Mass Gathering Medicine: Lessons from the Hajj


This year’s Hajj – the annual Islamic pilgrimage to Mecca –has been making headlines as one of the deadliest in history. Between a crane collapse and a deadly stampede, there were over 800 traumatic deaths before the end of September. Already one of the most studied mass-gatherings in the world, this year’s events put special focus on the need for advanced mass gathering preparedness. Here are a few lessons that we’ve learned already.

Every year, more mass gatherings occur throughout the United States and emergency physicians (EPs) are often at the front lines of response to these events. Mass Gathering Medicine (MGM) is the field of study that analyzes the management of these events in order to employ strategies to effectively enhance the delivery of health care. And it’s a good thing, because poorly managed mass gatherings can have significant morbidity and mortality. In the past, inadequate crowd control has resulted in deadly stampedes and sub-par sanitation facilities have caused mass outbreaks of communicable disease [1,2,3].

Given this increasing reality, emergency physicians need to ground themselves in MGM principles and be prepared to take an active role to ensure adequate preparation and staffing of mass gatherings within their facility’s catchment area.


Interestingly, much of the MGM literature is based on international data. Examining strategies implemented in countries with extensive experience in mass gatherings can provide essential framework for mass gatherings here in the US. The Hajj in Saudi Arabia is an annual five-day gathering that amasses millions of pilgrims in and around Mecca. Hajj often takes place in punishing heat, with many pilgrims arriving by foot, so the potential for illness and injury is great. What makes the Hajj so unique for physicians is that it is the oldest studied mass gathering, with reports on medical care and disease outbreaks appearing in the medical literature since the 1800s [4].

The Hajj (Arabic for ‘pilgrimage’) is the fifth pillar of Islam and is considered obligatory for those with the financial and physical means to complete it. The number of pilgrims completing the journey between five holy sites in Islam has grown steadily since its inception over thirteen hundred years ago [5]. Travelers perform this pilgrimage during the final month of the Islamic (lunar) calendar, traveling to a new site each day over several kilometers of desert. Travel by bus or rail is possible, however demand overwhelms capacity each year and many travelers undertake the pilgrimage on foot [6].

Since pilgrims originate from almost 200 nations, health care organizers have to employ a robust surveillance system with frequent updates. After deadly outbreaks of meningococcemia during the 2000 Hajj, health organizers devoted significant resources to surveilling communicable disease threats, which could have devastating impacts on the crowded confines of the Hajj. From this surveillance arose a requirement of meningococcal, yellow fever, and polio vaccinations for pilgrims who travel from countries where these diseases are prevalent [7]. The Hajj is the only mass gathering that requires vaccinations, though certain countries require yellow fever vaccinations in any travelers from endemic regions.


Recent global public health threats such as MERS-CoV and Ebola have tested Saudi Arabia’s surveillance systems. Hajj authorities responded to early MERS-CoV outbreak mortality by aggressively advising vulnerable populations to avoid the Hajj and disseminating information about hand hygiene, masks, and isolation for persons with respiratory symptoms [6,7]. Two MERS-CoV hospital admissions and zero associated deaths were reported amongst Hajj visitors during the 2014 pilgrimage [8]. During the recent Ebola epidemic in 2014, the Hajj health ministries prohibited travel from Liberia, Sierra Leone, and Guinea – the three nations from where the vast majority of disease burden originated [9]. No cases of Ebola were reported during the 2014 Hajj.

The Hajj’s sophisticated healthcare system is overseen by a dedicated subsection of the Saudi Arabian Ministry of Health. This includes 25 hospitals, more than a 100 health centers including emergency health centers, and 100 ambulances. A comprehensive public health surveillance system enabled the Hajj organizers to recognize heat stroke as a significant cause of morbidity, which was noticeably reduced after cold water, sun cover, and air misters were provided along pilgrimage routes [6,10,11].

Other incidents provided the impetus for Hajj organizers to redesign portions of the pilgrimage to minimize risk to pilgrims. In 1975 and 1997, cooking stoves caused tent colony fires that resulted in hundreds of deaths and thousands of injuries. All tents have subsequently been replaced with a permanent city of fireproof tents designed and used solely for the Hajj, complete with a fire-suppression system. Personal tents and cooking within tents are no longer permitted [6].

