public adherence and acceptability of being willing to go along with measures, right?

So it’s a perennial three-way tug of war. I can only pretend to know a little bit about the health-protection bit. The other two bits, we’ll have to leave to the other domain experts. And I think that for the political classes, it’s their prerogative and responsibility, ultimately, to make a balanced judgment.

Gavin: That’s it for this episode of The Lancet Voice. If you want to carry on the conversation, you can find Jessamy and I on Twitter, on our handles @GavinCleaver and @jessamybagenal. You can subscribe to The Lancet Voice, if you’re not already, wherever you usually get your podcasts. And if you’re a specialist in a particular field, why not check out our In Conversation With… series of podcasts, tied to each of The Lancet’s specialty journals, where we look in depth at one new article per month. Thanks so much for listening and we’ll see you again next time.