Conflicting COVID-19 excess mortality estimates

To estimate the COVID-19 death toll, the COVID-19 Excess Mortality Collaborators¹ have presented excess mortality estimates for 2020–21 for all countries in the world. We argue that for many countries, these estimates are implausible because they imply an unrealistic number of expected deaths, inconsistent with trends before the pandemic. A case in point is Japan, where the authors estimated 111 000 (95% CI 103 000–116 000) excess deaths from Jan 1, 2020, to Dec 31, 2021—an order of magnitude higher than the estimate by The Economist ² (12 000) and qualitatively different from the World Mortality Dataset's³ negative estimate (–13 100). The COVID-19 Excess Mortality Collaborators define excess mortality as “the difference between reported all-cause mortality […] and what would have otherwise been observed without the COVID-19 pandemic”. For Japan, 2 836 833 deaths were observed in 2020–21. The estimate of 111 000 excess deaths thus implies 2 725 833 expected deaths. The expected deaths are 0·9% lower than the number of observed deaths in 2018–19 (2 750 245), suggesting that in the absence of the COVID-19 pandemic there would have been a drop in death counts.

However, declining deaths are not in line with the historical trend: the number of annual deaths has been growing without interruption in the past 20 years, with biannual changes in death counts from 2000 to 2019 all being between +1·5% and +7·3% (appendix 1 p 1). By contrast, expected death estimates by the World Mortality Dataset and The Economist do not break with the past trend. We found similarly implausible excess mortality estimates for many other countries, including Denmark, Germany, Belgium, Spain, Portugal, and Kazakhstan (appendix 1 p 1; appendix 2 p 2 for calculations). We believe that the estimates of the COVID-19 Excess Mortality Collaborators are unreliable and should not be used for any policy evaluation.

We declare no competing interests.