Graham Adams: Confessions of an armchair epidemiologist

If Grant Robertson’s handouts to everyone from big business to gig workers have turned us all into socialists within a few weeks, it can equally be said that the relentless barrage of information about Covid-19 from around the world has quickly made us all epidemiologists — mostly of the armchair variety.

I realised I had become part of that rapidly proliferating, raggle-taggle club when I was casually scrolling through the NZ Herald website on Monday morning, and noticed a “Breaking News” banner slide past at the bottom of my phone.

I immediately assumed that a zero had been deleted by mistake. Dr Anthony Fauci — director of the USA’s National Institute of Allergy and Infectious Diseases and an adviser to the White House — had apparently said that Covid-19 might kill as many as 200,000 Americans.

That’s an awful lot of people but I knew the US population of around 330 million is roughly 66 times larger than ours. So Dr Fauci’s estimate of 200,000 deaths would imply a toll here of around 3000 — assuming, of course, that the virus behaves in the same way in different First World countries.

I also knew that just a week earlier, on March 23, Prime Minister Jacinda Ardern had warned the nation that unless “strong action” were taken against the spread of coronavirus “tens of thousands would die”.

When I located the Herald article, I learned Fauci had actually predicted a range of 100,000-200,000 deaths. Reading other reports showed that he was offering what he saw as a realistic middle-of-the-road scenario if Americans ignored stay-at-home directives. If extrapolated to New Zealand, the lower figure would give a death toll of 1500.

Clearly, Dr Fauci’s predictions imply a radically lower toll than the PM’s potential “tens of thousands of deaths” — not to mention the worst-case figure of 80,000 posited by the Auckland University research group Te Punaha Matatini (one of several groups providing modelling of Covid-19 to the government).

Conversely, if Te Punaha Matatini’s modelling were extrapolated to the US, a worst-case scenario would mean a horrifying 5.28 million deaths — yet Dr Fauci thought predictions of 1 million to 2 million deaths there were “almost certainly off the chart”, adding: “Now it’s not impossible, but very, very unlikely.”

As an amateur, of course, I have no idea whether the susceptibility of the US and New Zealand populations to disease is markedly different. I also have no idea whether Dr Fauci or Te Punaha Matatini has the better grip on how Covid-19 might behave if it were left to run its course untrammelled, but it’s also clear that the repeated admonition to listen only to experts will take the armchair analyst only so far — and possibly drive him or her mad in the process of trying to make sense of it all.

When several official models used by the government were released to the media on Tuesday, a University of Otago Wellington research paper — which was given to the Ministry of Health last week — estimated that, if the country failed to stamp out Covid-19, up to 64 per cent of the population could fall ill, with between 8560 and 14,400 people dying. More than 14,000 deaths is a ghastly figure, of course, but it’s a big step down from 80,000.

To an amateur’s eye, it seems that the experts don’t agree on much at all — whether it is the likely death toll for any population, or the best means of halting the virus’ spread, or why Italy has such a shocking tally and Germany doesn’t.

Worse, experts not only have very different opinions but some seem to intensely dislike the opinions that other people in the field have offered.

This became clear on Tuesday, after Stuff published an article by Auckland University epidemiologist Simon Thornley, in which he suggested implementing a widespread lockdown was like squashing a “flea with a sledgehammer” and thereby risking inadvertently taking the entire house down.

He asked whether all the deaths attributed to Covid-19 should have been, and pointed out that in the 2016-17 winter season Italy had many more deaths from a virulent flu than it has had so far from coronavirus.

These comments, among other claims, seemed to make Dr Siouxie Wiles — who teaches at the same university — apoplectic. She took to Twitter to denounce her colleague, albeit without naming him: “For anyone who comes across the opinion piece of an epidemiologist suggesting lockdown is like using a sledgehammer to hit a flea: he studies diet not infectious diseases. Don’t listen to his reckons.”

She later apologised and admitted: “Ok I stand corrected. He is an epidemiologist who studies diet but has also studied the link between scabies & rheumatic fever. RH is an infectious disease. But I still don’t think you should listen to his reckons, as he appears to have done quite a bit of cherry-picked [sic] of data.”

Ironically, Wiles doesn’t appear to be an epidemiologist herself and her research interests are in microbiology — and particularly how bacteria (not viruses) behave — but we armchair enthusiasts don’t care about duelling CVs as much as the quality of the argument.

Along with these battles between experts, we have to grapple with the nagging doubt we are not always being told the whole story by our leaders, who are themselves not epidemiologists. This can be very frustrating for the armchair epidemiologist.

So when the Prime Minister warned us about rumours and misinformation on March 19: “When you see those messages, remember that unless you hear it from us, it is not the truth”, a flaming red flag appears to anyone who has a natural suspicion of authority and who tends not to believe experts just because they are experts.

Consequently, while other more practical friends currently on government-paid furlough were building retaining walls and converting garages to rumpus rooms last weekend, I spent the time trying to work out whether Ardern was telling the truth when she claimed on Friday that, “The number of [coronavirus] tests we are already undertaking for our population size is already very, very good.”

I was suspicious that she might be spinning the facts to suit her political purposes — not least because I had kept a running tally in my mind of the number of tests New Zealand’s Ministry of Health had conducted to date (which I calculated to be a little less than 20,000) and I knew that Australia had done more than 200,000 tests by that time.

Given that Australia’s population is roughly five times ours, I figured, we would have had to have carried out 40,000 tests — not 20,000 — to be comparable.

What amplified my suspicions was the fact the Ministry of Health had stopped announcing the total number of tests and were instead giving an average number of tests over the previous seven days.

Nevertheless, when I asked, the Ministry of Health readily confirmed my rough estimate: “As of 9am today (Sunday March 29), a total of 19,139 tests had been carried out.”

Hmmm… fewer than 20,000 tests in New Zealand compared to more than 40,000 tests (adjusted for population) in Australia appears at first glance to mean Ardern was either misinformed or bending the truth so far it snapped.

However, it seems she may have been correct if she was referring not to the grand total but the number of tests per day, which I calculated were still lagging Australia’s per capita figure but perhaps only by 10 per cent.

When I asked why the total number of tests was not being provided, the Ministry of Health replied that it used “a rolling average because it provides much more accurate information”.

I can’t say I entirely believe that rationale, or why the number of tests made each day shouldn’t be announced along with the total carried out since testing began.

Just four days later, however, we have been told that New Zealand is ramping up its testing from more than 1800 a day on average to perhaps as many as 5000. At least, we have been told that is the health system’s capacity but it remains to be seen how much of that capacity is actually used.

Four days, of course, has become an aeon in the world of politics and of armchair epidemiology as the data swirls and shifts. But as Samuel Johnson observed: “Depend upon it, sir, when a man knows he is to be hanged in a fortnight, it concentrates his mind wonderfully.”

It’s true that for many of us filling in the long hours of our home detention calculating the chances of being hanged by the scourge of coronavirus — physically or financially or both — our minds are, indeed, wonderfully concentrated.

Graham Adams is a journalist, columnist and reviewer who has written for many of the country’s media outlets including Metro, North & South, Noted, The Spinoff and Newsroom

Photo by NIAID on Foter.com / CC BY

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