Prevention and management of heat-related illness at mass gatherings: systematic reviews

Overview

Extreme heat is an increasingly important threat to health and operational continuity during mass gatherings. Climate change is increasing the frequency, duration and intensity of heat exposure, while high crowd density, prolonged outdoor activity, restricted movement, inadequate access to cooling areas or safe water, and diverse population vulnerabilities can amplify risk in event settings, particularly in urban contexts. Consequently, heat-related illness is no longer a peripheral planning issue. Rather, it is a core public health and service-delivery concern that can affect attendees, volunteers, and workers during mass gatherings and can challenge local health systems.

The report synthesizes findings from three systematic reviews conducted using “population, intervention, comparator and outcome” (PICO) frameworks. These reviews examined: cooling infrastructure, cool rest zones, cooling breaks and hydration practices; integrated early warning, crowd and capacity management, mobile applications and dynamic heat sensing; and visitors’ knowledge and perception, behaviour, vulnerability identification and wearable alerts.

This report provides an important evidence base to inform future World Health Organization guidance and support governments, health authorities and event organizers in reducing heat-related risk in a warming world.