Public health emergencies can have devastating social, economic, and health consequences, including the loss of many lives in a short period of time. 1 A public health emergency can be defined as “an occurrence, or imminent threat of an illness or health condition that poses a substantial risk of a significant number of human fatalities, injuries or permanent or long term disability.” 2 Responding to a public health emergency requires strong, collective action at local, national, and international levels, including having a capable health system to prepare, plan, and manage these events. Reference Rose, Murthy and Brooks3
Strengthening public health emergency management has been a global priority for decades, notably since the early 2000s when severe acute respiratory syndrome coronavirus (SARS-CoV) spread across multiple countries, resulting in approximately 8000 cases and claiming more than 700 lives. Reference LeDuc and Barry4 In 2005, the International Health Regulations were revised with a focus on strengthening a country’s capacity to respond promptly and effectively to public health risks and public health emergencies. 5 One mechanism for complying with the International Health Regulations is by establishing and/or strengthening a country’s public health emergency operations center, or PHEOC. 2,5
A PHEOC is a physical or virtual space dedicated to coordinating the critical aspects of a public health emergency. 2 A PHEOC is typically activated in response to a public health emergency risk or event (both non-communicable and communicable diseases) and is integral to providing a coordinated response, particularly when routine public health services, systems, and structures are overwhelmed. 2,Reference Bryant, Sosin and Wiedrich6 Within a PHEOC, an incident management system is commonly used, which typically consists of 5 core functions: command, operations, logistics, planning, and administration/finance. These functions work together to implement tasks such as data collection and dissemination, deployment of resources (staff, equipment, and supplies), organizing/allocating funding, and communicating with other agencies and to the public. 2,7
Stemming from the challenge of fighting wildfires in the United States, Reference Stambler and Barbara8 the incident management system was established in the 1960s and 1970s to enable better coordination of emergencies across different agencies and geographic borders. Reference Rose, Murthy and Brooks3 The incorporation of the incident management system into public health emergency management emerged in the early 2000s. Reference Rose, Murthy and Brooks3 The United States Centers for Disease Control and Prevention (CDC) was one of the early adopters of the incident management system, establishing an Emergency Operations Center (EOC) within the Division of Emergency Operations in 2003. Shortly after this EOC was established, it responded to SARS-CoV and the Indonesia Tsunami. Reference Redd and Frieden9–Reference Papagiotas, Frank and Bruce11
In 2014, the Global Health Security Agenda (GHSA) was founded to help strengthen country capacity to prevent, detect, and respond to infectious disease risk. One of the key GHSA 5-year targets was for every country to have a functioning PHEOC. 12 In the same year, the evolving Ebola virus disease (EVD) crisis in West Africa saw the establishment of PHEOCs in several African countries to respond to this public health emergency. Reference Marston, Dokubo and van Steelandt13 In 2015, the World Health Organization’s (WHO) Emergency Operations Centre Network (EOC-NET) produced specific guidance to support and strengthen countries in using PHEOCs for public health emergencies through the development of the WHO Framework for a Public Health Emergency Operations Center. 2
Given the growing support for using a PHEOC in public health emergency management, it is pertinent to understand the role of PHEOCs in recent public health emergencies. This scoping review therefore documents the role of PHEOCs in managing public health emergencies since the West African Ebola virus disease outbreak (2013–2016) and describes the factors that have influenced the effective use of a PHEOC in public health emergency management.
Methods
Scoping review steps outlined by Arksey and O’Malley (2005) and based on the PRISMA-ScR Checklist are described below. Reference Arksey and O’Malley14,Reference Tricco, Lillie and Zarin15
Research Questions
Two key research questions were explored in this review:
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1. What role has a PHEOC played in managing public health emergencies/risks?
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2. What factors (barriers/enablers) have influenced the effective use of a PHEOC when responding to public health emergencies/risks?
