Minimised SARS-CoV-2 transmission during Tokyo 2020 Olympic and Paralympic Games: insights from enhanced integrated surveillance, Japan, July to September 2021
Munehisa Fukusumi, Keiko Tsukada, Kanako Otani, Masato Yamauchi, Yoshiyuki Sugishita, Chiaki Ikenoue, Tsuyoshi Sekizuka, Tomoe Shimada, Taro Kamigaki, Motoi Suzuki, Tomimasa Sunagawa, Makoto Kuroda, Tomoya SaitoBACKGROUND
Amid the COVID-19 pandemic, stringent public health measures were taken during the Tokyo 2020 Olympic and Paralympic Games (Tokyo 2020).
AIM
We describe SARS-CoV-2 transmission among Games participants and in-person contributors (GPIPC)s.
METHODS
Tokyo 2020-related SARS-CoV-2 infection cases were individuals linked to the event, testing positive for the virus between 1 July−19 September 2021, reported to the Tokyo Metropolitan Government. Attack rates among athletes and team officials were determined. Enhanced case-based surveillance integrating genomic sequencing data supported viral spread investigations among various GPIPC groups.
RESULTS
A total 804 cases (median age: 35 years, interquartile range (IQR): 27–45; 194 female/610 male) were reported. Among athletes and team officials, attack rates were 0.6% (65/11,400) in Olympic Games and 0.6% (30/4,800) in Paralympic Games. These 95 infections concerned mainly overseas travellers (n = 92), 85 of whom were diagnosed within 14 days of arrival in Japan. Among the 804 cases, whole-genome sequencing data were obtained for 304 (median age: 38 years, IQR: 29–47; 67 female/237 male) with sufficient viral load (as indicated by RT-PCR Cq ≤ 32), including 79% (75/95) of athletes and team officials cases, 74% (131/176) of Games’ organisers and media cases, and ˂ 20% (98/533) of remaining cases. Delta variants dominated (94%; 285/304), with domestic (AY.29 lineage) Delta strains prominent among Delta-variant-affected resident cases (96%; 104/108) and Games’ organisers and media cases diagnosed ≥ 15 days after entering Japan (97%; 63/65). Overseas Delta strains mostly affected travellers within 14 days of entry, particularly athletes and team officials (97%; 66/68) and Games’ organisers and media (29/34).
CONCLUSION
Multilayered-risk-reduction measures likely minimised SARS-CoV-2 transmission to athletes.