Reduced mortality in New Zealand during the COVID-19 pandemic

Dec 16

For many countries, the COVID-19 pandemic has unsurprisingly resulted in a marked increase in deaths, compared to those expected based on annual trends. This has not however, been the case for New Zealand. We have published a striking observation in The Lancet; that in 2020 the number of deaths decreased about 4 weeks into the first Alert Level 4 lockdown, falling below that expected based on mortality data from 2011-2019. Interestingly, death rates continued to remain low, even after the Alert Level was reduced and lockdown ended.

In the figure below, you can see the teal line for 2020 mortality diverges from the expected death rate, and remains about 11% lower, from about 4 weeks into the first Alert Level 4 lockdown (pink area):

Weekly all-cause mortality rates are presented per million population for each calendar week. Data from 2011-2019 are shown as mean with 95% confidence interval (calculated using GraphPad Prism 8.3.1). Data for 2020 are provisional and subject to re… — Weekly all-cause mortality rates are presented per million population for each calendar week. Data from 2011-2019 are shown as mean with 95% confidence interval (calculated using GraphPad Prism 8.3.1). Data for 2020 are provisional and subject to revision during the full process of producing death statistics.

The continued reduction in weekly deaths might partly due to the absence of an influenza epidemic in New Zealand in 2020, which is thought to relate to public health measures to prevent COVID-19; (we have published a letter in The Lancet and a comic on this phenomena too).

Influenza cases 2018 to 2020 v05 1600px.jpg

If fewer deaths were related to road traffic accidents, occupational causes, air pollution, and delayed access to healthcare, for example, we would have expected these to rise again following the easing of public health measures like lockdown. Fortunately, this has not been the case. This is a welcome contrast to the experience of many countries facing significantly increased mortality due to direct and indirect effects of COVID-19, and we hope there may be lessons from the Kiwi experience that can help other countries, and our own ongoing planning and response to the virus.

The full letter is available in The Lancet here: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)32647-7/fulltext