Ian Powell: Eliminate or Mitigate; why not Exterminate?

Ian Powell: Eliminate or Mitigate; why not Exterminate?

Should the approach towards Covid-19 be to eliminate (such as China and New Zealand) or mitigate (Sweden) this dangerous virus?  This is the question that countries must consider. Professors Michael Baker and Nick Wilson (both public health specialists) describe the differences between elimination and mitigation in their 10 April Guardian article Elimination: what New Zealand’s coronavirus response can teach the world.

As the epicentre of the virus quickly migrates to the United States, some supporters of Trump’s approach describe it as “mitigation”. This is generous, as mitigation requires thought processes. Instead, the US is in serious trouble. Despite being the richest country in the world, it doesn’t have a universal public health system. This means that it has no coordinated and integrated means of responding to pandemics. Being led by an incompetent narcissist adds to the country’s crisis.

In New Zealand, epidemiologist Dr Simon Thornley has advocated mitigation in his Stuff opinion piece on 31 March and his Newstalk interview with the opinionated right-winger Mike Hosking the following day.

Dr Thornley questions whether the consequences of the Government’s lockdown match the threat, implying that they don’t, and asserts, without explanation, that Sweden provides a “more sensible course”.  To support this view, he makes a reasonable observation about the overestimated number of deaths from the threat of swine flu in 2009. But, aside from the fact that viruses and flus are not the same, there are two factors which provide fuller context.

First, the World Health Organisation was criticised for overstating the threat of swine flu. This included the required level of vaccine doses made by international pharmaceutical companies – who stood to gain by the threat – unduly influencing WHO’s estimates. While WHO has defended its position, it did acknowledge shortcomings, including communication. Nevertheless, patients did die and at certain points these patients took up to 20% of intensive care unit (ICU) beds and 25% of ICU activity.

Second, learning from the SARS experience in 2003, a good pandemic plan with significant public health specialist involvement, was developed. It led to public health measures that helped reduce the swine flu threat.

Dr Thornley is not alone (not quite at least). His argument for mitigation is supported by his clinical leader Professor Grant Schofield in his 8 April Newsroom article. Professor Schofield levered off Director-General of Health Dr Ashley Bloomfield’s (also a public health specialist) response to a media conference question that there is “no Plan B” if the shutdown doesn’t work. The consummate Dr Bloomfield slightly dropped the ball by saying there wasn’t. Many years ago, in media training I was advised that if I didn’t like a question from a journalist, then answer the question you think they should have asked.

Professor Schofield’s article over a week after his colleague’s is surprising as, aside from endorsing Dr Thornley’s data arguments, his points are largely at the level of generality. Dr Thornley’s arguments on data were indirectly rebutted by professors Baker and Wilson in their subsequent Stuff feature.  When Dr Thornley wrote his article, it was unclear whether New Zealand’s elimination approach would work. At the time of Professor Schofield’s publication, there was encouraging news about elimination especially in China but also New Zealand. While a week is a long time in politics, a day is an eon in viruses.


Dr Thornley suggests that patients who are already sick, especially the elderly and those with comorbidities, should not be included in the Covid-19 data. He refers to Italy’s high infection rates to highlight his point. Italy does have a higher proportion of older people compared with most countries.  But many of the cases are from Lombardy in the north where air pollution is high and so making people more vulnerable to Covid-19.

Dr Thornley’s discussion of comorbidities made me uncomfortable. Comorbidities are often not terminal illnesses or confined to older people. The reader is left with the suggestion that they are and that many of them are about to die soon. But many of them can expect to live for several years.  Comorbidities are when there are one or more diagnosable medical conditions alongside a primary condition. Examples include depression, diabetes, hypertension, obesity, schizophrenia, various chronic illnesses, and anxiety. Some of these, such as diabetes, can be either a primary condition or comorbidity depending on the individual patient’s circumstances. With good management diabetes patients can live long lives.

A form of mitigation is “herd immunity” which involves taking no or few measures to combat Covid-19 for most of a country’s population.  The theory is that when about 60% of the population is infected then immunity will be achieved. With so much infection spreading, many older people and others with comorbidities would die.

Herd immunity has been attempted in three European countries – the United Kingdom, Netherlands and Sweden. The United Kingdom explicitly promoted herd immunity until the opposition of concerned doctors, scientists and researchers led to a U-turn.  But the attempt contributed to infection and death rates soaring. Boris Johnson’s near-death was due to this stupidity. He needs a stern reprimand in the same way as an immature teenager who drinks a bottle of bleach for fun would.  The Netherlands also dropped this response for similar reasons.

The Swedish experience

Sweden is recommended by Dr Thornley.  Its government rejects the herd immunity label.  Instead it describes its response to Covid-19 as mitigation through personal responsibility (a libertarian argument).  But if something looks like a herd and makes noises like a herd then “herd immunity” it is.

