Victoria may have eliminated COVID-19, but eradication is a distant dream


Michael Toole, Burnet Institute

Today Victoria satisfied a common definition of elimination for COVID-19, recording its 28th consecutive day of zero new cases. While there is no international definition of elimination, two average incubation periods without community transmission is widely accepted as local elimination, especially in a geographically isolated country like Australia.

It’s a remarkable achievement following a severe second wave which peaked at daily new case rates of around 700 in early August. But elimination is not eradication, and we can expect the virus to return at some point, as has happened in several countries that previously boasted minimal or no community transmission.

So how did Victoria get here, and what can it do to keep numbers as low as possible?

Elimination is not eradication

There’s no universal definition of elimination. As applied to other infectious diseases such as polio and measles, it means a prolonged period of zero local transmission in a country or region. For measles, the World Health Organisation (WHO) is very exacting and demands no community transmission for 36 months.

With more than 500,000 new daily COVID cases being reported globally, preventing new local transmission in Victoria will depend on the state building a virus-proof defence.

Several countries have shown the virus can return after a long period of minimal local transmission. The most pertinent example is New Zealand, which experienced 102 consecutive days of zero community transmission before a cluster cropped up in Auckland on August 11. Israel, South Korea, Vietnam and Hong Kong have also experienced reemergence of the virus following significant periods of minimal community transmission. And this month, we witnessed a cluster in suburban Adelaide that originated in a quarantine hotel, after South Australia had experienced many months of no community transmission.




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Indeed elimination doesn’t mean the virus is completely gone. For example, Australia eliminated local transmission of polio in 1972. But it wasn’t until 30 years later, in 2002, that the WHO declared Australia polio-free.

Almost 20 years after that declaration, we still can’t say we’ve eradicated polio because eradication refers to the global removal of a human pathogen; only smallpox has achieved that status. One strain of the polio virus continues to circulate in Afghanistan and Pakistan. In 2007, a 22-year-old student from Pakistan was diagnosed with polio at Box Hill Hospital in Melbourne’s East.

So, how did we get to zero?

Since the grim height of Victoria’s second wave in July and August, several coordinated interventions have eventually borne fruit. One of the most important was the strengthening of the test-trace-isolate-support system. While details are emerging during the parliamentary inquiry into Victoria’s hotel quarantine system, some of the features of this strengthening are known:

  • decentralisation through regional hubs and metropolitan public health units

  • increased engagement and involvement of communities, through programs aimed at public housing estates and local initiatives led by GPs and community health centres

  • adoption of “upstream” contact tracing, identifying contacts of index cases before they developed symptoms as well as after developing symptoms. In both groups, contacts of contacts were identified. This led to the rapid control of clusters such as those in Kilmore and Shepparton.

Other important initiatives included the joint federal-state Victorian Aged Care Response Centre, which eventually managed the explosive outbreaks in residential aged care facilities, and more effective infection prevention and control in health-care settings.

And there were the containment measures that kept people from intermingling. Stage 3 restrictions were reimposed on July 8, limiting the reasons people could leave home. A study published in early August found these restrictions averted between 9,000 and 37,000 cases. From July 23, masks were mandatory at all times outside the home. On August 2, stage 4 restrictions and a night curfew effectively shut down Melbourne. From then on, the number of new cases steadily declined.

Perhaps the greatest achievement of Victoria’s response was to maintain a strong health focus amid a chorus of criticism, much of it from Canberra or the Sydney-based media, pushing the “economy first” mantra. In fact, data show countries that managed to protect the health of their citizens have generally protected their economy more effectively.




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How can we stay where we are?

The first requirement is an effective quarantine system for returned travellers. With cases surging globally, the proportion of travellers who are infected will increase significantly from the 0.7% reported between March and August. This will require arrangements that employ well-trained and adequately paid workers who are regularly monitored by infection control and occupational health and safety experts. The advance contact tracing, which will identify the close contacts of staff before they might test positive for the virus, announced by Premier Daniel Andrews would be a useful adjunct as long as confidentiality is assured.

Crucially, experienced teams of contact tracers must be on standby. They need to maintain the rigorous standards developed over the past few months and engage in simulation exercises that test their capacities. They must retain a focus on community trust and avoid the vilification of individuals that marred the South Australian response.

What’s more, the state must sustain proven containment measures such as physical distancing, hand hygiene, masks indoors, and getting tested if you have symptoms.

Australia is an almost COVID-free oasis, surrounded by a tsunami of virus. Maintaining this status for the next six months or so, while at the same time opening up, will be a huge challenge. Recent responses in Victoria, NSW and SA suggest we are up to it.

And as the story of the sharp-eyed doctor in Adelaide showed us — when she tested a patient in the emergency room who’d initially felt “weak” but had very few COVID symptoms, alerting authorities to the previously silent spread of the virus — to maintain elimination we’re also going to need a little luck.




