COVID-19 risk assessment at the opening ceremony of the Tokyo 2020 Olympic Games

Autor: Yoshitaka Nishikawa, Yurie Kobashi, Akihiko Ozaki, Kenkichi Fujii, Wataru Naito, Tomoaki Okuda, Seiya Imoto, Masaya M. Saito, Fuminari Miura, Yuzo Shimazu, Tetsuo Yasutaka, Masaaki Kitajima, Toyoaki Sawano, Masaharu Tsubokura, Yuichi Iwasaki, Michio Murakami, Kyoko Ono, Toshiki Abe, Sumire Sorano, Kotoe Katayama
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Microbial Risk Analysis
ISSN: 2352-3530
2352-3522
Popis: 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.
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Databáze: OpenAIRE
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