Stampedes, in particular, have been the cause of multiple mass casualty incidents (MCIs) at the Hajj resulting in thousands of fatalities. In 1990, 1,426 pilgrims were killed in a tunnel stampede at Mecca. Hajj attendance has steadily grown, and multiple stampedes in subsequent years have resulted in hundreds more deaths. In response, event organizers arranged for camera installations along the Hajj route. Information gleaned from this surveillance led to the construction of a multi-story bridge that can carry millions of pilgrims simultaneously, as well as a redesign of structures and spaces integral to Hajj rituals [12]. Crowd control has vastly improved with a reduction of crowd convergence points through enforcement of unidirectional flow, staggered entry, and multiple entry/exit points. Since these measures have been enacted, no stampedes have been reported. However, just last month in September 2015, a large crane collapsed on the Grand Mosque in Mecca killing 107 people and wounding scores more. A severe rainstorm and strong winds are believed to  have caused the collapse. These tragedies underscore the vital role of medical preparedness to efficiently respond to the injured and improve system-based errors learned from these MCIs.


While masses typically gather in the US for different purposes than the religious mass gathering discussed here, with radically different psychosocial factors at play [14], the Hajj remains the best studied and arguably best MGM preparedness effort in the world. Studies reveal that the challenges faced by the Hajj are in fact the same challenges facing mass gatherings the world over: crowd control, ingress/egress and event site access, control of infectious disease transmission, fire/stampede prevention, medical preparedness and situational response [15].

Here are a few key lessons that American physicians can learn from this, the most-studied mass gathering in history, on how to enhance MGM preparedness efforts in the United States:

  • All aspects of preparedness affect medical usage rates (MUR). Without adequate crowd control, safety and security protocols (including fire prevention), waste and sanitation facilities, potable drinking water/food, and good communication to attendees and between staff members, MCIs can occur that will overwhelm healthcare resources.
    Utilize harm-reduction public service announcements (PSA) via multiple avenues, including websites and social media, to communicate vital information to attendees.
  • Mass gatherings have a high incidence of environment-specific medical challenges, from zoonotic and vector-borne diseases to heat exhaustion. EPs should be knowledgeable about environmental challenges unique to their catchment area, and suggest simple preventative measures for these.
    Consider provision of sun cover, distribution of free potable water, and frequent watering of event grounds, especially cement, when attendees are exposed to hot, humid environments for prolonged periods of time.
    Be aware of potential zoonoses and vector-borne diseases in the area and push for protection of bathing/cooking/drinking water sources from contamination, removal of standing water, and liberal pesticide use to ensure adequate vector control [16].
  • In planning the layout of event grounds and resources, consider the distribution of attendees over the course of the event and organize necessary facilities accordingly.
    The geographic positioning of medical facilities and providers is vital, and suboptimal positioning can have significant deleterious effects. Pay special attention to ensuring clear pathways of ingress and egress for first responders/ambulances as this has repeatedly proven a challenge for mass gatherings of all types.
    Crowd control is of critical importance, as trauma from stampedes is a significant cause of MCIs and increases high acuity MUR. Reduce points of crowd convergence by creating spaces with unidirectional flow, staggered entry, and dedicated entry and exit points. Exit points should be twice as large as entry points.
  • Medical complaints are largely low acuity at mass gatherings, with a small percentage of high acuity, resource intensive utilization. Prepare accordingly.
  • Multiple critical care transporting units are likely unnecessary. While access to aeromedical transport may be essential, the majority of providers will treat low acuity conditions such as musculoskeletal complaints, lacerations, asthma, and urinary tract infections [17].
  • Event organizers and local health officials should invest time and resources in collecting data from their event to aid preparation for future events and implementing a surveillance system to rapidly identify adverse health events.
  • Most importantly, advocate for your healthcare organization, your community, and the potential patients resulting from a nearby mass gathering. Seek out event organizers and ensure that mass gathering medicine preparedness is optimal. Your ED will likely be overwhelmed if it’s not!
    Do not first become aware of a nearby mass gathering when the injured patients start to arrive in your ED.


