Introduction
Globally, spontaneous mass gathering events (SMGEs) occur frequently. Spontaneous mass gathering events are unplanned assemblies of a significant number of people, often arising in response to specific triggers or circumstances. Unlike organized mass gathering events (MGEs), SMGEs are characterized by their rapid formation and lack of formal pre-planning. Examples of SMGEs may include situations such as civil unrest, riots, state funerals, and protests. Despite a lack of data pertaining to SMGEs, the provided and available statistics offer an indication of the frequency of SMGEs. Therefore, using protests as an example, there were more than 75 protests globally in the first 6 months of 2024 (January-June), and nearly 200 protests in 2023.1 These protests differ in context, highlighting the complexities of crowd motivation, which can significantly influence the dynamics of the event and the associated health system risks. Motivations can range from economic, political dissatisfaction, to concerns about corruption. The duration of some SMGEs can extend from days to months, and on some occasions to years. The public participation peak sizes in these SMGEs varied from less than 100 people to greater than 1,000,000 people.1 Recent examples of SMGEs around the world included COVID-19 lockdown protests, election-related protests, perceived police brutality protests, environmental protests, and/or economic pressure-related protests.Reference Zlobina and Gonzalez Vazquez2 Such SMGEs are said to gain public support as they attempt to address social problems by highlighting issues of concern, mostly related to social, legal, political, or institutional injustice.Reference Feinberg, Willer and Kovacheff3
The unpredictable nature of SMGEs poses significant challenges for health response, both from a public health and emergency health care perspective. Spontaneous mass gathering events may result in adverse health outcomes for attendees or those in the communities where events are being held. This is similar, but much increased, to the risk of more traditional MGEs.Reference Ranse, Lenson and Keene4 Traditionally, an MGE has been defined by the World Health Organization (WHO) as an occasion, either organized or spontaneous where the number of people attending is sufficient to strain the planning and response resources of the community, city, or nation hosting the event.5 Such MGEs are often diverse to include social, festival, religious, cultural, and/or sporting events. While an MGE presents a unique health response challenge, it could be argued that an SMGE is more complex within a higher threat environment due to its inherent unpredictability, potential for volatility, difficulties in accessing affected populations, and uncertain timelines.Reference Ranse, Hutton and Keene6
Planning for SMGEs, from a health perspective may focus on outcomes for patients and the safety of health staff. The planning for a response to an SMGE may occur either minutes, hours, or in rare circumstances, days prior to an event. This preparation timing depends on several factors, mostly related to the intelligence obtained from traditional or social media, other response agencies, the public, and/or the SMGE organisers.Reference Arkins, Liao and O’Donnell7 In addition to the challenges in timeframes for health planning response to SMGEs, the response is often made more complex by police, security, and/or military agencies leading, with limited health agency engagement.Reference Hawkins and Brice8 This is mostly related to the time from activation to response, whereby there is limited time to engage in interagency planning, which is crucial for effective health preparedness and response Despite these unique challenges, the specific needs for appropriate health preparedness and response in the context of SMGEs are not extensively discussed in the existing literature. This review will explore the unique health response challenges posed by SMGEs and propose strategies for improving health preparedness and response in these complex situations.
Aim
This review focuses on SMGEs and health service usage and outcomes. This review aims to determine the health planning, health provision, and health lessons learned from unplanned or SMGEs. This review was guided by the question: What are the health service delivery needs (concept) to care for patients (population) in SMGEs (context)?
Methods
Design
This scoping review followed the guidelines of PRISMA-ScR (Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews) checklist and explanation (see Supplementary Table 1).Reference Tricco, Lillie and Zarin9 This review was registered with PROSPERO (Reference: CRD42023462318).Reference Schiavo10
Data Collection
Papers were collected from various databases and search engines as artefacts of evidence to be included in this review. Databases and search engines used in this review included: CINAHL (EBSCO Information Services; Massachusetts, USA); PubMed (National Library of Medicine, USA); Science Direct (Elsevier; Amsterdam, Netherlands); and Scopus (Elsevier; Amsterdam, Netherlands). The search strategy included different combinations of Medical Subject Headings (MeSH) terms and keywords that are relevant to “mass gathering events,” “spontaneous events,” and “health services.” These keywords and MeSH terms are provided in Table 1. The detailed search strategy using these keywords and terms for each database is included in Supplementary File 1. The search was undertaken in February 2024 and was not limited by year. Additionally, the journal Prehospital and Disaster Medicine has a large publication base relating to MGEs. As such, the content page of this journal was reviewed for papers that would meet the inclusion criteria.
