key: cord-0859464-pw6874tu
authors: Yorifuji, Takashi; Matsumoto, Naomi; Takao, Soshi
title: Excess All-Cause Mortality During the COVID-19 Outbreak in Japan
date: 2021-01-05
journal: J Epidemiol
DOI: 10.2188/jea.je20200492
sha: dcd0bf81194b9adf6864aba6ab4f19948b2b8c92
doc_id: 859464
cord_uid: pw6874tu

nan

was identified in January, and the number of patients peaked in mid-April and in July ( Figure 1 ). The excess mortality (number) was positive only in April (about 2,000 excess deaths), but was negative for the other months during the study period. Prefectures with a higher COVID-19 incidence tended to have an increased excess mortality rate (r = 0.43); however, there was a negative excess mortality rate in all except two prefectures ( Figure 2 ).

These results demonstrate that excess mortality in Japan occurred only in April 2020 (at the first peak of the COVID-19 outbreak). In contrast, the numbers were negative in the other assessed months. Overall, therefore, net mortality decreased during the study period compared with the previous 2 years (2018 and 2019). Moreover, although there was a positive prefecturelevel relationship between cumulative COVID-19 incidence and excess mortality rate, most prefectures had a negative excess mortality rate. We obtained the cause-specific cumulative number of mortalities from January to May in Japan (2018-2020), when the latest cause-specific mortality data were available, from the Monthly Vital Statistics Report from the Ministry of Health, Labour and Welfare in Japan. We then show the percent change relative to the number of deaths in 2018 in each year separated by selected causes of death ( Figure 3 ). This figure shows that the decreased monthly and net mortality are partly explained by decreased mortality related to infection, including influenza 6 or pneumonia, owing to the reduced transmission risk, accidents possibly due to the lower social activity, 7 or circulatory diseases. Although a limitation of our study is that we did not consider excess mortality during the second wave of COVID-19 infections in July=August 2020, the results suggest that public health regulations aimed at preventing COVID-19 may incidentally reduce mortality related to influenza and other infections or other causes and consequently contribute to reduced net mortality. 

World Health Organization. Coronavirus disease (COVID-19) pandemic. https:==www.who

Excess all-cause mortality during the first wave of the COVID-19 epidemic in France

DOHMH) COVID-19 Response Team. Preliminary estimate of excess mortality during the COVID-19 outbreak

Excess all-cause mortality during the COVID-19 pandemic in Europe -preliminary pooled estimates from the EuroMOMO network

Ministry of Health Labour and Welfare in Japan. About Coronavirus Disease 2019 (COVID-19). https:==www.mhlw.go.jp=stf= seisakunitsuite=bunya=newpage_00032.html Accessed

Seasonal influenza activity during the SARS-CoV-2 outbreak in Japan

http:==www.npa.go.jp=publications=statistics=koutsuu=index_jiko.html Accessed

We appreciate Saori Irie for her valuable support in collecting the data. We thank Kelly Zammit, BVSc, from Edanz Group (https:== en-author-services.edanzgroup.com=ac) for editing a draft of this manuscript.Authors' contributions: TY analyzed the data and wrote the first draft, NM and ST contributed to the interpretation of the data and revised the manuscript. All authors read and approved the final draft.

Source of funding: The present study was supported by grant no. 7402000035 from Okayama Prefecture for the COVID-19 outbreak investigation.Conflicts of interest: None declared.