TY - JOUR
T1 - COVID-19 risk assessment at the opening ceremony of the Tokyo 2020 Olympic Games
AU - Murakami, Michio
AU - Miura, Fuminari
AU - Kitajima, Masaaki
AU - Fujii, Kenkichi
AU - Yasutaka, Tetsuo
AU - Iwasaki, Yuichi
AU - Ono, Kyoko
AU - Shimazu, Yuzo
AU - Sorano, Sumire
AU - Okuda, Tomoaki
AU - Ozaki, Akihiko
AU - Katayama, Kotoe
AU - Nishikawa, Yoshitaka
AU - Kobashi, Yurie
AU - Sawano, Toyoaki
AU - Abe, Toshiki
AU - Saito, Masaya M.
AU - Tsubokura, Masaharu
AU - Naito, Wataru
AU - Imoto, Seiya
N1 - Funding Information:
A.O. receives a personal fee from MNES Inc., unrelated to the submitted work. Other authors declare no competing interests. This research project comprises other members from two private companies, Kao Corporation and NVIDIA Corporation, Japan. K.F. is affiliated with Kao Corporation, but no other authors receive any financial support from the Kao Corporation or NVIDIA. Y.I. and W.N. received financial support from the Kao Corporation for their 3-year collaborative research project until March 2020 in context outside the submitted work. T.Y., T.O., and W.N. will receive financial support from the Kao Corporation for their collaborative project from April 2021. No external financial support is used for this article. The findings and conclusions of this article are solely the responsibility of the authors and do not represent the official views of any institution.
Funding Information:
We thank Editage and Business Quest Limited Company for language editing. We thank Mr. Tsukasa Fujita for his support.
Publisher Copyright:
© 2021 The Author(s)
PY - 2021/12
Y1 - 2021/12
N2 - The 2020 Olympic/Paralympic Games have been postponed to 2021, due to the COVID-19 pandemic. We developed a model that integrated source–environment–receptor pathways to evaluate how preventive efforts can reduce the infection risk among spectators at the opening ceremony of Tokyo Olympic Games. We simulated viral loads of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emitted from infectors through talking/coughing/sneezing and modeled temporal environmental behaviors, including virus inactivation and transfer. We performed Monte Carlo simulations to estimate the expected number of newly infected individuals with and without preventive measures, yielding the crude probability of a spectator being an infector among the 60,000 people expected to attend the opening ceremony. Two indicators, i.e., the expected number of newly infected individuals and the newly infected individuals per infector entry, were proposed to demonstrate the extent of achievable infection risk reduction levels by implementing possible preventive measures. A no-prevention scenario produced 1.5–1.7 newly infected individuals per infector entry, whereas a combination of cooperative preventive measures by organizers and the spectators achieved a 99% risk reduction, corresponding to 0.009–0.012 newly infected individuals per infector entry. The expected number of newly infected individuals was calculated as 0.005 for the combination of cooperative preventive scenarios with the crude probability of a spectator being an infector of 1 × 10−5. Based on our estimates, a combination of cooperative preventions between organizers and spectators is required to prevent a viral spread at the Tokyo Olympic/Paralympic Games. Further, under the assumption that society accepts < 10 newly infected persons traced to events held during the entire Olympic/Paralympic Games, we propose a crude probability of infectors of < 5 × 10−5 as a benchmark for the suppression of the infection. This is the first study to develop a model that can assess the infection risk among spectators due to exposure pathways at a mass gathering event.
AB - The 2020 Olympic/Paralympic Games have been postponed to 2021, due to the COVID-19 pandemic. We developed a model that integrated source–environment–receptor pathways to evaluate how preventive efforts can reduce the infection risk among spectators at the opening ceremony of Tokyo Olympic Games. We simulated viral loads of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emitted from infectors through talking/coughing/sneezing and modeled temporal environmental behaviors, including virus inactivation and transfer. We performed Monte Carlo simulations to estimate the expected number of newly infected individuals with and without preventive measures, yielding the crude probability of a spectator being an infector among the 60,000 people expected to attend the opening ceremony. Two indicators, i.e., the expected number of newly infected individuals and the newly infected individuals per infector entry, were proposed to demonstrate the extent of achievable infection risk reduction levels by implementing possible preventive measures. A no-prevention scenario produced 1.5–1.7 newly infected individuals per infector entry, whereas a combination of cooperative preventive measures by organizers and the spectators achieved a 99% risk reduction, corresponding to 0.009–0.012 newly infected individuals per infector entry. The expected number of newly infected individuals was calculated as 0.005 for the combination of cooperative preventive scenarios with the crude probability of a spectator being an infector of 1 × 10−5. Based on our estimates, a combination of cooperative preventions between organizers and spectators is required to prevent a viral spread at the Tokyo Olympic/Paralympic Games. Further, under the assumption that society accepts < 10 newly infected persons traced to events held during the entire Olympic/Paralympic Games, we propose a crude probability of infectors of < 5 × 10−5 as a benchmark for the suppression of the infection. This is the first study to develop a model that can assess the infection risk among spectators due to exposure pathways at a mass gathering event.
KW - COVID-19
KW - Infection risk
KW - Mass gathering event
KW - Solution-focused risk assessment
KW - Tokyo 2020 Olympic/Paralympic Games
UR - http://www.scopus.com/inward/record.url?scp=85104365256&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85104365256&partnerID=8YFLogxK
U2 - 10.1016/j.mran.2021.100162
DO - 10.1016/j.mran.2021.100162
M3 - Article
AN - SCOPUS:85104365256
VL - 19
JO - Microbial Risk Analysis
JF - Microbial Risk Analysis
SN - 2352-3522
M1 - 100162
ER -
