Travel to Mass Gatherings


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

Characteristics of Mass Gatherings

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 a political protest; 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 the host country, available infrastructure, the local environment, and the adequacy of security arrangements.
  • Venue: Facilities vary widely, and events may be held indoors or outdoors. Facilities, including food, water, and sanitation, may be of varying quality.
  • Purpose: Mass gatherings can be political, religious, social, or athletic; the purpose of an event can affect the activities and mood of participants.
  • Size: Densely packed crowds may facilitate disease spread or induce riots or crowd crush disasters.
  • Participants: Attendees may represent a unique demographic or may vary by features such as sex or age.
  • Duration: The longer an event lasts, the more likely local resources will become strained.
  • Timing: Mass gatherings and local capacity are affected by the timing of an event. Weather, heavy tourism, and other factors can affect the ability of a host to organize a safe mass gathering.
  • Activities: Understand the activities that the traveler may participate in: some may be risky or strenuous 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.

Health Concerns Related to Mass Gatherings

Existing medical conditions may be exacerbated during a mass gathering. Emergency medical services are often involved in preparations and are usually equipped to address acute medical conditions such as myocardial infarction and asthma. Conditions such as heat exhaustion, dehydration, hypothermia, or sunburn are usually handled on site as well.

Catastrophic incidents are of particular concern with mass gatherings. Numerous casualties at mass gatherings have occurred as the result of poor crowd management, structural collapses, fires, and violence.

Mass gathering attendees also are at risk for infectious disease. Previous mass gatherings have been associated with outbreaks of influenza, meningococcal disease, and norovirus. Mass gatherings also have implications for global health security. Travelers to mass gatherings may import diseases to a host site as well as spread disease when they return home.

Guidance for Clinicians

Assessing Risk

  • Ask travelers about their itineraries and activities. Verify a traveler’s itinerary to identify risks beyond those associated with the event. Patients may add side trips or extend travel beyond the mass gathering.
  • Consider your patient’s unique characteristics. Chronic health conditions may be exacerbated by activities at 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 participants in the Hajj, the Islamic pilgrimage to Mecca, 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. After the emergence of the Middle East respiratory syndrome (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 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.

Guidance for Travelers

  • 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 your 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 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 in the event of serious legal, medical, or financial difficulties while traveling. In the event of an emergency at home, STEP can also help friends and family 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 pretravel consultation.
  • Visit the CDC Travelers’ Health website at Learn more about specific destinations and view any travel notices for your destination.


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Joanna Gaines, Gary W. Brunette