Preparation for mass gathering events from the perspective of a non-host country: the experience of Japan during the 2018 PyeongChang Olympics and Paralympic Winter Games

@#The World Health Organization recommends that countries or organizations that host mass gatherings plan ahead and prepare for possible public health events to ensure a safe environment for local residents, participants and travellers.1 Public health events during mass gatherings can also affect non-host countries. There are numerous reports of the spread of infectious diseases by travellers returning from mass gatherings,2 which can potentially pose the risk of an outbreak of new infectious diseases to travellers’ home countries. With more frequent travel across borders, it is prudent that non-host countries prepare for mass gathering events.