Identification of Relevant Literature
Peer-reviewed databases and selected grey literature websites were searched between November and December 2020. With the assistance of a research librarian, an exploratory search was first carried out in Medline (OVID) for key MeSH terms. A comprehensive search was then conducted in PubMed, Scopus, Web of Science, Cochrane – Systematic Reviews (including special COVID collections) and Google Scholar. Search terms varied depending on the database (Table 1). Selected websites were also searched, including key global health organizations, national government health authorities, and non-government global health websites. For the list of grey literature websites, see Data Supplement 1.
Selection of Studies According to the Pre-Established Criteria
Inclusion criteria
The studies included in this review were published between January 2016 and October 31, 2020. This date range was chosen to reflect a critical time for strengthening the use of PHEOCs, as a result of lessons learned from the West African EVD (2013–2016) Reference Coltart, Lindsey and Ghinai16 and the publication of the WHO Framework for a Public Health Emergency Operations Center (2015). 2
The studies described research or practice specific to the role of PHEOC in a public health emergency and/or the factors influencing the effective use of a national PHEOC or EOC (these terms are used interchangeably in the literature).The definition of a public health emergency was drawn from the WHO Framework for a Public Health Emergency Operations Center: “An occurrence, or imminent threat, of an illness or health condition that poses a substantial risk of a significant number of human fatalities, injuries or permanent or long term disability.” 2 Due to the language of the reviewers, only English language publications were reviewed.
Data extraction and analysis
A title and abstract review occurred within each peer-reviewed database and grey literature source. Full text screening was performed in EndNoteX9. Information was extracted from each paper into Microsoft Excel. Results were discussed between 2 authors and a member of the WHO, EOC-NET secretariat who provided advice and guidance throughout the data extraction and analysis process. Any disagreements were resolved by consensus discussion. Extracted data included:
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Study characteristics (eg, country of origin)
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Public health emergency
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Role of PHEOC in a public health emergency
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Factors (barriers/enablers) influencing use of a PHEOC
For a summary of data extracted for review, see Data Supplement 2.
Results
A total of 42 articles (28 peer reviewed and 14 grey literature publications) matched the inclusion criteria (Figure 1).
Study Characteristics
Twenty-two national PHEOCs were identified in this review. PHEOCs were located in countries across all 6 WHO regions: Africa (n = 9); Eastern Mediterranean (n = 2); Americas (n = 2); South-East Asia (n = 2); Europe (n = 2); and Western Pacific (n = 5).
PHEOCs were used to respond to a range of public health emergencies, including coronavirus disease (COVID-19) (n = 11), EVD (n = 6), polio, cholera, Middle East respiratory syndrome coronavirus (MERS-CoV), dengue fever, enterovirus, novel influenza A virus infections (H1N1, H7N9), rabies, Zika virus, Lassa fever, monkey pox, Chikungunya virus, plague, floods, hurricanes, mass gatherings, and a train derailment. Table 2 summarizes the national PHEOCs included in this review and the public health emergencies they have responded to.
Review Question 1: What Role Has a PHEOC Played in Managing Public Health Emergencies/Risk?