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The Conversation


Michael Toole, Professor of International Health, Burnet Institute

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.

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



Shutterstock

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.

VIETNAM: AUTHORITIES PRESSURE NEW CHRISTIANS TO RECANT


Converts from ancestral animism threatened with violence, imprisonment.

HO CHI MINH CITY, November 21 (Compass Direct News) – In violation of Vietnam’s new religion policy, authorities in Lao Cai Province in Vietnam’s far north are pressuring new Christians among the Hmong minority to recant their faith and to re-establish ancestral altars, according to area church leaders.

Local authorities have warned that on Sunday (Nov. 23) they will come in force to Ban Gia Commune and Lu Siu Tung village, Bac Ha district, where the Christians reside, but they did not say what they would do.

When the authorities in Bac Ha district in Vietnam’s Northwest Mountainous Region discovered that villagers had converted to Christianity and discarded their altars, they sent “work teams’ to the area to apply pressure. Earlier this month they sent seven high officials – including Ban Gia Deputy Commune Chief Thao Seo Pao, district Police Chief A. Cuong and district Security Chief A. Son – to try to convince the converts that the government considered becoming a Christian a very serious offense.

Christian leaders in the area said threats included being cut off from any government services. When this failed to deter the new Christians, they said, the officials threatened to drive the Christians from their homes and fields, harm them physically and put them in prison.

When the Christians refused to buckle under the threats, a leader of the Christians, Chau Seo Giao, was summoned daily to the commune headquarters for interrogation. He refused to agree to lead his people back to their animistic beliefs and practices.

Giao asked the authorities to put their orders to recant the Christian faith into writing. The officials declined, with one saying, “We have complete authority in this place. We do not have to put our orders into writing.”

They held Giao for a day and night without food and water before releasing him. He is still required to report daily for “work sessions.”

In September, Hmong evangelists of the Vietnam Good News Church had traveled to the remote Ban Gia Commune where it borders Ha Giang province. Within a month, some 20 families numbering 108 people in Lu Siu Tung village had become Christians and had chosen Giao to be their leading elder.

Rapid growth of Christianity among Vietnam’s ethnic minorities in the northwest provinces has long worried authorities. There were no Protestant believers in the region in 1988, and today there are an estimated 300,000 in many hundreds of congregations. As recently as 2003, official government policy, according to top secret documents acquired by Vietnam Christians leaders, was the “eradication” of Christianity.

Under international pressure, however, a new, more enlightened religion policy was promulgated by Vietnam beginning in late 2004. Part of the new approach was an effort to eliminate forced renunciations of faith. The provisions and benefits of such legislation, however, have been very unevenly applied and have not reached many places such as Ban Gia Commune.

Vietnam’s Bureau of Religious Affairs prepared a special instruction manual for officials in the Northwest Mountainous Region on how to deal with the Protestant movement. Published in 2006 and entitled “Concerning the Task of the Protestant Religion in the Northwest Mountainous Region,” this document included plainly worded instructions for authorities to use all means to persuade new believers to return to their traditional beliefs and practices.

This document directly contravened Vietnam’s undertaking to outlaw any forcible change of religion. Under international pressure, the manual was revised and some language softened, but according to an analysis of the 2007 revision of the manual released in February by Christian Solidarity Worldwide (CSW), the language still communicates the goal of containing existing Christianity and leaves the door open to actively stop the spread of Christianity.

The Central Bureau of Religious Affairs instruction manual for training officials shows no change to the 2006 document’s core objective to “solve the Protestant problem” by subduing its development, concluded the February report by CSW and the International Society for Human Rights.

The 2006 manual had outlined a government plan to “resolutely subdue the abnormally rapid and spontaneous development of the Protestant religion in the region.”

“Whereas the 2006 manual provided specific legitimacy for local officials to force renunciations of faith among members of less well-established congregations, the 2007 edition imposes an undefined and arbitrary condition of stability upon the freedom of a congregation to operate,” the CSW report says. “Therefore, the treatment of any congregation deemed not to ‘stably practice religion’ is implicitly left to the arbitration of local officials, who had previously been mandated to force renunciations of faith.”

Without a full and unconditional prohibition on forcing renunciations of faith, the report concludes, the amended manual does not go far enough to redress problems in the 2006 original.

Officials in the remote village of Ban Gia felt no compunction to resort to strong-arm methods to halt the growth of Christianity, said one long-time Vietnam observer.

“When a church leader advised the central government of the problem in Ban Gia Commune, the pressure only increased,” he said. “The unavoidable conclusion is that it is still acceptable in Vietnam for officials to force recantations of Christian faith.”

Report from Compass Direct News