Auckland’s rapid lockdown has given New Zealand a better chance of eliminating coronavirus – again



Fiona Goodall/Getty Images

Michael Plank, University of Canterbury; Alex James, University of Canterbury; Nicholas Steyn, and Shaun Hendy

As Auckland prepares to relax restrictions on Monday, contact-tracing data show the rapid decision to place New Zealand’s largest city under alert level 3 lockdown has undoubtedly prevented an explosive outbreak of COVID-19.

Our model of COVID-19 spread in New Zealand shows the extension by an extra four days at level 3 until Monday has also increased our chances of eliminating community transmission of the virus by about 10%.

Auckland has been at alert level 3 since August 12, less than 24 hours after the first new community cases of COVID-19 in more than 100 days were reported.

Contact-tracing data show that before Auckland’s move to level 3, the reproduction number was between 2 and 3. This means that on average each new case passed the virus on to two or three other people.

If we hadn’t acted quickly, we would have had hundreds of new cases by now, and it would have become far more difficult to bring the outbreak under control.

New Zealand’s largest cluster

The Auckland outbreak is New Zealand’s largest and most complex cluster to date, with 159 people, including 85 who have tested positive and their household contacts.

We have seen transmission in workplaces, churches, public transport and shops, as well as within households.

It has affected Auckland’s Pacific population, who are at higher risk of severe outcomes from the disease. The risks associated with this cluster are higher than those in the first outbreak, reinforcing the need to take a precautionary approach.




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The contact tracing system has been a significant help in containing this outbreak, with more contacts traced faster than earlier in the year. But contacts between strangers are harder to trace, and some could slip through the net.

The fact that the infection was passed between strangers on bus journeys shows how stealthily this virus can spread. It also emphasises how rapidly it can move around the city.

Melbourne attempted to contain its COVID-19 outbreak by locking down certain postcodes, but the virus was always one step ahead and ultimately this tactic didn’t work. The Auckland-wide lockdown has proven to be the right approach.

A worker hands out information to people entering a community testing centre.
Fiona Goodall/Getty Images

Avoiding closed, crowded spaces

Although level 3 restrictions have been effective in preventing exponential growth of the cluster, active cases almost certainly remain in the community. These could easily spark a new outbreak if we relax too soon.

The extra time at level 3 will give us more confidence that the cluster is contained, but it is unlikely we will have completely eliminated the outbreak by Monday.

The Mt Roskill mini-cluster, which now has eight cases, shows we haven’t completely closed this outbreak down yet. But the fact this has now been genomically linked to the main Auckland cluster means it is unlikely to be part of a much bigger outbreak.

How we behave as we go into alert level 2 next week will be crucial in preventing a resurgence. If we can keep the reproduction number below 1, we will eventually eliminate the virus. But if the reproduction number goes above 1, there is a high chance the outbreak will flare up again.

Auckland’s alert level 3 has been successful in preventing rapid growth in the number of cases.
Author supplied, CC BY-SA

Restrictions on gatherings of more than 10 people and compulsory mask use on public transport will help. But the best way to prevent a resurgence of the virus at level 2 is if we all avoid the three Cs: closed spaces, crowded places and close contacts.




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Likelihood of regional spread

So far the cluster has remained largely contained within Auckland. Restrictions on travel in and out of the city have certainly helped to stop the cluster from spreading to other regions.

From Monday, people will be able to travel to and from Auckland freely, and although we have reduced the number of cases in Auckland over the last two weeks, there is a risk of spreading COVID-19 around the country.

The virus could still pop up anywhere and it is essential all New Zealanders stick to level 2 rules, whether they live in Whangārei, Invercargill or anywhere in between.

We don’t necessarily have to get to zero new cases before lifting the level 3 restrictions. As we have seen before, case numbers bounce around from day to day. We may get zero or one cases one day, and four or five the next. What is more important is the type of cases we are seeing.

Last time we were at level 2, from May 14 to June 8, we had a handful of new cases but these were all acquired from a known source. If we get new cases with no apparent link to the cluster, or cases who have been in high-contact situations while potentially infectious, this will be a red flag. It would tell us that there could be many more cases we have missed.

But if most of our new cases are close contacts of existing cases, and ideally already in isolation, this is a good sign that the cluster has been successfully ringfenced.

What next

The criteria for moving to level 1 should be a high probability of elimination. Our previous modelling shows this requires a period of at least ten consecutive days with no new cases, along with widespread testing of anyone with COVID-19-like symptoms.

Once we reach this stage, we should review our level 1 settings. We need to find a way of enabling our economy and society to function while staying ready for the next outbreak. Regular testing of people staying and working in quarantine facilities is one part of this.

But as long as the global pandemic continues to rage, we can’t rely solely on our border — we all need to play our part. Mass masking, precautionary physical distancing and widespread testing at level 1 are low-cost interventions that give us a better chance of detecting an outbreak before it grows too big.

