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Chapter 8 Advising Travelers with Specific Needs

Travel to Mass Gatherings

Joanna Gaines, Gary W. Brunette


Mass gatherings are typically defined as a large number of people (ranging from 1,000 to >25,000) at a specific location, for a specific purpose, for a defined time frame. More practically speaking, a mass gathering can be thought of as any gathering of people that is large enough to strain local resources. Travelers to mass gatherings face unique risks because these events are associated with increased infectious disease transmission due to the influx of attendees, crowding at venues, poor hygiene from temporary food and sanitation facilities, and challenging security situations.


Medical providers preparing travelers and travelers themselves should understand the characteristics of any mass gathering a patient will attend. These events can be spontaneous, such as the 2013 funeral for Nelson Mandela, which was attended by thousands from around the world; others are planned events. Some mass gatherings regularly occur at different locations, such as the Olympic Games or the FIFA World Cup, while others recur in the same location, such as the Hajj or Wimbledon. Mass gatherings can be effectively described in terms of their location, venue, purpose, size, participants, duration, timing, activities, and capacity.

  • Location: Factors to consider include identifying the host, what local infrastructure is like, what the environment is like, and whether or not security will be adequate.
  • Venue: Facilities vary widely, and events may be held indoors or outdoors. The venue’s facilities, including food, water, and sanitation, may be of varying quality. Some mass gatherings are also mobile, where attendees move from one place to another, such as during a pilgrimage.
  • Purpose: Understanding why people will attend an event is important. Mass gatherings can be political, religious, social, or athletic; the purpose of an event can affect the activities and mood of participants.
  • Size: Organizers must be prepared to manage large crowds, and densely packed crowds may facilitate disease spread or may promote problems such as riots, stampedes, and resulting injuries.
  • Participants: Attendees may represent a unique demographic or may vary by features such as sex or age.
  • Duration: The longer an event lasts, the higher the likelihood that local resources will become strained.
  • Timing: Mass gatherings and local capacity are affected by the timing of an event. Weather, as well as factors such as high tourist season, can affect the ability of a host to organize a safe mass gathering.
  • Activities: Understand the activities that participants will be participating in: some activities may be risky or strenuous behaviors or may involve alcohol or drug use.
  • Capacity: Hosts differ in terms of their ability to detect, respond to, and prevent public health emergencies. Understanding what health outcomes have been previously associated with recurring mass gatherings can help travelers prepare for future events.


Mass gatherings pose a risk to attendees in the form of exacerbation of existing medical conditions, injuries, and the potential spread of infectious diseases. Emergency medical services are often involved in preparations for mass gatherings and are usually equipped to address acute medical conditions such as myocardial infarction and asthma. Conditions such as heat exhaustion, dehydration, hypothermia, or sunburn can also affect attendees and are usually handled on site.

Because of the possibility of a catastrophic incident, safety is of particular concern with mass gatherings. A number of casualties at mass gatherings have occurred as the result of poor crowd management, structural collapses, fires, and violence. Mass gathering attendees are also at risk for infectious disease. Previously, mass gatherings have been associated with outbreaks of influenza, meningococcal disease, and norovirus. Mass gatherings have implications for global health security. More than 2 million pilgrims attended the Hajj in 2009 during the H1N1 pandemic and in 2013 during the outbreak of Middle East respiratory syndrome (MERS) in the Arabian Peninsula. Travelers to mass gatherings may import diseases to a host site as well as spread disease upon their return home. In 2010, measles outbreaks in Germany were linked to travelers who had attended a mass gathering event in Taizé, France.


Clinicians can prepare travelers for the unique health risks associated with mass gatherings.

