Introduction: In the context of mass gatherings, event-based surveillance (EBS) plays a critical role in detecting public health threats in the host country, the home countries of attendees, and neighboring nations. During the Paris 2024 Olympics and Paralympic Games, the World Health Organization Health Emergency Program conducted tailored public health intelligence activities, including enhanced EBS, to monitor potential health risks related to the event. Methods: Using an all-hazards approach, priority diseases and hazards were identified based on WHO’s EBS activities for previous mass gathering events, the French government’s priority disease list, and hazards flagged by WHO as relevant in the European Region. EBS covering domestic and global health signals was conducted using the Epidemic Intelligence from Open Sources (EIOS) platform, a leading initiative for open-source intelligence. This surveillance effort spanned from two weeks before the Olympics to two weeks after the Paralympics, covering 24 hours. Signals were triaged and assessed for their public health impact and potential risk to the Games. The risk assessment outcomes were shared daily with the French government and key stakeholders. Results: Between July 12 and September 20, 2024, a total of 42,870 raw signals were scanned and triangulated, with 49 (0.1%) signals assessed and triaged for potential public health risks. Of these, 16 were further assessed to have a potential impact on the Games, with respiratory diseases, particularly COVID-19, accounting for 44% (n = 7), followed by soil- and water-borne diseases (25%, n = 4). Conclusion: While several signals with potential public health impact on the Games were flagged, none were assessed as requiring notification through the International Health Regulations (2005) mechanism. The integration of tailored EBS into mass gatherings is crucial for identifying hazards, assessing risks, implementing precautionary measures, and supporting decision-making, all of which are key to making events safer for public health.
Sodagar et al. (Sun,) studied this question.