This will minimise the risk of another lockdown next time the virus appears in our community.The Conversation

Michael Plank, Professor in Mathematics, University of Canterbury; Alex James, Associate professor, University of Canterbury; Nicholas Steyn, Research assistant, and Shaun Hendy, Professor of Physics

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How New Zealand could keep eliminating coronavirus at its border for months to come, even as the global pandemic worsens



Mark Baker/AP

Michael Plank, University of Canterbury; Alex James, University of Canterbury; Audrey Lustig, Manaaki Whenua – Landcare Research; Nicholas Steyn; Rachelle Binny, Manaaki Whenua – Landcare Research, and Shaun Hendy

Stringent border controls and mandatory quarantine give New Zealand a good chance to remain free of COVID-19 for months to come, according to our latest modelling.

It’s been 76 days since New Zealand’s last reported case of community transmission, and our model shows the risk of an infectious person slipping through the border undetected remains very low. Provided the rules are followed, we would expect this to happen only once over the next 18 months — and even then, this person may not infect anyone else.

New Zealand’s borders remain closed to everyone except residents, citizens and a small number of foreigners with special exemptions.

Currently about 400 people fly into New Zealand each day. Since June 16, 46 people have tested positive for COVID-19 and of those, 27 remain active cases (at the time of writing). All of them are in quarantine facilities.

Each week, about 12 people have arrived carrying the virus. Provided people are well separated at quarantine facilities and have regular symptom checks, our modelling suggests the risk of an infectious person being released into the community is around 0.1% — which means for every 1000 infected people who arrive at the border, one person will be released from quarantine while still infectious.




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Keeping COVID-19 out

New Zealand has had a total of 1,548 cases of COVID-19 and 22 people have died.

PM Jacinda Ardern.
Daniel Hicks/AP

Prime Minister Jacinda Ardern yesterday announced plans for local or regional lockdowns should the virus reemerge in the community. She referred to the Australian state of Victoria, where the current outbreak appears to be linked to cases at a managed isolation facility, as a cautionary tale for New Zealand.

COVID-19 is exploding outside our borders and every country that we have sought to either replicate or draw experiences from in the fight against COVID-19 has now experienced further community outbreaks. We need only look to the experience of Victoria, Hong Kong, Singapore or Korea to see examples of other places that, like us, had the virus under control at a point in time only to see it emerge again.

Since New Zealand closed its borders on March 19, the rate of COVID-19 infections globally has increased 50-fold, to more than 13 million confirmed cases worldwide.

All new arrivals to New Zealand have to spend 14 days in quarantine at government-managed hotels. Each person has to have a COVID-19 swab test on the third and 12th day of their quarantine period and cannot leave without a negative test result.

A shorter quarantine period would significantly increase the risk of an infectious person being released. The swab tests for COVID-19 have quite high rates of false negative results, so even with multiple tests, a shorter quarantine period could miss too many cases.

Allowing mingling of people within quarantine, or contact between staff and recent arrivals, is also very risky. And our model doesn’t take into account people deliberately absconding from quarantine, which has happened four times. It is incumbent on everyone to do the right thing and follow the rules.




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Managing international travel

How many arrivals could New Zealand cope with? Pre-COVID-19, there were around 20,000 international arrivals on a typical day — 50 times the current number of arrivals. There’s obviously no way we could quarantine this number of people. On current trends, this would mean up to 600 infected people passing through at the border per week.

Reopening borders to return to business as usual is just not an option for the foreseeable future. Any plans to ease border restrictions need to be based on a careful risk assessment. For example, countries such as Taiwan, Vietnam and the Pacific Islands have very low levels of COVID-19. A travel bubble with countries that have eliminated community transmission would present a low risk.

Other groups such as international students or migrant workers who contribute to key parts of our economy should be considered. Anyone coming from countries where COVID-19 is widespread would need to be quarantined on arrival, but quarantine facilities are already stretched to the limit with returning New Zealanders. Implementing any plan to allow other groups into New Zealand safely will take time.

New Zealand is in a rare position of having eliminated community transmission of COVID-19. This means we currently enjoy more freedoms than people in most other countries.

But this elimination status poses its own challenges in returning to life as usual when the rest of the world is in an accelerating pandemic. Other countries that have followed a mitigation strategy are facing equally big social and economic challenges of their own. And this is on top of the devastating health impacts that New Zealand has so far managed to largely avoid.


Oxford COVID-19 Government Response Tracker

Freedom within closed borders

The dilemma New Zealand now faces is whether to continue to enjoy Level 1 freedoms within closed borders or to open borders with more restrictions on what we can do. We could, for instance, allow quarantine-free travel from certain countries. But this might require us to implement Level 2 restrictions (including limits on the size of gatherings) to reduce the risk of superspreading events.




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These are difficult choices, but they are choices and not foregone conclusions. We disagree with the recent claim by former chief science advisor Sir Peter Gluckman, former prime minister Helen Clark and ex-Air New Zealand chief executive Rob Fyfe that new cases of community transmission are “logically inevitable” and New Zealand should therefore reopen borders more quickly.

The recent surge in cases in Melbourne – where 5 million people are now in a six-week lockdown – shows that managing a community outbreak is almost impossible without resorting to strict lockdowns. They have also shown that the most socio-economically disadvantaged people often bear the brunt of lockdown measures, as well as suffering disproportionately from the health impacts of the virus.

These events should serve to remind us just how lucky we are in New Zealand. Let’s not let our guard down now.The Conversation

Michael Plank, Professor in Mathematics, University of Canterbury; Alex James, Associate professor, University of Canterbury; Audrey Lustig, Research scientist, Manaaki Whenua – Landcare Research; Nicholas Steyn, Research assistant; Rachelle Binny, Research scientist, Manaaki Whenua – Landcare Research, and Shaun Hendy, Professor of Physics

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Eradication, elimination, suppression: let’s understand what they mean before debating Australia’s course


Anita Heywood, UNSW and C Raina MacIntyre, UNSW

The current surge in community transmission of COVID-19 in Victoria has brought renewed discussion of whether Australia should maintain its current “suppression” strategy, or pursue an “elimination” strategy instead.

But what do these terms actually mean, and what are the differences between the two?




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In theory

Disease eradication means a global absence of the pathogen (except in laboratories). We achieved this for smallpox in 1980. Diseases suitable for eradication are usually those where humans are the only host, and where there’s an effective vaccine or other prevention strategy.

Disease elimination relates to a country or a region, and is usually defined as the absence of ongoing community (endemic) transmission.

Elimination generally sits in the context of a global eradication goal. The World Health Organisation sets a goal for eradication, and countries play their part by first achieving country-wide elimination.

Cases and small outbreaks may still occur once a disease is eliminated — imported through travel — but these don’t lead to sustained community transmission.

Finally, disease control refers to deliberate efforts to reduce the number of cases to a locally acceptable level, but community transmission may still occur. Australia’s current suppression strategy, though seeking to quash community transmission, can be classified as disease control.

In practice

Elimination and suppression strategies employ the same control measures. For COVID-19, these include:

  • rapid identification and isolation of cases

  • timely and comprehensive contact tracing

  • testing and quarantining of contacts

  • varying degrees of social distancing (lockdown, banning mass gatherings, keeping 1.5m distance from others)

  • border controls: restricting entry through travel bans, and quarantine of returning international travellers

  • face masks to reduce transmission.




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The differences between a suppression strategy and an elimination strategy are the strictness, timing, and duration with which these measures are applied, especially travel restrictions.

For example, under a suppression strategy, physical distancing requirements might be lifted while there’s still a low level of community transmission. But under an elimination strategy, these measures would remain in place until there’s no detectable community transmission.

What’s realistic for COVID-19?

First, the prospect of eradicating COVID-19 is likely no longer feasible, even with a vaccine.

People without symptoms may be able to spread COVID-19, which makes it difficult to identify every infectious case (SARS, for example, was only spread by people with symptoms). And if the virus has an animal host, animal reservoirs would also need to be eradicated.

So what about elimination?

For measles, elimination is defined as the absence of endemic measles transmission for more than 12 months. Countries must demonstrate low incidence, high quality surveillance and high population immunity.

Imported cases in unvaccinated returning travellers and occasional small outbreaks continue to occur, but a country will lose its elimination status if community spread lasts longer than one year.

The majority of the Australian population are immune to measles, which lowers the probability of sustained outbreaks. But most Australians remain susceptible to COVID-19.

So future sustained outbreaks, like the current Victorian outbreak, will remain possible until we can vaccinate the population — even under an elimination strategy.




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Like we have with measles, for COVID-19, we need a definition of elimination with specific criteria that can be measured.

Declaring COVID-19 “eliminated” after the absence of community transmission for a few weeks means little during a pandemic, and may lead to complacency in the community. This period should be more like a few months.

Effective suppression can lead to elimination

While the federal government continues to advocate for its suppression strategy, some states have demonstrated absence of community transmission.

International arrivals to these states (and to New Zealand) are comparatively small, and the virus was always going to be more difficult to contain in cities with substantial international arrivals and high population densities, such as Sydney and Melbourne.

To achieve and sustain national elimination of any infectious disease during a pandemic is ambitious. It requires an epidemiologic definition with measurable criteria, significant resources and almost complete closure of international borders.

But maintaining the right for Australian citizens and residents to return to Australia means the borders are never fully closed, whether under a suppression strategy or elimination strategy.

So ultimately, both strategies are susceptible to outbreaks of COVID-19 in the community as long as the pandemic endures.

It will always ebb and flow

An elimination strategy would not necessarily have prevented the current outbreak in Victoria, particularly if social distancing restrictions had already been lifted.

Whether Australia continues with its suppression strategy or opts to switch to a defined elimination strategy, either approach will require continued vigilance. This could include intermittent reinstating of restrictions or targeted containment around hotspots as transmission ebbs and flows.

And whatever name we give to Australia’s approach, neither Victoria or New South Wales have accepted any level of community transmission. Both have gone hard to stop community outbreaks that have arisen, and that’s a good thing.

But long-term maintenance of periods of elimination are unlikely to be possible until we have a vaccine.




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The Conversation


Anita Heywood, Associate Professor, UNSW and C Raina MacIntyre, Professor of Global Biosecurity, NHMRC Principal Research Fellow, Head, Biosecurity Program, Kirby Institute, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

View from The Hill: Why not have an inquiry to examine the pros and cons of suppression versus elimination?


Michelle Grattan, University of Canberra

Scott Morrison on Wednesday once again ruled out any consideration of moving to an “elimination” strategy for dealing with COVID-19.

He told Triple M Melbourne: “You don’t just shut the whole country down because that is not sustainable.

“There’d be doubling unemployment, potentially, and even worse.

“The cure would be worse than what arguably wouldn’t be delivered anyway, because as we’ve seen with the outbreak in Victoria, it came from a breach of quarantine.

“So unless we’re going to, you know, not allow any freight or any medical supplies into Australia or not allow any exports or anything like this, there is always going to be a connection between Australia and the rest of the world.”

Morrison’s sentiments were backed by the business lobbies. Innes Willox, head of the Australian Industry Group, praised the prime minister for “calling out the prohibitive costs” of an elimination strategy.




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This would mean closing ourselves off from the rest of the world “indefinitely” and require “draconian restrictions” on citizens and businesses, Willox said.

NSW premier Gladys Berejiklian, commenting on the NSW outbreak, also eschewed an elimination strategy.

Even if they are all correct in rejecting elimination, they haven’t properly addressed the arguments, or produced enough evidence to back their assertions.

Instead the government at least – excuse the pun – has sought to suppress the debate about elimination.

Morrison said there would be a “doubling” of unemployment, or worse. Could we have the figures underpinning this please?

At present, in all states and territories apart from Victoria and NSW the virus is effectively or nearly eliminated. So what would happen to unemployment in those states? Maybe a small tick up but you wouldn’t think a lot.

Victoria is once again shut down – triggering more unemployment under the current suppression strategy.

Presumably the treasury could produce some numbers to shed light on the prime minister’s claim.

Morrison’s statement that an elimination strategy would not allow any freight or medical supplies into Australia nor “allow any exports” smacks of exaggeration (at the least). Maximum care would be needed but border issues regarding crews are being managed now.

Willox says elimination would mean closing ourselves off to the rest of the world “indefinitely”.

The first point to be made is that, in terms of the movement of people, we are already closed internationally, apart from those coming home or foreigners leaving. This closure has no end date.

Secondly, after elimination presumably the border could eventually be open to a greater or lesser extent, with a very strict quarantine system.

Morrison’s claim that pursuing elimination would mean shutting down the whole country seems hyperbolic, when we already have extensive elimination. Apart from that, where shutdowns may be needed there can be a trade off – you can have a less severe shutdown but keep some restrictions for longer.

Admittedly, if elimination were successful there would be the danger of complacency, but we’ve seen this under suppression.

Elimination doesn’t mean there will never be cases. It means they are few enough for potential community transmission to be quickly dealt with.

Health experts are divided over whether elimination would be worth pursuing. Victoria’s chief health officer Brett Sutton said on Wednesday: “I’d love elimination. We’re not at a point where it’s the right time to make a detailed consideration of its feasibility, but … it’s worthy of consideration. There’s no question that it’s got its own challenges, but it’s got its benefits as well.”




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Nick Talley, editor-in-chief of the Medical Journal of Australia, a physician and an epidemiologist, believes elimination would be the best strategy for both the society and the economy.

“We eliminated the virus – almost by accident – in large parts of the country during the last lockdown. I suspect this was in part because most of the cases were from international travellers who could be traced and isolated – there was limited community transmission.

“This is very different from the current outbreak in Victoria, and possibly NSW, because there is extensive community transmission,” Talley says.

“I’m not convinced the suppression strategy is going to work. If we don’t eliminate the virus the economy won’t be able to fire up across the country.”

The multiple federal medical officers have backed suppression. Aware of the government’s firm view, they do not freelance.

Both Morrison and Berejiklian have condemned in principle having a stop-start situation. But neither is saying Victoria should have stayed open through its current second wave.

While Morrison and business point to the potential costs of elimination, are they talking short term or long term costs?

For example, New Zealand’s elimination policy is projected to impose a greater economic hit than expected in Australia. But the difference might be somewhat lessened by the second Victorian shutdown, and narrowed further if there are future stop-starts.

It may be that elimination is not the way to go. But why not, say, have a short sharp inquiry, to gather evidence on the health and economic implications, so we know more about the options?

Actually we know why not. The government does not want its course seriously contested.The Conversation

Michelle Grattan, Professorial Fellow, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

We may well be able to eliminate coronavirus, but we’ll probably never eradicate it. Here’s the difference



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Adrian Esterman, University of South Australia

Compared to many other countries around the world, Australia and New Zealand have done an exceptional job controlling COVID-19.

As of May 7, there were 794 active cases of COVID-19 in Australia. Only 62 were in hospital.

The situation in New Zealand is similar, with 136 active cases, only two of whom are in hospital.

If we continue on this path, could we eliminate COVID-19 from Australia and New Zealand?




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Control –> elimination –> eradication

In order to answer this question, we first to need to understand what elimination means in the context of disease, and how it differs from control and eradication.

Disease control is when we see a reduction in disease incidence and prevalence (new cases and current cases) as a result of public health measures. The reduction does not mean to zero cases, but rather to an acceptable level.

Unfortunately, there’s no consensus on what is acceptable. It can differ from disease to disease and from jurisdiction to jurisdiction.

As an example, there were only 81 cases of measles reported in Australia in 2017. Measles is considered under control in Australia.

Conversely, measles is not regarded as controlled in New Zealand, where there was an outbreak in 2019. From January 1, 2019, to February 21, 2020, New Zealand recorded 2,194 measles cases.

For disease elimination, there must be zero new cases of the disease in a defined geographic area. There is no defined time period this needs to be sustained for – it usually depends on the incubation period of the disease (the time between being exposed to the virus and the onset of symptoms).

For example, the South Australian government is looking for 28 days of no new coronavirus cases (twice the incubation period of COVID-19) before they will consider it eliminated.

Even when a disease has been eliminated, we continue intervention measures such as border controls and surveillance testing to ensure it doesn’t come back.

For example, in Australia, we have successfully eliminated rubella (German measles). But we maintain an immunisation schedule and disease surveillance program.




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Finally, disease eradication is when there is zero incidence worldwide of a disease following deliberate efforts to get rid of it. In this scenario, we no longer need intervention measures.

Only two infectious diseases have been declared eradicated by the World Health Organisation – smallpox in 1980 and rinderpest (a disease in cattle caused by the paramyxovirus) in 2011.

Polio is close to eradication with only 539 cases reported worldwide in 2019.

Guinea worm disease is also close with a total of just 19 human cases from January to June 2019 across two African countries.

What stage are we at with COVID-19?

In Australia and New Zealand we currently have COVID-19 under control.

Importantly, in Australia, the effective reproduction number (Reff) is close to zero. Estimates of Reff come from mathematical modelling, which has not been published for New Zealand, but the Reff is likely to be close to zero in New Zealand too.

The Reff is the average number of people each infected person infects. So a Reff of 2 means on average, each person with COVID-19 infects two others.

If the Reff is greater than 1 the epidemic continues; if the Reff is equal to 1 it becomes endemic (that is, it grumbles along on a permanent basis); and if the Reff is lower than 1, the epidemic dies out.

So we could be on the way to elimination.




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In both Australia and New Zealand we have found almost all of the imported cases, quarantined them, and undertaken contact tracing. Based on extensive community testing, there also appear to be very few community-acquired cases.

The next step in both countries will be sentinel surveillance, where random testing is carried out in selected groups. Hopefully in time these results will be able to show us COVID-19 has been eliminated.

The development of a vaccine can help control and eliminate a disease.
Shutterstock

It’s unlikely COVID-19 will ever be eradicated

To be eradicated, a disease needs to be both preventable and treatable. At the moment, we neither have anything to prevent COVID-19 (such as a vaccine) nor any proven treatments (such as antivirals).

Even if a vaccine does become available, SARS-CoV-2 (the virus that causes COVID-19) easily mutates. So we would be in a situation like we are with influenza, where we need annual vaccinations targeting the circulating strains.

The other factor making COVID-19 very difficult if not impossible to eradicate is the fact many infected people have few or no symptoms, and people could still be infectious even with no symptoms. This makes case detection very difficult.

At least with smallpox, it was easy to see whether someone was infected, as their body was covered in pustules (fluid-containing swellings).

So while we may well be on the path to elimination in Australia and New Zealand, eradication is a different ball game.




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The Conversation


Adrian Esterman, Professor of Biostatistics, University of South Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

New roadmap gives Australia two paths out of COVID-19 lockdown: elimination or adaptation


Peter Sivey, RMIT University

Australia is in an enviable position when compared with major world cities like New York, London and Madrid, each of which continues to deal with COVID-19 deaths in the thousands.

Although Australia has suffered 91 deaths, its daily rates of new cases are now in the low double figures or even single figures – evidence of very little community transmission in the country.

This means that unlike places that are still facing lockdown for weeks or months to come, Australia has some crucial imminent policy choices: how to balance the economic and social benefits of easing restrictions with the risks of a future spike in cases.




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Roadmap to recovery

The Group of Eight, an affiliation of leading Australian research universities, this week published a major independent report describing a Roadmap to Recovery for the nation. It sets out some key policy choices, as well as a suite of recommendations to state and federal governments for the months ahead – specifically, beyond May 15, the extent of the federal government’s current restrictions.

The report invites the Australian government to choose between two contrasting but related strategies: “elimination” of COVID-19, and a “controlled adaptation strategy”.

Under the elimination scenario, Australia would continue its nationwide stay-home order (although restrictions currently vary between states) for two further weeks after daily cases reach zero. That means lockdown would last until the end of May or mid-June, given the current trends in cases. But beyond that many social distancing measures could be lifted relatively rapidly, due to minimal risk of community transmission. Travel restrictions would have to remain tight indefinitely, to prevent the possibility of reintroduction of the virus.

In the alternative, “controlled adaptation” strategy, the government would still use aggressive test-and-trace protocols to keep the number of new cases as low as possible. But lockdown restrictions would be lifted earlier – perhaps in the next couple of weeks – although the lifting would necessarily be gradual, with continued social distancing measures applied to shops, schools and workplaces.

Pros and cons

The advantages of elimination is that it prioritises Australians’ health while also affording a more rapid lifting of restrictions once it is deemed safe. For example, restaurants and cafes might perhaps return to serving sit-down customers once elimination has been achieved.

Controlled adaptation will involve more ongoing social distancing. Conceivably, even six months from now, shops and public transport might operate at restricted capacity so people aren’t crowded together. But the advantage of this approach may be in the long term: it prepares Australians for the fact that this virus will probably be circulating around the world for years, and we should adapt our behaviour accordingly.

Furthermore, with improved speed and availability of testing, an adaptation strategy would perhaps allow less stringent international travel restrictions later this year and into 2021. That would be a boon for Australia’s higher education industry, its immigration-dependent construction sector, and its (currently shrinking) overall population.

A ‘continuum’ of choice

Why does the report advocate two strategies, rather than backing just one? The report argues they are not distinct choices, but rather they lie “along a continuum” of strategic options.

So if the government opts to pursue elimination, it would still need to maintain testing and tracing capability in the longer term, as well as continuing to enforce some forms of social distancing even as other restrictions are lifted (for instance, it’s hard to imagine moshing at rock concerts being allowed anytime soon).

Conversely, pursuing a controlled adaptation strategy doesn’t mean Australia can’t also aim to bring cases to zero if possible, as many states are already recording zero cases for several days in a row.

The final exit from either strategy will involve a safe and effective vaccine. Neither allows for the growth of cases contemplated by other countries relying on immunity conferred by people infected with the virus.




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Personally, I favour the end of the continuum that aims at controlled adaptation, rather than aiming for complete elimination of the virus in Australia. Elimination may prove elusive due to the long incubation period and high rate of asymptomatic cases of COVID-19.

But either way, it’s clearly important that cases are kept very low. While the disease disproportionately affects the old, people are still dying early and health economists have shown that an average of between 3 and 11 healthy life-years are still being lost per COVID-19 death.

The rapidly advancing scale and quality of testing and tracing capability should allow for the near-elimination of COVID-19 to continue with mild social distancing measures. Travel restrictions could be eased in the longer term as the pandemic (hopefully) wanes across the world.

Arguably most important of all is for the government to be agile in its approach to the crisis – to keep an eye on the situation both here and abroad, and react accordingly.The Conversation

Peter Sivey, Associate Professor, School of Economics, Finance and Marketing, RMIT University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Why coronavirus emerges in clusters, and how New Zealand plans to eliminate outbreaks after lockdown



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Arindam Basu, University of Canterbury

After four weeks of some of the world’s strictest lockdown conditions, New Zealand now records much higher numbers of people who have recovered from COVID-19 than new infections.

In its April 23 update, the Ministry of Health reported only three new cases – though another two people died, taking the death toll to 16. The total number of cases is 1451, with more than a thousand people having now recovered from the illness.


April 23 update, New Zealand’s Ministry of Health

As New Zealand prepares to ease lockdown conditions from April 28, it can expect new clusters of infections to emerge, as has been happening in northeast parts of China.

But it plans to continue using a combination of testing and contact tracing to stamp out the spread of COVID-19.




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How new clusters can emerge – even with closed borders

New Zealand moves on to two weeks of level 3 lockdown from Tuesday, and people who cannot work from home will start returning to their workplaces, if they can maintain social distancing measures.

Border controls will remain in place indefinitely to avoid new introductions of coronavirus.

Prime Minister Jacinda Ardern has said New Zealand will continue to pursue its goal of elimination with a strategy that differs from most other countries.

Success doesn’t mean zero COVID-19 cases. It means zero tolerance, which means that as soon as we know we have a case, we go in straight away, we’re testing around that person, we’re isolating them […] we do our interviews and contact trace to find all the people who have been in contact with them while they may have passed it on, and we ask them to isolate. That’s how we keep stamping out COVID cases.

New Zealand now has 16 significant clusters, with more than 90 people associated with the two largest of them. People in each cluster are from different households, but they are connected through transmission.

The location of identified COVID-19 cases across New Zealand, shown by district health board area, as of April 23.

As of April 23, 1,065 of New Zealand’s 1,451 COVID-19 cases had recovered, while 16 people had died. This shows total cases by district health board area.

Clusters are the starting points of epidemics or local outbreaks. Epidemiologists think of clusters like networks through which an infection can propagate. If different networks are connected by one or more common members who can travel from one network to another, clusters can join and grow.

Likewise, if networks are kept isolated from each other, the chain of transmission is broken. This is how lockdowns work. Each of our household bubbles is a small network, and as long as we can maintain that bubble without connecting with others outside of our own, we prevent new clusters.

But new cases have continued to emerge because:

  1. even under stringent lockdown conditions and self-isolation, people still need to access public places such as supermarkets where they are at risk of exposure

  2. COVID-19 has a variable infectious period and many people don’t show symptoms but can still infect others

  3. some people within clusters were infected before lockdown started, and continued to infect others within small networks.

Why contact tracing is crucial beyond lockdown

When lockdown conditions ease, people who return to work and children who go back to school will move between networks. This will increase the risk of new infections, but testing has ramped up significantly during the weeks under level 4 conditions and will continue to increase to capture new infections. In some regions, sentinel community testing was carried out to identify any symptom-free cases.

Testing laboratories now process thousands of COVID-10 tests every day, with a record 6480 tests carried out on April 22. The total number of tests is now 101,277.

At the same time, contact tracing has also increased to identify different network structures and clusters. Contact tracers start with an “index” person and track everyone who was connected to that individual to interrupt any forward transmission as the contacts are isolated.




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When the COVID-19 outbreak began in New Zealand, the capacity for contact tracing was limited, but rapid case detection, contact tracing and isolation now has over 90% efficacy against COVID-19 at the population level.

Contact tracing is important for mapping the networks of infected people. “Super spreaders” – individuals who move between clusters – can be identified quickly and their movements tracked. This will help to contain any new clusters.

Manual contact tracing for an outbreak on the scale of COVID-19 needs to be supplemented with digital tools such as Flutracker. The Ministry of Health is also considering a contact tracing app like Singapore’s TraceTogether to prevent large clusters.

With continued contact tracing, we expect the number of new cases to remain low and with border controls preventing imported cases, any emerging new clusters should be able to be detected and contained rapidly. This intervention is central to COVID-19 elimination in New Zealand.The Conversation

Arindam Basu, Associate Professor, Epidemiology and Environmental Health, University of Canterbury

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Eradicating the COVID-19 coronavirus is also the best economic strategy


Brendan Coates, Grattan Institute and Jonathan Nolan, Grattan Institute

Less than a month after restrictions first took effect, Australia appears to have contained the spread of COVID-19 more successfully than we could have possibly imagined.

But we’ve done so at unimaginable cost: large swathes of the economy have been shut down, leaving the livelihoods of millions of Australians on hold indefinitely. With new cases now on the decline, the conversation at today’s National Cabinet meeting will turn to what can reopen, and when.

But the economic costs of re-opening prematurely could be enormous.

The least costly economic strategy is eliminating COVID-19 from Australia altogether. Growing epidemiological evidence suggests it may be possible for us to eliminate coronavirus within the next two to three months.




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New Zealand is pursuing such a strategy.

Australia’s state and territory governments should explicitly declare that they want to eliminate the virus, and maintain harsh lockdown restrictions until new cases are down to zero or close to it.

And in the meantime we’ll accrue invaluable intelligence from other countries about how best to emerge from lockdowns, and plan accordingly.

There’s no doubt this strategy would have big short-term economic costs.

The Organisation for Economic Co-operation and Development estimates that severe shutdowns like our level-three restrictions wipe out almost a quarter of economic activity, costing Australia’s economy about 2% of annual GDP for each month they remain in place.

This means a three-month shutdown would shave six percentage points off Australia’s annual GDP.

But the Government’s unprecedented package of economic support means many firms and households are well-placed to weather a short but severe storm.

Short term pain, long term gain

There’s also enormous economic upside if we eliminate the virus and the economy can more or less return to normal.

Schools and offices could re-open, as could bars, cafes and restaurants. Import and export goods would flow freely. International students could still come to Australia with quarantine and testing, and being COVID-free would mean more would choose Australia over alternative destinations.

Not everything could return to normal. International tourism would take a hit, because tight border controls would be maintained until the pandemic subsides abroad. But international tourism accounts for just 2% of our gross domestic product. And domestic travel would boom.

And while the prospect of 90 days of stage-three restrictions is daunting, it poses fewer economic costs than the alternatives.

Health Minister Greg Hunt has rightly ruled out allowing the virus to spread through the community.




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Even with a so-called herd immunity strategy, there is little chance that economic life would return to normal for at least 12 months. Spatial distancing would still be needed to ensure our hospitals were not overwhelmed, and fear of infection would prevent many people from going outside. Many businesses would remain closed.

Adopting a Goldilocks strategy – where we try to find just the right balance between allowing some economic activity while keeping infections low – would mean fewer die, but would still be bad for the economy.

While there is hope that widespread use of face masks and improvements in tracking and tracing of the disease might change this – there is no certainty.

Sophisticated contract tracing and surveillance were initially effective in helping countries like Singapore to largely stay open, but they too have since resorted to a lockdown to keep infections under control.




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In practice, few sectors currently closed could be reopened in Australia under a Goldilocks strategy.

Modellers at the University of Sydney estimate that even a 20% reduction in spatial distancing compliance would push rates of transmission back above one (that is, where one infected person on average infects more than one other).

That suggests schools could probably re-open, but many workplaces and university classes may have to stay closed.

As would domestic air travel and much non-essential retail. The political lobbying over which industry should have the privilege to re-open first would also be intense.

And whatever is required to keep infection rates stable would need to remain in place until there was herd immunity or a vaccine – and that probably means for as long as 18 months, assuming either happens.