Assessing Risk:

  • Ask travelers about their itineraries and activities. Verify a traveler’s itinerary to identify additional risks beyond those associated with the event. Patients may add side trips or extend travel beyond the mass gathering. For example, if a patient indicates that he will be attending the 2016 Olympic Games in Rio de Janeiro, malaria prophylaxis and yellow fever vaccination would not be a consideration. However, if the traveler chooses to also visit the Amazon rainforest (where malaria and yellow fever are endemic) while in Brazil, he would be at risk. CDC’s Travelers’ Health website posts travel notices to educate travelers and medical providers about health issues associated with specific destinations (
  • Consider your patient’s unique characteristics. Chronic health conditions may be exacerbated by the activities associated with a mass gathering. Patients should ensure they have adequate supplies of medication for the duration of their trip as well as documentation for any prescriptions.

Mitigating Risk:

  • Identify requirements for mass gathering attendees beyond those required for entry to a country. For example, all pilgrims to the Hajj are required to have meningococcal vaccinations, whereas other travelers to Saudi Arabia are not required to have these.
  • Identify recommendations for attendees, as host sites may make additional recommendations on the basis of public health concerns. In response to the emergence in 2013 of MERS coronavirus, Saudi Arabia recommended that elderly or immunocompromised people delay their pilgrimage.
  • Educate travelers on preventive measures. These may include the use of insect repellent or advice on how to choose safe food and water from vendors. All travelers to mass gatherings should be educated on the importance of regular handwashing and the use of alcohol-based sanitizer when sanitation facilities are not available.
  • Visit the CDC’s Travelers’ Health website at This website is regularly updated with travel health notices; information may also be provided on mass gatherings such as the Hajj or Olympic Games.


  • Consult a travel medicine provider at least 4–6 weeks before the departure date. This should allow adequate time to receive most vaccinations. Discuss your itinerary and any planned activities with your provider so that he or she can make more accurate recommendations to ensure a traveler’s health and safety. If a travel medicine provider is not locally available, a primary care provider should be able to assist you with ensuring you have the adequate vaccinations and health information necessary.
  • Register travel plans with the Department of State’s Smart Traveler Enrollment Program (STEP) ( Travelers can subscribe for notifications on Travel Warnings, Travel Alerts, and other information for their specific destination(s), as well as ensure that the Department of State is aware of a traveler’s presence should they have serious legal, medical, or financial difficulties while traveling. In the event of an emergency at home, STEP can also help friends and family at home reach travelers abroad.
  • Ensure any existing medical conditions are well controlled before departure. Travelers should discuss their medical history with their medical provider during the pre-travel consultation.
  • Visit the CDC’s Travelers’ Health website at Learn more about specific destinations and view any travel notices for your destination.


  1. Abubakar I, Gautret P, Brunette GW, Blumberg L, Johnson D, Poumerol G, et al. Global perspectives for prevention of infectious diseases associated with mass gatherings. Lancet Infect Dis. 2012 Jan;12(1):66–74.
  2. Arbon P. Mass-gathering medicine: a review of the evidence and future directions for research. Prehosp Disaster Med. 2007 Mar–Apr;22(2):131–5.
  3. Emergency Management Australia. Safe and healthy mass gatherings: a health, medical and safety planning manual for public events. Fyshwick, Australia: Commonwealth of Australia; 1999.
  4. Lombardo JS, Sniegoski CA, Loschen WA, Westercamp M, Wade M, Dearth S, et al. Public health surveillance for mass gatherings. Johns Hopkins APL Technical Digest. 2008;27(4):1–9.
  5. McCloskey B, Endericks T. Learning from London 2012: a practical guide to public health and mass gatherings. London: Health Protection Agency; 2013 [cited 2014 Sep 24]. Available from:
  6. Milsten AM, Maguire BJ, Bissell RA, Seaman KG. Mass-gathering medical care: a review of the literature. Prehosp Disaster Med. 2002 Jul–Sep;17(3):151–62.
  7. Steffen R, Bouchama A, Johansson A, Dvorak J, Isla N, Smallwood C, et al. Non-communicable health risks during mass gatherings. Lancet Infect Dis. 2012 Feb;12(2):142–9.
  8. World Health Organization. Communicable disease alert and response for mass gatherings: key considerations. Geneva: World Health Organization; 2008 [cited 2014 Sep 24]. Available from: