Wednesday, October 15, 2025

Counting the true toll of the COVID-19 pandemic in New Zealand – IJEblog


Michael Plank

How many individuals died due to the COVID-19 pandemic in New Zealand? It feels like a easy query, however the reply is dependent upon extra than simply counting reported COVID-19 deaths.

In our current examine, revealed within the Worldwide Journal of Epidemiology, we checked out a key statistic referred to as extra mortality – the variety of deaths above what we might have anticipated if there hadn’t been a pandemic. Extra mortality helps us to measure the general influence of the pandemic, not simply from COVID-19 itself but in addition from issues like delayed medical care or the unintended effects of lockdowns.

Many individuals will likely be aware of the Our World in Information COVID-19 dashboard, which permits customers to check extra mortality between nations. This dashboard exhibits that New Zealand’s complete extra mortality as much as the top of 2023 was lower than 1%. In different phrases, the variety of deaths throughout the pandemic was lower than 1% increased than anticipated.

However not everybody agrees with this conclusion.

A examine by John Gibson argued that the surplus mortality in New Zealand was really a lot increased than this. Our World in Information’s methodology missed a vital issue: New Zealand’s inhabitants progress floor to a halt in 2020 because of pandemic journey restrictions. With fewer folks within the nation, Gibson claimed, we must always have anticipated fewer deaths; so the surplus mortality was really increased.

We wished to know if this was actually true. Might the Our World in Information dashboard be inadvertently hiding a swathe of extra deaths in New Zealand?

To reply this query, we constructed a statistical mannequin that estimated traits within the loss of life fee over time. We then used this mannequin to calculate what number of deaths would have been anticipated if the pandemic had by no means occurred and pre-pandemic traits had merely continued.

Our mannequin accounts for modifications in inhabitants dimension and age to make sure a good comparability. We checked out extra mortality as much as the top of 2023 as a result of we wished to incorporate the interval after New Zealand’s elimination technique ended and the virus grew to become widespread.

Was New Zealand’s pandemic loss of life toll increased than reported?

The reply from our work is a convincing “no”.

We discovered that the full variety of deaths between 2020 and 2023 was someplace between 2% increased than anticipated and 0.8% decrease. In different phrases, we are able to’t be assured that extra folks died throughout the pandemic than would have died anyway. We can be assured that the variety of deaths was not more than 2% increased than anticipated.

In 2020, the variety of deaths was unusually low, primarily as a result of border closures and lockdowns inadvertently worn out influenza in addition to COVID-19. In 2022 and 2023, deaths elevated as COVID-19 grew to become widespread. The sample of extra deaths matched very intently with reported COVID-19 deaths, suggesting that the virus itself, moderately than oblique elements, was the primary driver.

Total, New Zealand’s estimated extra mortality of lower than 2% is way decrease than that in nations like the UK (10%) or United States (11%) over the identical interval.

So why the controversy?

Gibson was proper that New Zealand’s inhabitants progress stalled throughout the pandemic. However that’s solely a part of the story.

Most deaths occur in older folks, and this phase of the inhabitants continued to develop in dimension throughout the pandemic. So, regardless that complete inhabitants progress slowed, the variety of aged folks – the group at highest danger of dying – nonetheless elevated as anticipated.

In different phrases, New Zealand’s ageing inhabitants was a extra vital driver of the anticipated variety of deaths than the variety of immigrants, who are typically comparatively younger.

Why does this matter?

The following pandemic is a query of when, not if. If we’re to reply higher to future pandemics, it’s important that we perceive the complete influence of our response to COVID-19.

Some critics argue that New Zealand’s elimination technique simply delayed the inevitable. Deaths that had been prevented in 2020 and 2021 – the argument goes – had been merely delayed till 2022 or 2023, when the virus grew to become widespread.

However the knowledge inform a special story. Our response purchased time for folks to get vaccinated earlier than they had been uncovered to the virus. And that massively lowered the fatality danger.

New Zealand’s response was removed from good, and there have been undoubtedly harms because of lockdowns and different measures that aren’t mirrored in mortality statistics. However there may be little question that the response saved hundreds of lives in contrast with the alternate options.


Learn extra:

Plank MJ, Senanayake P, Lyon R. Estimating extra mortality throughout the Covid-19 pandemic in Aotearoa New Zealand. Int J Epidemiol 2025; 54: dyaf093.

Michael Plank (@michaelplanknz.bsky.social) is a Professor within the College of Arithmetic and Statistics on the College of Canterbury, a Fellow of the Royal Society Te Apārangi, and an Investigator at Te Pūnaha Matatini, New Zealand’s Centre of Analysis Excellence in Complicated Methods and Information Analytics. His analysis makes use of mathematical and statistical instruments to assist perceive and reply to advanced organic and epidemiological methods. He was a member of the crew that gained the 2020 New Zealand Prime Minister’s Science Prize and was awarded the 2021 E. O. Tuck Medal for excellent analysis and distinguished service to the sector of Utilized Arithmetic.

Battle of curiosity: Michael Plank led a bunch of researchers who had been commissioned by the New Zealand Authorities to supply modelling in assist of the response to COVID-19 between 2020 and 2023.

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