MeSH terms and keywords
* Wildcard search symbol
The titles and abstracts from the various databases were imported into Covidence® to allow for a blinded review process against the PRISMA-ScR guidelines. The title and abstract of each imported paper were screened by at least 2 authors. Any identified conflicts were then reviewed by an independent third author, who was blinded to the decisions of the first 2 authors. Papers were included if they reported on (i) real-world (actual) SMGEs, (ii) included health service delivery, and (iii) had information about health service usage such as first aid, ambulance transport, and hospital presentations. Papers were excluded if there were (i) editorials, (ii) conference abstracts, (iii) discussion papers, or (iv) papers of a theoretical nature. The same screening process to identify relevant papers was undertaken at the full-text review stage.
Data Analysis
Information was extracted from each paper and entered into a Microsoft Word 2018 table (Microsoft Corporation, Redmond, Washington, USA). This included the publication characteristics, spontaneous event characteristics (country of event: the country where the spontaneous event took place; year of event: the year when the spontaneous event took place; duration: the duration of the event; crowd number: the estimated number of people attending the event as participants/spectators); and responding agencies (such as ambulance, military, police, fire services) (see Table 2). Health service involvement and patient outcomes outlining what happened were deductively coded against the well-established 4 “S” surge capacity domains of staff, stuff/supplies, space, and systems.Reference Sheikhbardsiri, Raeisi, Nekoei-Moghadam and Rezaei11 Where staff relates to human resources or personnel; stuff/supplies relates to supplies, medicine, consumables, and equipment; space relates to facilities and physical infrastructure, congregation areas, and staging areas; and systems relates to procedures, policies, and processes (Table 3). The 4 “S” surge capacity domains are well-recognized in the disaster and humanitarian contexts to understand health resourcing. Since there are no equivalent frameworks in the MGE context, the 4 “S” surge capacity domains were used in a deductive manner to understand the health service delivery needs in SMGEs context. Additionally, lessons learned from each SMGE were deductively listed against the 4 surge capacity domains (Table 4).
Spontaneous event characteristics and responding agencies
Health service involvement and patient outcomes
ED, Emergency Departments; EMS, Emergency medical services; LEO, Law enforcement officer.
Lessons learned from health service involvement
ALS, Advanced life-support trained; ED, Emergency Departments; EMS, emergency medical services; LEO, law enforcement officer; MCI, Mass casualty incident.
* *This article is not about a single event but looks at a comparison of fatalities at protests
Results
In total, 10 papers were included in this review. Nine papers met the criteria for inclusion as identified through the Covidence® screening process. Additionally, 1 paper was identified in the search of the Prehospital and Disaster Medicine content page (see Figure 1). All papers were retrospectively reporting on SMGEs.
Modified PRISMA flow diagram.Reference Page, McKenzie and Bossuyt38
Spontaneous Event Characteristics and Responding Agencies
From the papers included the types of SMGEs varied, mostly related to riots or civil unrest (n = 4, 40%) or unplanned large parties, such as end-of-school celebrations or raves (n = 2, 20%) that required a response from the health care system (see Table 2). The duration of these SMGs varied from a couple of hours, typically for unplanned large parties, to many months for civil unrest. The size of crowds varied too, from smaller crowds of approximately 500 people for large unplanned parties, to larger crowds for civil unrest. However, exact or estimated crowd numbers were not consistently reported, and on some occasions completely omitted. It was common for the responding health agencies to be the local prehospital emergency medical services (EMS), alongside police from an enforcement and protective perspective.
Health Service Involvement and Patient Outcomes
Most papers (n = 9, 90%) reported on the prehospital response (see Table 3). Three papers (30%) included the impact on emergency department (ED) services,Reference Hawkins and Brice8, Reference Lee, Ooi and Phua12, Reference Solla, Carboni and Fernandez13 with 2 of these focusing only on the ED and hospital response. An analysis of health service involvement was undertaken against the 4 surge capacity domains. The staff were predominantly from an ambulance or EMS; however, their skills and number of staff were scantly reported. The one paper that focused on the ED and hospital involvement included the surgical capacity of staff, that being nurses (n = 12), surgeons (n = 9), and anesthesiologists (n = 5).Reference Solla, Carboni and Fernandez13 Supplies included the need for additional personal protective equipment, such as ballistic equipment and respiratory protection.Reference Arkins, Liao and O’Donnell7 The spaces used in responding to SMGEs were also scantly reported. The systems utilized to support a response were mostly related to disaster or mass casualty incidents (n = 3, 30%); however, this was variably reported. The reporting of patients transported to a hospital varied, as did the reporting of patient outcomes.
Lessons Learned
Lessons learned from each SMGE were mapped against the 4 surge capacity domains (see Table 4). Key lessons learned relating to staff included the need for greater interagency collaboration and clearer protocols to protect staff. Supplies required included additional burn equipment and generally a need for faster resupply of ambulances. To create safe spaces for EMS to operate, police were required to be involved.Reference Santos-Reyes and Olmos-Peña14 Most of the lessons related to the need to strengthen systems. This included the need to have in place a risk approach,Reference Santos-Reyes and Olmos-Peña14, Reference Dong, Liu and Liu15, Reference Tin, Cheng and Hata16 engage in interagency training and exercising,Reference Solla, Carboni and Fernandez13 and have patient flow processes well-established.Reference Krul, Sanou, Swart and Girbes17
Discussion
The health planning, operational response, and postevent stages of an SMGE should be conducted using a risk approach. This was highlighted in the lessons learned from the reported SMGEs in this review. An evaluation of the health risk at SMGEs should be undertaken similarly to that of other MGEs.Reference Bieh, Khan and El-Ganainy18, Reference Khan, Sabbagh and Ranse19 This risk assessment should consider the characteristics of the SMGE and the demographics of the participants.Reference Hutton, Ranse and Zimmerman20 Furthermore, it is well recognized that in addition to biomedicalReference Ranse and Hutton21, Reference Ranse, Hutton, Turris and Lund22 and environmental factors,Reference Hutton, Ranse and Gray23 psychosocial factors such as crowd mood and motivation are significant distinguishing factors in the number of patients presenting for injury and illness influencing health outcomes at MGEs.Reference Hutton, Ranse and Gray24 While the psychosocial factors of crowd mood and motivation are known to influence patient presentation rates and transport to hospital rates from MGEs, it could be surmised that these are more significant influencing factors in the SMGEs. This is the case as the crowd’s mood and motivation within the context of SMGEs can be volatile and unpredictable. Information about the volatility, mood, and motivation of the crowd at an SMGE may be haphazardly shared from organizers, attendees, responding agencies, and/or governments. As such, the availability and reliability of information from various agencies should be considered in an assessment of risk to ensure the safety and security of health staff to provide appropriate care.Reference Murnane, Simpson and Jongman25 Information about this volatility, mood, and motivation may be haphazardly shared, necessitating careful consideration of the reliability of information from various agencies to ensure the safety and security of health staff providing care.
An SMGE should be considered as a known hazard, and as such be embedded within disaster, and mass casualty incident plans for appropriate health service planning. Often mass casualty incident plans will have consideration of an all-hazards approach to planning and response, to do the greatest good for the greatest number of people.Reference Geale26, Reference Khorram-Manesh, Gray and Goniewicz27 However, when a particular hazard is known for a specific jurisdiction, it is reasonable to give additional weight to those hazards in mass casualty incident plans, using a top-hazards approach.Reference Bodas, Kirsch and Peleg28 For example, in jurisdictions with perennial events such as wildfires, floods, or cyclones, plans may include special considerations unique to responding to these events.Reference Skinner, Luther and Hertelendy29 Likewise, if a jurisdiction is known to have SMGEs, this should be considered a top hazard and have special consideration beyond an all-hazards approach. As identified in this review, such considerations should include staff requirements, safe spaces for staff to work, and additional supplies in general consumables and personal protective equipment.
This review highlighted the interagency approach to SMGEs. In particular, the relationship between police or security agencies and health agencies such as ambulances or EMS. Interagency approaches have been pivotal to the success of MGEs in general and SMGEs should be considered no different.Reference Bistaraki, McKeown and Kyratsis30 As such, an interagency approach, particularly between police and EMS, should be implemented at all stages of the planning and response for SMGEs. For preparations, an interagency approach may include the simulation or exercising of various SMGE scenarios. Using tools, such as CSCATTT (Command and Control, Safety, Communication, Assessment, Triage, Treatment, Transport) that have been used in the disaster context, may be useful in the SMGE context.Reference Sultan, Carlström and Sørensen31 If civil unrest tensions are rising in a jurisdiction, just-in-time exercising in the days leading up to a response may be of benefit. Simulation and exercising have been demonstrated to strengthen a response during mass casualty incidents, whereby agencies are known to one another, and role delineation is clear.Reference Timbie, Ringel and Fox32 During an SMGE interagency collaboration should be a balance of safety and security with health needs and outcomes. Interagency collaboration during the SMGE should provide safe passage for EMS and other health staff to provide care to patients. Potential challenges, such as conflicting priorities between security and health care, can be mitigated by establishing clear communication protocols and shared objectives. Additionally, ways to share intelligence regarding the SMGE should be encouraged.Reference Topol33
To help inform lessons learned from SMGEs there must be sharing of information. This review highlights a lack of volume in SMGE papers and a lack of consistency between these papers. Ensuring consistency in the collection, data reporting, and data dissemination of information will then inform future planning and response. The broader MGE literature has gained momentum to achieve consistency and quality in data reporting,Reference Ranse and Hutton21, Reference Ranse, Hutton, Turris and Lund22 and such an approach could be applied to the SMGE space. Based on the findings from this review, data that was collected on some occasions, and could be collected on all occasions, might include staff: skill mix, discipline, numbers; stuff: items used outside of general consumables and medical supplies; space: where was health care taking place; and systems: what was used to help support the health outcomes and staff protection, such as existing, revised or new processes. Furthermore, information about the SMGE itself would be useful, such as the estimated number of crowd attendees and the duration of the SMGE. Such quantity, quality, and consistency in data will help plan for future SMGEs.Reference Lund, Turris and Bowles34, Reference Turris, Lund and Hutton35 This approach would help inform a tailored, risk-based, and collaborative interagency approach, informed by robust data collection, for effectively managing the unique health challenges posed by SMGEs.
