The World Health Organization (WHO) has published new guidance to prevent heat-related illnesses at mass gatherings, such as major sporting, religious, and cultural events. According to the WHO, heat-related illness at mass gatherings has become a significant public health and operational risk, affecting spectators, attendees, volunteers, and workers. The guidance aims to provide event organizers and host countries with the necessary tools to anticipate and manage heat-related health risks. This move comes as heat-related deaths have increased by an estimated 63% since the 1990s.
The WHO's evidence review, covering studies published between 1980 and 2025, documented nearly half a million medical encounters at mass gatherings, including more than 22,000 heat-related illnesses. The review also showed that when on-site medical systems are well-organized, more than 90% of patients can be treated at event venues, substantially reducing demand on local hospitals and ambulance services. Dr. Chikwe Ihekweazu, Executive Director of the WHO Health Emergencies Programme, emphasized that extreme heat is an increasing threat to health, safety, and operational continuity in mass gatherings.
Mass gatherings can amplify heat risks in several ways, including long periods outdoors with exposure to heat and sun, dense crowds, limited access to safe water, travel-related stress, unfamiliarity with local climatic conditions, and competing demands on health services. According to the Intergovernmental Panel on Climate Change (IPCC), hot extremes, including heatwaves, have become more frequent and more intense across most land regions since the 1950s, mainly as a result of climate change. The IPCC also projects further increases in the frequency and intensity of hot extremes with every additional increment of global warming.
The WHO's new guidance, titled "Prevention and management of heat-related illness at mass gatherings," provides a set of resources to help host countries and event organizers better anticipate and manage heat-related health risks. The guidance focuses on spectators, attendees, volunteers, and workers and is intended to complement WHO's guidance on heat-health action plans as well as existing national heat-health action plans, occupational health and safety requirements, emergency preparedness arrangements, and clinical guidance.
The most effective approaches to preventing heat-related illnesses at mass gatherings combine multiple measures, including accessible and safe drinking water and toilets, cooling infrastructure, schedule adjustments, crowd-flow management, workforce protection measures, public communication, real-time surveillance, and well-prepared on-site medical services. The guidance emphasizes a whole-of-event approach, recognizing that factors such as venue design, crowd management, water and sanitation, transport, security, communications, and workforce management all influence access to cooling, safe water, and timely medical care.
The WHO is calling on governments, event organizers, and partners to integrate heat risk management into health planning, preparedness, and operations for mass gatherings worldwide. This move aims to reduce immediate harm and support safer, more resilient event planning in a warming world. The guidance covers the full event cycle and should be integrated into broader emergency preparedness and all-hazards risk management.
The new guidance comes as an estimated 546,000 deaths occur annually due to heat-related illnesses, with an average of 546,000 deaths occurring annually between 2012 and 2021. The WHO's guidance aims to address the increasing threat of extreme heat to health, safety, and operational continuity in mass gatherings, and to support event organizers and host countries in creating safer and more resilient events.
Key points
- The WHO's new guidance provides a set of resources to help host countries and event organizers better anticipate and manage heat-related health risks at mass gatherings.
- The guidance emphasizes a whole-of-event approach, recognizing that multiple factors influence access to cooling, safe water, and timely medical care.
- The WHO is calling on governments, event organizers, and partners to integrate heat risk management into health planning, preparedness, and operations for mass gatherings worldwide.