The literature indicated that PHEOCs played a role in both the preparedness and response phase of public health emergencies featured in this review. Eight studies mentioned the role of a PHEOC in the preparedness phase. Reference Aceng, Ario and Muruta17,Reference Bousso19–Reference Standley, MacDonald and Attal-Juncqua22,Reference Brooks, Pinto and Gill26,Reference Ding, Li and Jin43,Reference Elachola, Al-Tawfiq and Turkestani52 In the preparedness phase, PHEOCs were used to support tasks such as risk mapping, Reference Bousso19 training and exercises, Reference Aceng, Ario and Muruta17,Reference Bousso19,Reference Balajee, Pasi and Etoundi21,Reference Standley, MacDonald and Attal-Juncqua22 detection of emerging issues/surveillance, Reference Brooks, Pinto and Gill26,Reference Ding, Li and Jin43,Reference Elachola, Al-Tawfiq and Turkestani52 and drafting of plans. 20 Twelve studies described the role of a PHEOC in the response phase, including assisting with mobilizing financial and human resources, Reference Aceng, Ario and Muruta17,Reference Yao25,Reference Brooks, Pinto and Gill26,Reference Alabbadi and Al-Masaeed30 providing and monitoring technical and strategic coordination, Reference Mobula, Samaha and Yao18,Reference Vaz, Mkanda and Banda23,Reference Yao25,Reference Alabbadi and Al-Masaeed30 situational awareness, Reference Mobula, Samaha and Yao18,Reference Vaz, Mkanda and Banda23 advice and support, Reference Huang44,Reference Kim, Oh and Wang47 guiding field activities, Reference Aceng, Ario and Muruta17 tracking, collecting, and analyzing data, Reference Balajee, Pasi and Etoundi21,Reference Alabbadi and Al-Masaeed30,Reference Ding, Li and Jin43 information sharing amongst partners and the public, Reference Balajee, Pasi and Etoundi21,Reference Alabbadi and Al-Masaeed30,Reference Elachola, Al-Tawfiq and Turkestani52,53 and implementing response/operational plans. 20,Reference Balajee, Pasi and Etoundi21
Review Question 2: What Factors (Barriers and Enablers) Influenced the Effective Use of a PHEOC When Responding to a Public Health Emergency/Risk?
This section outlines the factors (barriers and enablers) found to influence the effective use of a PHEOC when responding to a public health emergency.
Factor 1: Incident management system and coordination
Barriers
Using an incident management system (IMS) posed challenges when running a PHEOC. Two studies noted a lack of understanding of the incident management system structure and its related functions. Reference Su, Wu and Lee45,Reference Otu, Ameh and Osifo-Dawodu54 For example, Kim et al. Reference Kim, Oh and Wang47 found that during a MERS-CoV outbreak in South Korea, there were “varying levels of understanding of an Incident Control System” that made it difficult for the ICS to function as expected. Reference Kim, Oh and Wang47 Brooks et al. Reference Brooks, Pinto and Gill26 also noted that several countries experienced challenges related to implementing the IMS when responding to EVD in West Africa in 2014. For example, the EOC in Guinea cited a lack of standardized definitions within the IMS, which led to different interpretations of indicators and roles. Reference Brooks, Pinto and Gill26
The agency in charge of coordinating the IMS was also cited as a factor impacting the running of a PHEOC. For example, during the Sierra Leone EVD outbreak (2013–2016), there were different institutions coordinating the IMS throughout the response. This often led to tensions between local agencies and with agencies from abroad. Reference Ross29 Two studies also described the challenge of the IMS coordinator/commander having insufficient mandate to hold others to account or to make decisions without being challenged by other authorities, which made it difficult to progress decisions. Reference Ross29,Reference Otu, Ameh and Osifo-Dawodu54
Enablers
Seven studies identified the importance of using an incident management system to enable clear coordination and to optimize the efficiency of a PHEOC. Reference Bousso19,Reference Olu, Lamunu and Chimbaru28,Reference Ross29,Reference Hinjoy, Tsukayama and Chuxnum40,Reference Delaney41,Reference Su, Wu and Lee45,Reference Kim, Oh and Wang47 An incident management system was found to assist with prompt decision making, helped reduce duplication, and encouraged the development of plans to clarify PHEOC functions, roles, and responsibilities. Reference Mobula, Samaha and Yao18,Reference Brooks, Pinto and Gill26,Reference Olu, Lamunu and Chimbaru28,Reference Alabbadi and Al-Masaeed30,Reference Su, Wu and Lee45,Reference Kim, Oh and Wang47 Having 1 unified command with support functions also helped integrate the incident management system with the public health functions. Reference Kim, Oh and Wang47
Factor 2: Plans, policies/procedures, and legal authority
Barriers