We’ve a choice of a long or a short shutdown

For 18 months of lighter restrictions to be better for the economy than shutting down for another 2-to-3 months to eliminate the virus, the economic costs of a lighter shutdown need to be six to nine times less damaging to the economy than a severe shutdown.

That would require an almost complete removal of spatial distancing, which isn’t on the table.

If there were extended shutdowns, millions of Australians would come out the other side with significant scarring; many would never work again.

Firms that can endure a three-month shutdown without going bust are unlikely to survive for 12 months without further government support. And the budgetary costs of that support would become much bigger for future generations if extended to 12 months or more.




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Relaxing most restrictions without sparking a second round of contagion may be possible in time, but only after making enormous new investments in our ability to identify cases and isolate them quickly.

Economist Paul Romer argues for universal testing of Americans every two weeks; others call for a new digital surveillance state to enforce self-isolation. In each case the technological obstacles are large, and so we should start investing now. Extending the shut down would give us valuable time to prepare if we fail.

It’s commonly assumed that the public health and economic objectives of managing COVID-19 are in conflict. That’s wrong. Eliminating the virus from Australia is the best strategy for our health and for our economy.The Conversation

Brendan Coates, Program Director, Household Finances, Grattan Institute and Jonathan Nolan, Associate, Grattan Institute

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Coronavirus debate turns to whether Australia should embrace ‘elimination’ strategy


Michelle Grattan, University of Canberra

Health Minister Greg Hunt has said the goal of the government’s suppression policy is the “effective eradication” of the coronavirus in Australia – while at the same time casting doubt on the possibility of eliminating it.

Chief Medical Officer Brendan Murphy also was doubtful about being able to eliminate the virus here, saying that would involve very aggressive long term border control.

Both Hunt and Murphy on Monday warned that while an exit strategy from present tough restrictions was on the minds of decision-makers (and the public), now was not the time to take the foot off the brake.

With the number of new cases low (46 over the previous 24 hours on Monday’s figures), shooting for eliminating the virus in Australia is being advocated by some experts as a realistic option.

The national cabinet’s medical advisers are preparing possible scenarios for the period ahead.

Pursuing elimination is the declared policy in New Zealand.

Writing in the Nine media, the Grattan Institute’s John Daley and Stephen Duckett (a former secretary of the federal health department) strongly argue for an elimination strategy.

“The least-bad endgame is to eliminate the virus from Australia, continue to control our borders until there is a vaccine or a cure, and restore domestic economic and social activity to “normal”, albeit keeping a close watch for new cases,“ they write.

“The leading alternative to an elimination strategy is to hold infection rates at close to one – that is, so each infected person on average infects only one other. It’s the “Goldilocks strategy” – it requires us to calibrate social distancing measures with precision. Too tight, and we inflict extra economic damage for a long time. A little too loose, and infections would again grow exponentially.“

Hunt told a Monday news conference that developing herd immunity – deliberately letting the virus spread through a large part of the community in a controlled way – “is not the government’s strategy and it’s not the medical advice.”

He said if it required 60% of the population to get the virus, that would be 15 million Australians. If the death rate were one percent, it would be “an unthinkable strategy and one we reject”.

What the government was doing, Hunt said, was “containment and suppression” with “this goal of effective eradication, but without ever being able to promise that any country could completely do that”.

The current strategy “means that we are giving ourselves the time to plan the exit”.

Murphy said: “The challenge with elimination is that nobody yet knows whether it’s possible. We don’t know to what extent there is asymptomatic transmission of this virus.

“The challenge … also with an elimination strategy is that you have to keep the most aggressive border measures in place for a very long time – potentially until you’ve got a vaccine.”

Murphy said one reason for New Zealand’s keenness to be very aggressive was its shortage of critical care beds. It had fewer of these beds as a proportion of population than Australia had.

While cautioning in general about early lifting of restrictions, Murphy said one thing the national cabinet was “quite keen to do is to get children back to school,” although he conceded some states were keener than others.

Scott Morrison has been consistently wanting to ensure schools are functioning so parents can work. It was the premiers, led by NSW and Victoria but in other states too, who wanted people to keep children home, which has become the general model, except for parents unable to do so.

Education Minister Dan Tehan last week warned independent schools they face their funding being cut if they don’t stay open for those who need them.

Murphy said: “we are working with some advice for the national cabinet on how schools can be made a safer environment to prevent transmission, if it does occur between children, and to protect teachers. So that’s one very important measure that the national cabinet is keen to get advice on.”The Conversation

Michelle Grattan, Professorial Fellow, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

NRL Finals Series: Manly and New Zealand Gone – 6 Teams Remain


The first weekend of the NRL final series has seen both the Manly Sea Eagles and the New Zealand Warriors eliminated from the competition. Remaining in the competition are St. George Dragons, Gold Coast Titans, Sydney Roosters, Canberra Raiders, Penrith Panthers and the West Tigers.

In week 2 of the final series St. George and the Gold Coast Titans get the weekend off.

Next weeks elimination matches will be between the Sydney Roosters and Penrith Panthers, and the Canberra Raiders and the West Tigers.