Study Limitations
A scoping review was a sensible place to start in developing a collective understanding of the peer-reviewed literature in the SMGE space. However, this approach has limitations primarily related to the lack of data-driven papers on this subject. As such, it was difficult to compare like-for-like SMGEs and subsequently health outcomes from these events. Likewise, there was a lack of some details, such as injury and/or illness to health care professionals at SMGEs. Future research should focus on more consistency and reporting of SMGEs to enhance our understanding of SMGEs and health resource requirements to enhance health outcomes. This review did not include gray literature and there may have been some instances where the gray literature provides some insights into health resourcing for SMGEs. Only papers written in English were included. Papers in other languages might provide different insights into SMGE health preparedness and response.
Conclusion
The increasing frequency and diverse nature of SMGEs present unique and significant challenges for health planning and response. Unlike their planned counterparts, SMGEs are characterized by their rapid onset, unpredictable nature, and often emotionally charged environments, making them inherently more complex to manage from a health perspective. To ensure appropriate and timely health service provision, a proactive and risk-based approach should be used in the health assessment and preparation for SMGEs with an emphasis on crowd mood and motivation. Mass casualty incident plans with an SMGE section should address staff requirements, provide safe working spaces for staff, and ensure additional supplies of general consumables and personal protective equipment. Key recommendations include embedding SMGE considerations within existing disaster and mass casualty incident plans, utilizing a top-hazards approach in jurisdictions prone to such events, and prioritizing robust interagency collaboration, particularly between law enforcement and health care agencies, across all stages of planning and response.
Supplementary material
The supplementary material for this article can be found at http://doi.org/10.1017/dmp.2025.10189.
Acknowledgments
The authors acknowledge the support of Anna Ormond, Reference Librarian, Wellington Medical and Health Sciences Library, University of Otago, New Zealand, for their contribution to the literature search.
Author contribution
The following author contribution statement is based on the Contributor Roles Taxonomy (CRediT) found at: https://www.elsevier.com/authors/journal-authors/policies-and-ethics/credit-author-statement
Conceptualization [JR, KG, AK-M], methodology [JR, KG, AK-M, LG, LM], investigation (screening) [JR, KG, AK-M, HDC, ASR, YR, LG, DT, FG, LM, NA, EC, FS, DB, KK, AH], formal analysis (data extraction) [JR, NS, KG, AK-M, HDC, ASR, YR, LG, DT, FG, LM, NA, EC, FS, DB, KK, AH], visualization [JR, NS, LG], writing the original draft [JR, NS], reviewing and editing drafts [all authors], and project administration [JR, AK-M]. All authors have approved the final submitted version of this paper.
Funding
This work was not funded by a research grant. Authors provided in-kind support through their personal time or the time afforded to them by their employee, who are listed as author affiliations.
Competing interests
The authors declare that they have no known competing financial interests that could have appeared to influence the work reported in this paper. Attila J. Hertelendy is a Deputy Editor of the journal Disaster Medicine and Public Health Preparedness. Jamie Ranse, Nebil Achour, Krzysztof Goniewicz, and Lesley Gray are Associate Editors of the journal Disaster Medicine and Public Health Preparedness. Amir Khorram-Manesh is a Guest Editor of the journal Disaster Medicine and Public Health Preparedness. The above-named Deputy Editor, Associate Editors, and Guest Editor have not had any role in the peer review of this paper. The review process has been conducted independently from these authors.
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