Three studies cited having an inadequate planning framework to assist with preparing and responding to a public health emergency. Reference Ross29,Reference Alabbadi and Al-Masaeed30,Reference Otu, Ameh and Osifo-Dawodu54 In addition, when responding to an EVD outbreak, the Nigerian national PHEOC did not have any formal agreements within the teams working in the IMS, which led to problems of ownership, accountability, and challenges with setting working limits. Reference Otu, Ameh and Osifo-Dawodu54
Enablers
Several studies noted the importance of having clear public health emergency plans, policies and procedures, and a legal mandate to operate the PHEOC to enable the smooth running of a PHEOC. Reference Bousso19,Reference Balajee, Pasi and Etoundi21,Reference Brooks, Pinto and Gill26,Reference Kim, Oh and Wang47 This included a plan with clearly articulated criteria for activating a PHEOC and tailoring the plan to a country’s existing legislative framework. Having a legally binding plan was also suggested to create a strong foundation for seeking additional funds, resources, and support in the event of a public health emergency. Reference Bousso19,Reference Balajee, Pasi and Etoundi21,Reference Brooks, Pinto and Gill26,Reference Kim, Oh and Wang47 Long-term planning of human, technical, and financial resources and planning for how the PHEOC would be used during “peace time” was also important, particularly in consideration of sustaining the PHEOC beyond a public health emergency response. Reference Aceng, Ario and Muruta17,53
Factor 3: PHEOC partnerships, communication
Barriers
Communication within and external to the PHEOC was noted by several studies as having an impact on the effective running of a PHEOC. Reference Standley, MacDonald and Attal-Juncqua22,Reference Olu, Lamunu and Chimbaru28,Reference Yang, Noh and Song49,Reference Yang, Chen and Su55 For example, during the MERS-CoV outbreak in South Korea (2015), there was no crisis information sharing system, which resulted in a lack of communication between the different levels of government and across agencies. Olu et al. Reference Olu, Lamunu and Chimbaru28 also cited a lack of data sharing across stakeholders and within internal government departments, making it hard to ascertain situational awareness and implement an appropriate response. Reference Olu, Lamunu and Chimbaru28 Information sharing between the PHEOC and the public was also problematic during the MERS-CoV outbreak in South Korea, with inconsistent messaging and communication lacking transparency, resulting in community mistrust. Reference Yang, Noh and Song49
Enablers
“At nearly every level, personalities and personal relationships appeared to be key to the functioning of the PHEOC.” Reference Standley, MacDonald and Attal-Juncqua22 Five studies discussed the importance of clear communication between the PHEOC and external agencies, including the sharing of tools, resources, and information amongst partners to enable buy-in, mutual ownership, political leverage, and seamless collaboration. Reference Mobula, Samaha and Yao18,Reference Balajee, Pasi and Etoundi21–Reference Vaz, Mkanda and Banda23,Reference Olu, Lamunu and Chimbaru28 Having an official spokesperson to engage and share information with regional and international organizations was important to enhance interagency communication. Reference Hinjoy, Tsukayama and Chuxnum40 Regular meetings with partners, including developing a “cooperative agreement” to support innovative and collaborative response activities, were cited as an important aspect of enhancing communication and cooperation. Reference Standley, MacDonald and Attal-Juncqua22 Three studies noted the importance of strong internal communication and cooperation within a PHEOC to enable strategic decision-making, to support efficient mobilization of resources, and to ensure timely dissemination of risk communication messages. Reference Standley, MacDonald and Attal-Juncqua22,Reference Ross29,Reference Kim, Oh and Wang47 Kim et al. Reference Kim, Oh and Wang47 also noted that having 1 person in charge enabled a clear communication mechanism to reduce conflict over critical issues, such as when to release risk communication messages to an affected community. Reference Kim, Oh and Wang47
Factor 4: Information/data management
Barriers
Many studies found managing data and information within a PHEOC to be a challenge. 20,Reference Hinjoy, Tsukayama and Chuxnum40,Reference Huang44,Reference Su, Wu and Lee45 The “fragmented” nature of data streams, including surveillance data collected through multiple sources, made it hard for the timely detection of outbreaks and for accurate situational analysis. Reference Balajee, Pasi and Etoundi21 Several studies highlighted issues relating to accessing up-to-date, comprehensive information detailing the availability and tracking of resources and assets. Reference Olu, Lamunu and Chimbaru28–Reference Alabbadi and Al-Masaeed30 Another key barrier to data coordination was having different data collection guidelines and reporting formats across different agencies, making it hard for the PHEOC to collate this information in a timely manner. Reference Olu, Lamunu and Chimbaru28,Reference Ross29
Enablers
Having access to appropriate technology within a PHEOC was found to enhance the timely detection, collection, and interpretation of data essential to an efficient public health emergency response. Reference Mobula, Samaha and Yao18,Reference Vaz, Mkanda and Banda23 “Investing early” in the most appropriate technology to collect and manage information, including a database with information on previous public health emergencies and lessons learnt, was suggested as an important part of preparing for a public health emergency. Reference Nyenswah, Kateh and Bawo27,Reference Alabbadi and Al-Masaeed30 One study noted the importance of having a national inventory system to ensure the prompt mobilization and deployment of resources in the event of a public health emergency. Reference Olu, Lamunu and Chimbaru28 Another study suggested consideration of innovations such as artificial-intelligence-based information and communication technology to explore the potential to enhance surveillance and outbreak forecasting. “Successful innovation along with local adaptations and experience have to be quickly and widely shared with global society to overcome common challenges.” Reference Yang, Noh and Song49
Factor 5: Workforce capacity and training
Barriers
Many PHEOCs, particularly in low resource settings, found building and sustaining a PHEOC workforce to be a challenge. The constant turnover of staff and the continuity of operations for staff who moved from other departments often led to gaps in the implementation of tasks within the PHEOC and in other public health programs. Having a small workforce made it harder to upscale in the event of a public health emergency. Reference Balajee, Pasi and Etoundi21,Reference Brooks, Pinto and Gill26,Reference Olu, Lamunu and Chimbaru28,Reference Okeibunor, Nsubuga and Salla56
Enablers
Conversely, building and sustaining a competent workforce through recruitment, training, and retention of qualified and skilled staff enabled the successful running of a PHEOC. Six studies mentioned the importance of training PHEOC staff in the “practical elements of working in a PHEOC,” including the principles of incident management system, writing action plans, conflict resolution, communication, and logistics management. Along with these, upskilling staff in the technical aspects of a public health emergency such as epidemiology, including analyzing, interpreting, and presenting data, was also important. Reference Bousso19,20,Reference Olu, Lamunu and Chimbaru28,Reference Ding, Li and Jin43,Reference Su, Wu and Lee45,53 One study suggested on-the-job training for coordination leaders to ensure a “better understanding of the coordination mechanism and enhance their coordination capacity” during a public health emergency. Reference Olu, Lamunu and Chimbaru28 Previous experience working in public health emergency response was suggested to enhance efficiency in responding to new public health emergencies. 39
Factor 6: Physical infrastructure, location, and resources
Barriers
Several barriers related to the physical layout and the infrastructure within a PHEOC were found to hinder effective PHEOC operations. These barriers included the PHEOC having inadequate or inappropriate office space, lack of access to the Internet, and lack of access to proper communication equipment. Reference Brooks, Pinto and Gill26,Reference Olu, Lamunu and Chimbaru28
Enablers
Conversely, the location and design of the PHEOC were found to help promote smooth PHEOC operations. Locating the PHEOC close to or within the ministry of health was deemed important for ease of operations, particularly for staff working dual roles. Using an “open plan” and ensuring space for multidisciplinary teams to meet and share information were found to enhance communication and coordination. In addition, ideally, locating the PHEOC away from potential hazards and having power backup (eg, generator) and paper copies of key documents were suggested to assist continuity of operations in the event of a natural disaster or power failure. Reference Elachola, Al-Tawfiq and Turkestani52 Ultimately, having a permanent PHEOC that can be used during outbreak and non-outbreak periods for routine duties, such as surveillance, was suggested to help sustain resources, infrastructure, and the workforce required to analyze and interpret incoming health information and to assist with a quick transition to response mode in the event of a public health emergency. Reference Ding, Li and Jin43
Discussion
