Long-term mortality study highlights effectiveness of New Zealand COVID-19 public health measures

There has been much speculation about the possible long-term effects of Aotearoa New Zealand’s COVID-19 elimination strategy on mortality rates and, in particular, whether it might have led to a rebound increase in loss of life from other causes.
 
This speculation has been put under a scientific lens by the Medical Research Institute of New Zealand (MRINZ), through an analysis of weekly all-cause New Zealand mortality rates using data from Stats NZ Tatauranga Aotearoa.

A study, published by the MRINZ in the prestigious international medical journal The Lancet shows that while there has been a significant burden of COVID-19 deaths there has not been a substantive rebound in deaths from non-COVID causes since December 2021, when New Zealand moved from an elimination strategy to a mitigation strategy after achieving high vaccination rates.

“The patterns of mortality observed in the study are informative in terms of guiding public health measures for future pandemics.” says Dr Thomas Hills, study author, and COVID-19 programme lead at the MRINZ.

The report showed that in 2020, the elimination strategy not only successfully eradicated COVID-19, but also resulted in an 11% reduction in all-cause mortality over a 30-week period, an outcome that contrasted markedly with most other countries globally in which all-cause mortality increased due to the pandemic.

In fact, there were around 440 fewer deaths per million in New Zealand in 2020, likely due to numerous potential factors including the elimination of COVID-19, markedly reduced burden of influenza and other respiratory viruses, and fewer deaths from road traffic accidents, occupational causes, air pollution and post-surgical complications. In 2021, weekly mortality rates fluctuated around the historical average. In 2022 when widespread community transmission of the Omicron variant occurred, the New Zealand population was highly vaccinated, and public health restrictions were progressively relaxed. During this time there was excess mortality of about 660 deaths per million population, predominantly due to COVID-19.

As a result, total mortality rate minus COVID-19-attributable deaths was 444·5 fewer deaths per million population in 2020, 11·7 fewer deaths per million population in 2021, and 209·3 more deaths per million population in 2023 compared with historical rates.

“New Zealand has been a country of considerable global interest in view of its elimination strategy for COVID-19, which prevented the high rates of mortality from COVID-19 experienced by most other countries.” says Professor Richard Beasley, study author and MRINZ director. “What this study has shown is that the benefits have been maintained long term, even after relaxation of most of the public health measures.”

Full study article here ➡️ https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)01368-5/fulltext. ‘New Zealand’s COVID-19 elimination strategy and mortality patterns’ study, is authored by Stacey Kung, Thomas Hills, Nethmi Kearns, and Richard Beasley, and published in the Lancet on Thursday 24 August, UK time.