Sweden was hit by a rapid rise in infections in mid-March and subsequently in death rates.  It has twice the population of New Zealand. Our current death rate is four. Putting everything else aside Sweden’s should be around 8-10. But, according to the World Health Organisation (WHO), as of 10 April Sweden had 793 deaths (106 that day alone). At the time of Dr Thornley’s article (31 March) Sweden’s death rate was 146 with a 33% increase (36) on that last day. Over the following 10 days its total number of Covid-19 deaths increased by a massive 647 (443%).

Considering Sweden’s high death rate, it is inexplicable that it should be promoted as an example for New Zealand to follow.  Herd immunity is high risk and indicates a low assessment of the value of human life.  It is a highly unethical and dangerous experiment in the absence of an available specific vaccine.


Dr Thornley correctly stated in his article that infection rates can be skewed where sick people are tested first, as is the case in New Zealand. In his subsequent Mike Hosking interview, he made a brief reference to Iceland and its proactive testing. He is right to commend Iceland which has now tested 10% of its population, more than any other country.  The trick was that Iceland got in quick with testing beginning in early February. Two different organisations were involved. Their national university tested the referred unwell while a separate organisation randomly screened other Icelanders. This enabled them to better understand the geographic origins of the virus including any mutations. Testing was quickly followed by contract tracing and social isolation. Its work, particularly randomised screening, also reveal the alarming result that around half of those infected were asymptomatic.

Iceland has not had the strict shutdown that New Zealand has. It allowed for gatherings of up to 20 people. Testing was extensive early, thereby obtaining valuable information. It was very prompt with strict border closures. Social distancing was strict. Iceland is a small country with a small population; around 360,000 of which nearly 130,000 (over a third) live in the capital, Reykjavik. I had the pleasure of spending over a week in the country in late 2018 for meetings of the World Medical Association. It is a unique place with a fascinating evolving geology that is an orgasmic experience for geologists. And it is exceptionally cold. Many locals stay indoors as much as possible. Climate is a form of compulsory self-isolation.

But, while Iceland offers lessons for New Zealand, particularly in respect of testing, the former’s death rate is higher.  At six, it is two more than New Zealand’s, but our population is nearly 14 times more.


Understandable alarm has been expressed over the serious risks to the economy as a result of the shutdown.  But, aside from the value of human life, we should consider the economic consequences of not shutting down the country for a period.  According to modelling from the University of Otago public health specialists, we would have around 14,000 deaths, up to 64% of the population infected, and around 32,000 people hospitalised.

Further, many patients requiring treatment for other acute illnesses would die because our hospitals would be clogged up, many patients requiring less urgent treatment would see their health deteriorating, and many other patients referred by their GPs for a specialist assessment of their condition and necessary treatment would be stranded. Would the economic impact of such a protracted sick workforce be worse than the shutdown?

New Zealand’s decision to go down the elimination path was made in mid-March but earlier decisions, including border closures and requiring social distancing, helped enable this. There are legitimate criticisms that can be made. Our hospital workforce capacity is vulnerable; there is concern over the effectiveness of aspects of the border controls; concerns from health workers over the timely provision of sufficient safety equipment and resources remain. Our testing and contact tracing should have started earlier and been more extensive. Workforce capacity limitations and availability of consumables have been behind this.

We would have been in serious trouble if the Government’s strategy hadn’t worked, because hospital specialist shortages and burnout due to longstanding neglect would have meant that they couldn’t cope with the tsunami of admissions that other countries have experienced.

But it is working so far. We have to date avoided the massive exponential increases, including death rates and hospital admissions, that many other countries have experienced to their cost.  In fact, the trends appear now to be going in the opposite direction. It is still too early to be confident as the results to date have been either pre-shutdown cases (or in its first few days). A remaining unknown is the full extent of community transmission. But we compare well with Australia. If that country was performing as well as New Zealand, their deaths should be around 20-25. It is over 50.

There are three things that ultimately will deal to this virus.  The first and most important is effective social distancing, including shutdowns. The second is a vaccine, but this is a very long time away. The third, where interesting possibilities are emerging, is anti-viral drugs which inhibit the development of viruses in those infected.

It would be irresponsible to shift from elimination to mitigation now when we (and China) are now seeing some light at the end of the tunnel. If I had my way I would go further and call elimination “extermination”.  I would recruit the Daleks from the early Doctor Who television series. Daleks were robotic creatures rolling around saying “exterminate, exterminate, exterminate”. But, on this occasion, they would be unbeatable, because Doctor Who would be on their side.


Ian Powell was formerly the Executive Director of the Association of Salaried Medical Specialists for over 30 years until December last year.  He is now a health commentator based in Otaihanga on the Kapiti Coast.