Maximum proportion of masks worn: Collaborative efforts in Japanese professional football.

Mass gathering events in Japan have gradually mitigated their novel coronavirus disease (COVID-19) control regulations, along with a minimum infection risk. The Japan Professional Football League (J.League) conducted pilot surveys on holding events with chant cheers. In this commentary, we introduce the collaborative efforts based on scientific knowledge among experts, J.League, and their fans. We performed risk assessment in advance, by updating a previously developed model. We further observed the average proportion of masks worn, chant cheering time of participants, and CO2 levels in the stand. The number of new COVID-19 cases in an event with 5,000 chant cheering participants and 35,000 non-chant cheering participants was estimated to be 1.02 times of an event, with 40,000 non-chant cheering participants. The average proportion of masks worn during the game was 98.9 %, for chant cheer participants. The chant cheering participants spent 50.0-51.1 % of their time chant cheering. Monitored average CO2 levels were ≤ 540 ppm, suggesting high ventilation rates in the stand. The high proportion of masks worn represents the willingness of norm-conscious fans to cooperate in regular recovery of the sport. This has proved to be one of the successful models for future mass gathering events.

Assessment of COVID-19 risk and prevention effectiveness among spectators of mass gathering events.

There is a need to evaluate and minimize the risk of novel coronavirus infections at mass gathering events, such as sports. In particular, to consider how to hold mass gathering events, it is important to clarify how the local infection prevalence, the number of spectators, the capacity proportion, and the implementation of preventions affect the infection risk. In this study, we used an environmental exposure model to analyze the relationship between infection risk and infection prevalence, the number of spectators, and the capacity proportion at mass gathering events in football and baseball games. In addition to assessing risk reduction through the implementation of various preventive measures, we assessed how face-mask-wearing proportion affects infection risk. Furthermore, the model was applied to estimate the number of infectors who entered the stadium and the number of newly infected individuals, and to compare them with actual reported cases. The model analysis revealed an 86-95% reduction in the infection risk due to the implementation of face-mask wearing and hand washing. Under conditions in which vaccine effectiveness was 20% and 80%, the risk reduction rates of infection among vaccinated spectators were 36% and 96%, respectively. Among the individual measures, face-mask wearing was particularly effective, and the infection risk increased as the face-mask-wearing proportion decreased. A linear relationship was observed between infection risk at mass gathering events and the infection prevalence. Furthermore, the number of newly infected individuals was also dependent on the number of spectators and the capacity proportion independent of the infection prevalence, confirming the importance of considering spectator capacity in infection risk management. These results highlight that it is beneficial for organisers to ensure prevention compliance and to mitigate or limit the number of spectators according to the prevalence of local infection. Both the estimated and reported numbers of newly infected individuals after the events were small, below 10 per 3-4 million spectators, despite a small gap between these numbers.

Empirical research on the utility of a preparation manual for a disaster medical response drill.

PURPOSE: It is difficult for emergency physicians to plan and execute a disaster medical response drill while conducting their daily work activities. Readily available drill preparation manuals are therefore essential, alongside assessment methods to ensure quality. Here, we propose email text analysis as a manual assessment method, and investigate its validity. METHODS: The preparation status of two similar large-scale disaster medical response drills were compared. All email texts exchanged during the preparation stage were analyzed, and frequently appearing words (quality element) and word counts (quantity element) were compared between Drill 1, which was organized without a manual, and Drill 2, organized with a manual. RESULTS: Word frequency analysis revealed that the key components of the manual (visualization of necessary work, preparation of documents in a certain format, and clarification of aims of the drill) contributed to the effectiveness of the preparation process for Drill 2. Furthermore, work volume during the preparation for Drill 2 was decreased by 41.9% from that during the preparation for Drill 1. CONCLUSION: Preparation of a high-quality manual is crucial so that emergency physicians can plan and execute a disaster medical response drill. Email text analysis can serve as an objective method assessing the quality of manuals.