RT Journal Article
SR Electronic
T1 Effect of the Tokyo 2020 Summer Olympic Games on COVID-19 incidence in Japan: a synthetic control approach
JF BMJ Open
JO BMJ Open
FD British Medical Journal Publishing Group
SP e061444
DO 10.1136/bmjopen-2022-061444
VO 12
IS 9
A1 Daisuke Yoneoka
A1 Akifumi Eguchi
A1 Kentato Fukumoto
A1 Takayuki Kawashima
A1 Yuta Tanoue
A1 Takahiro Tabuchi
A1 Hiroaki Miyata
A1 Cyrus Ghaznavi
A1 Kenji Shibuya
A1 Shuhei Nomura
YR 2022
UL http://bmjopen.bmj.com/content/12/9/e061444.abstract
AB Background The Tokyo 2020 Summer Olympic Games (23 July–8 August 2021) were held in the middle of Japan’s fifth wave of COVID-19, when the number of cases was on the rise, and coincided with the fourth state of emergency implemented by the host city, Tokyo.Aim This study aimed to assess whether the hosting of the Games was associated with a change in the number of COVID-19 cases in Japan using a synthetic control method.Methods A weighted average of control countries with a variety of predictors was used to estimate the counterfactual trajectory of daily COVID-19 cases per 1 000 000 population in the absence of the Games in Japan. Outcome and predictor data were extracted using official and open sources spanning several countries. The predictors comprise the most recent country-level annual or daily data accessible during the Games, including the stringency of the government’s COVID-19 response, testing capacity and vaccination capacity; human mobility index; electoral democracy index and demographic, socioeconomic, health and weather information. After excluding countries with missing data, 42 countries were ultimately used as control countries.Results The number of observed cases per 1 000 000 population on the last day of the Games was 109.2 (7-day average), which was 115.7% higher than the counterfactual trajectory comprising 51.0 confirmed cases per 1 000 000 population. During the Olympic period (since 23 July), the observed cumulative number of cases was 61.0% higher than the counterfactual trajectory, comprising 143 072 and 89 210 confirmed cases (p=0.023), respectively. The counterfactual trajectory lagged 10 days behind the observed trends.Conclusions Given the increasing likelihood that new emerging infectious diseases will be reported in the future, we believe that the results of this study should serve as a sentinel warning for upcoming mega-events during COVID-19 and future pandemics.Data are available in a public, open access repository. We have uploaded the dataset and associated R programs in the author’s github account (https://github.com/kingqwert/R/tree/master/Synthetic_Olympic).