  1. Botelho-Nevers E, Gautret P. Outbreaks associated to large open air festivals, including music festivals, 1980 to 2012. Euro Surveill. 2013;18(11):pii=20426.
  2. Greenough PG. The Kumbh Mela stampede: disaster preparedness must bridge jurisdictions. BMJ. 2013 May 20;346:f3254. doi: 10.1136/bmj.f3254.
  3. Lee LA, Ostroff SM, McGee HB, Johnson DR, Downes FP, Cameron DN, Bean NH, Griffin PM. An outbreak of shigellosis at an outdoor music festival. Am J Epidemiol. 1991 Mar 15;133(6):608-15.
  4. Memish ZA, Stephens GM, Steffen R, Ahmed QA. Emergence of medicine for mass gatherings: lessons from the Hajj. Lancet Infect Dis. 2012 Jan;12(1):56-65. doi: 10.1016/S1473-3099(11)70337-1.
  5. Butt R. Mecca makeover: how the hajj has become big business for Saudi Arabia. The Guardian. 2010 14 Nov;
  6. Bowron CS, Salahudin MM. Chapter 4: Select Destinations The Middle East and North Africa. Saudi Arabia: Hajj Pilgrimage. CDC Health Information for International Travel: The Yellow Book 2016.
  7. Al-Tawfiq JA, Memish ZA. Mass gathering medicine: 2014 Hajj and Umra preparation as a leading example. Int J Infect Dis. 2014 Oct;27:26-31. doi: 10.1016/j.ijid.2014.07.001.
  8. Aberle JH, Popow-Kraupp T, Kreidl P, Laferl H, Heinz FX, Aberle SW. Influenza A and B Viruses but Not MERS-CoV in Hajj Pilgrims, Austria, 2014.
    Emerg Infect Dis. 2015 Apr;21(4):726-7. doi: 10.3201/eid2104.141745.
  9. Sheikh A. Saudi Arabia bans Ebola-stricken countries from hajj pilgrimage. Oct 2 2014.
  10. Ahmed QA1, Arabi YM, Memish ZA. Health risks at the Hajj. Lancet. 2006 Mar 25;367(9515):1008-15.
  11. Gabal MS, Khadiga AS. Pattern of heat stroke and heat exhaustion among pilgrims over 20 years (1982-2001). J Egypt Public Health Assoc 2003.
  12. Ball P. Crowd researchers make pilgrimage safer. Nature. 2007 Jan 19. doi:10.1038/news070115-13
  13. Johansson A, Batty M, Hayashi K, Al Bar O, Marcozzi D, Memish ZA.
    Crowd and environmental management during mass gatherings. Lancet Infect Dis. 2012 Feb;12(2):150-6. doi: 10.1016/S1473-3099(11)70287-0.
  14. Hutton A, Brown S, Verdonk N. Exploring culture: audience predispositions and consequent effects on audience behavior in a mass-gathering setting. Prehosp Disaster Med. 2013 Jun;28(3):292-7. doi: 10.1017/S1049023X13000228.
  15. Soomaroo L, Murray V. Disasters at mass gatherings: lessons from history. PLoS Curr. 2012 Feb 2;4:RRN1301.
  16. Abubakar I, Gautret P, Brunette GW, Blumberg L, Johnson D, Poumerol G, Memish ZA, Barbeschi M, Khan AS. Global perspectives for prevention of infectious diseases associated with mass gatherings. Lancet Infect Dis. 2012 Jan;12(1):66-74. doi: 10.1016/S1473-3099(11)70246-8.
  17. Thompson JM, Savoia G, Powell G, Challis EB, Law P. Level of medical care required for mass gatherings: the XV Winter Olympic Games in Calgary, Canada. Ann Emerg Med. 1991 Apr;20(4):385-90.


Sonali Ganguly, MD, MA is a senior EM  resident at Maimonides Medical Center. She has staffed multiple EDM festivals and other mass gatherings.

Matt S. Friedman, MD is a board certified EMS and Emergency Medicine physician. He completed an EMS fellowship with the Fire Department City of New York (FDNY). He is currently the Associate Medical Director of Prehospital Care at Maimonides Medical Center in Brooklyn, NY. He also serves as the Lead House Physician for Yankee Stadium, Madison Square Garden and the US Open. Dr. Friedman is the acting medical director for numerous annual mass gatherings and large music festivals in NYC. 


Leave A Reply