`The statisticians that may have killed New Zealand'

Should statistical modelling drive government strategies? Picture / Supplied

(On Monday) the government made a critical decision regarding whether to extend one of the most draconian Covid-19 mitigation lockdowns of any country in the world.

Last weekend, ministers were studying modelling data from an Auckland University team headed by Professor Shaun Hendy. Professor Hendy recommended we extend the lockdown. He said, 'If it were up to me, I'd be leaning towards taking a little bit longer, make sure those numbers were heading to zero, and that would be the approach I would suggest.'

Hendy's statement shows just how dangerous it is to use statistical modelling experts to drive Covid-19 governmental mitigation strategies.

In the history of all humankind, we have only ever eliminated one major infectious disease, smallpox. Smallpox's eradication was greatly spurred by making use of the fact that transmission occurs via air droplets, just like Covid-19. Initially, to eradicate smallpox, the WHO had pursued a strategy of mass vaccination, which attempted to vaccinate as many people as possible globally, hoping that mass vaccination would create an artificial herd immunity, eventually killing off the virus. People who had been in direct contact with a smallpox patient over the last two weeks were quarantined and vaccinated.

The downside of such an approach was that the virus could spread easily if it were re-introduced from overseas. This was the case in Bangladesh, for example, which had previously eliminated smallpox, until 1972, when it was brought back from across its border with India.

So, lessons learnt are that if we want to eliminate Covid-19 from New Zealand, then we would need to extend our lockdown until no one in the country is infected. In the absence of a vaccine, this may take a lockdown of at least 12-18 months. Then, once we have achieved this, and to maintain our eradication status, we would not allow anyone to enter New Zealand, ever, in case they would bring in Covid-19 from a world outside infected by Covid-19. (We would not have developed any natural herd immunity, and would be susceptible to an imported infection.)

Smallpox was eradicated because all countries worked together with a unilateral strategy to eliminate smallpox.

University of Auckland modelling figures based on overseas data suggested that we would have up to 80,000 deaths due to the Covid-19 virus unless we had a total lockdown.

Australia and countries like Hong Kong have performed far better than New Zealand in terms of the reduction of active cases without a total lockdown and devastation of their economies.

The University of Auckland modelling figures which were based on overseas data were obviously wrong. Using modelling data derived from overseas sources to determine the likely spread of Covid-19 in New Zealand without factoring in local social and demographic data is meaningless.

New York has a population density of 11,000 people per square kilometre, while New Zealand has only 18 people per square kilometre, and Kaitaia has a population density of nine people per square kilometre. The spread of Covid-19 will have a plethora of different variables country to country.

We need to use our own real time data to make qualified informed decisions.

What PM Jacinda Ardern and Shaun Hendy should be modelling is the likely adverse effects of a continued lockdown on our existing appalling health statistics. Our domestic violence statistics are a national shame, and the police and domestic violence groups are seeing a dramatic increase in cases due to the lockdown. We have the highest teen suicide rates in the developed world. Every day one in five of our children goes to school hungry. Every week 16 people in New Zealand commit suicide.

Every year around 500 of our citizens die of flu, but we have never focused on eliminating the disease.

Based on the government's intervention strategies and New Zealand's known Covid-19 case-related mortality rates, this virus will have caused more economic damage, loss of livelihoods, increased suicides, disruption to our education system, inhuman treatment of our elderly and irreversible social changes than actual deaths to date 'associated' with the virus.

We need to focus on facts, not statistical modelling, when it comes to determining the ongoing health and wellbeing of our people.

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Sir Ray Avery is a pharmaceutical scientist and an expert in PPE and the control of microbiological contamination in closed environments such as hospitals and pharmaceutical and medical device manufacturing facilities.