Large gatherings such as concerts, sporting events, religious ceremonies and demonstrations are an essential part of a society’s vibrant public life and traditions, but they also carry risks. Participants can suffer from stress-related illnesses or sustained exposure to extreme temperatures, and even be injured or die as a result of uncontrolled crowd behaviors.
A 2012 metastudy published in The Lancet Infectious Diseases, “Non-Communicable Health Risks During Mass Gatherings,” examines the broader health risks associated with mass public gatherings. The researchers, based at the University of Zurich, the University of Texas School of Public Health and other institutions, looked at data on non-communicable threats such as stress-related cardiac episodes, stampedes and terrorist attacks, and proposed mitigation strategies.
Key study findings include:
Human stampedes are the leading cause of harm during mass gatherings, with more than 7,000 fatalities and 14,000 injuries worldwide reported between 1980 and 2007. Stampedes can be triggered by panicked responses to real or imagined dangers. “For example, a stampede resulting in about 1,000 deaths in Iraq in 2005 was triggered by the false rumour of a suicide bomber.”
Weather extremes can cause illnesses such as heatstroke and hypothermia. Warm, humid conditions are considered to be the most dangerous: In 1985, extremely hot temperatures in Mecca were responsible for more than 1,000 deaths from heatstroke.
Sporting events can result in elevated stress levels for spectators and the onset of cardiovascular problems. “During the World Cup in Germany in 2006, the incidence of cardiac emergencies in the host population watching its own team was 2.66 times higher than during a control period…. Cardiac arrest was reported to be fairly frequent in the soccer stadiums.”
Other risk factors at mass gatherings include whether the event takes place in a developing country, the level of crowding and the prevalence of drugs or alcohol. Particular at-risk populations include women, the very young and the elderly.
Despite the dangers, during stampede or evacuation scenarios “social order does not break down, even when individuals fear for their lives…. [Participants] behaved in a civilised, orderly and calm manner, even though they realised the extreme danger they were in.”
Proposed measures to better manage mass gatherings include creating an infrastructure to mobilize a large-scale response, providing appropriate interventions to prevent heat-related illness and providing emergency medical care throughout gatherings.
The researchers note that while terrorist acts targeting a mass gathering are rarely successful, “health outcomes associated with terrorism are not restricted to the effect of successful attacks. [Mass gatherings] are settings for panic, rumour, and hoax, and bomb scares have been the source of lethal stampedes.”