Global warming and the Summer Olympic and Paralympic games: a perspective from the Tokyo 2020 Games

The Tokyo 2020 Olympic and Paralympic Games provided a significant opportunity to consider global warming as an issue to be seriously addressed to run the safe and fair games in the era of climate change. As the global temperature continuously rises and extreme hot-weather events increase in frequency and intensity, the future summer Olympic and Paralympic games will need to deal with the heat by applying thorough and appropriate countermeasures. In the recent decades, many mitigation measures to protect athletes from heat have been rapidly discussed by the sports community, including countermeasures to hold games at times and places with moderate temperature and climatic risk assessments with Wet Bulb Globe Temperature (WBGT) during the games. However, the excessive heat conditions in the Tokyo 2020 Games affected not only athletes, but also all people concerned the events. While deliberate considerations by organizers had been given to mitigate extraordinary heat, the evaluations of these measures and epidemiological analyses of risk factors of patients must be further enhanced to develop efficient measures for the future. Therefore, we discussed the underlying climate-related problems of the summer Olympic and Paralympic Games in view of what we had experienced in the Tokyo 2020 Games. Facing with emerging global warming, future intervention against heat in the summer Olympic and Paralympic games will need to integrate systematic disease surveillance and evaluation of intervention with an effective combination with the approaches previously conducted. The Tokyo 2020 Games is a wake-up call to accelerate the public health measures towards the creeping global warming.

The impact of temperature on the transmission potential and virulence of COVID-19 in Tokyo, Japan

BackgroundAssessing the impact of temperature on COVID-19 epidemiology is critical for implementing non-pharmaceutical interventions. However, few studies have accounted for the nature of contagious diseases, i.e., their dependent happenings. AimWe aimed to quantify the impact of temperature on the transmissibility and virulence of COVID-19 in Tokyo, Japan. We employed two epidemiological measurements of transmissibility and severity: the effective reproduction number (Rt) and case fatality risk (CFR). MethodsWe used empirical surveillance data and meteorological data in Tokyo to estimate the Rt and time-delay adjusted CFR and to subsequently assess the nonlinear and delay effect of temperature on Rt and time-delay adjusted CFR. ResultsFor Rt at low temperatures, the cumulative relative risk (RR) at first temperature percentile (3.3{degrees}C) was 1.3 (95% confidence interval (CI): 1.1-1.7). As for the virulence to humans, moderate cold temperatures were associated with higher CFR, and CFR also increased as the temperature rose. The cumulative RR at the 10th and 99th percentiles of temperature (5.8{degrees}C and 30.8{degrees}C) for CFR were 3.5 (95%CI: 1.3-10) and 6.4 (95%CI: 4.1-10.1). ConclusionsThis study provided information on the effects of temperature on the COVID-19 epidemiology using Rt and time-delay adjusted CFR. Our results suggest the importance to take precautions to avoid infection in both cold and warm seasons to avoid severe cases of COVID-19. The results and proposed framework will also help in assessing possible seasonal course of COVID-19 in the future.