Modelling doomsday or reality?

It made a strange kind of sense that, when Auckland University physics professor Shaun Hendy delivered Te Pu¯naha Matatini’s latest modelling on Covid-19 and vaccinations at Parliament on Thursday, he beamed in on a big-screen TV like a science-fiction villain addressing Earthlings from space.

It made sense because Hendy’s numbers were so alarming as to be almost apocalyptic. A radio host even dubbed it ‘‘the doomsday model’’. The headline figure was that, even if 80 per cent of New

Zealanders aged 5 and over are fully vaccinated, Covid-19 would still deliver a terrifying death toll. The modelling suggested the virus would kill nearly 7000 people in a year and hospitalise almost 60,000 of us, without other containment measures.

Of course, these numbers fall as vaccination rates go up, thus reinforcing the Government’s message to get vaccinated. Hopefully the fence-sitters, procrastinators and anti-vaxxers will reconsider.

Some have argued that fear is no incentive and that, like a parent, the Government should aim to encourage good behaviour rather than scaring people out of bad behaviour. Some say fear does not work as a motivator, but the impressive uptake in vaccinations during the recent lockdown would suggest otherwise.

But were these numbers realistic or exaggerated? Alex James, associate professor at the School of Mathematics and Statistics at the University of Canterbury, described the model as ‘‘the absolute worst-case scenario’’. Others have backed it, including Auckland University epidemiologist and data scientist Janine Paynter.

The most outspoken critic is Rodney Jones, an economist who, like Hendy, has advised the Government on its Covid response. Without presenting an alternative model, Jones called the Te Pu¯naha Matatini numbers implausible, and compared the projected rate of 140 deaths per week with Singapore, which has had 11 deaths per week with just under 80 per cent vaccinated, in a population of a similar size. Others, including Paynter, argue that New Zealand and Singapore are not directly comparable.

Another point is that, while 80 per cent sounds like a lot, if you turn the numbers around, it means there would be roughly 1 million unvaccinated New Zealanders. Suddenly, 7000 deaths looks a little more plausible.

But has the Government gone lukewarm on the alarming numbers?

Some will have seen Deputy Prime Minister Grant Robertson’s comments yesterday, when he said that ‘‘there are different modellers with different views about these matters’’ and that he was ‘‘not going to wade into the debate’’, as a less than wholehearted endorsement of an expert the Government had platformed only a day earlier.

Whether you are Hendy or Jones, the bottom line is the same. We need to keep vaccinating as fast as we can, and we especially need to find ways to get to the harder-toreach communities whose numbers continue to lag behind.