This review highlighted the role of national PHEOCs in responding to recent public health emergencies and identified the barriers and enablers influencing the effective running of a PHEOC in a public health emergency. Some of the barriers experienced by countries using a PHEOC in public health emergency management included having poor information and data management systems, a lack of infrastructure, and workforce capacity issues. These challenges are congruent with existing public health and broader health care issues experienced by countries, particularly in low-resource settings. Reference Brencic, Pinto and Gill10,Reference Rennie and Hunter57–Reference Ma, Huang and Zheng59
Understanding the incident management system, including the different incident management functions, was also a barrier identified in this review. Reference Ross29,Reference Su, Wu and Lee45,Reference Kim, Oh and Wang47 Strengthening incident management system training in the preparedness phase of public health emergency management, as well as conducting on-the-job training during a public health emergency could assist in addressing this issue. Reference Olu, Lamunu and Chimbaru28 Since the formation of the Global Health Security Agenda, the CDC has prioritized support for countries in emergency management training, Reference Redd and Frieden9 including the implementation of a public health emergency management fellowship program. 60 The WHO has also developed a range of online training courses through the OpenWHO knowledge transfer platform, including the Incident Management System (Tier 1 and Tier 2), Standard Operating Procedures for Emergencies, and Ready 4 Response Training. 61 The WHO has also produced specific guidance on training and exercises through the Handbook for Developing a Public Health Emergency Operations Centre Part C: Training and Exercises. 62 Assessing training needs and utilizing the existing training platforms, such as those mentioned above, could help strengthen this area. Beyond this review, it would also be valuable to investigate factors that influence the use and potential adaptation of the traditional incident management functions in a PHEOC to optimize the effectiveness of using an IMS when responding to public health emergencies.
Enablers to support the effective use of a PHEOC in public health emergency management included adopting an incident management system, having strong government support and legal authority to establish a PHEOC, skilled and trained staff, and efficient information management systems. These enablers align with current best practice in establishing and operating an PHEOC. 2,63 For example, the WHO Framework for a PHEOC recommends that governments, ministries, or departments establish, support, or advise PHEOCs at all levels (local, provincial/state, and national) to ensure that the PHEOC 2 :
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Uses an incident management system
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Has sufficient skilled staff who are trained in the IMS
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Has strong government support
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Has legal authority
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Has effective information management systems
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Is sufficiently funded
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Has sufficient infrastructure 2
Importantly, having clear legal authority to establish and operate a PHEOC and embedding these legalities into PHEOC plans can provide a strong foundation for activating and gaining support for using a PHEOC. 2 Bousso Reference Bousso19 also suggests engaging authorities in dialogue to explain the purpose of a PHEOC when initially establishing a PHEOC, as an important early step in gaining support, and prioritizing funding and resources for establishing a permanent PHEOC. Reference Bousso19 Guidance on how to establish a PHEOC legal framework has recently been developed by the WHO regional office of Africa, to strengthen advocacy and capacity in this area. 64 These suggestions can be applied to PHEOCs at local, state/provincial, and national levels.
Although this review identified the barriers and enablers that influenced the use of a PHEOC, none of the included studies measured the impact these factors have had on public health emergency outcomes. Ma et al. Reference Ma, Huang and Zheng59 highlights a dearth of evidence from countries in evaluating the effectiveness of using a PHEOC in public health emergency preparedness and response. Reference Ma, Huang and Zheng59 Demonstrating the effectiveness of using a PHEOC in public health emergency management is important in validating current “best practice” guidance, as well as in advocating for the use of a PHEOC at national, state/provincial, and local levels. Countries could consider incorporating performance metrics to track implementation and assess effectiveness of interventions. For example, Mobula et al. Reference Mobula, Samaha and Yao18 suggest having “a comprehensive monitoring framework that looks at inputs, outputs, outcomes, and impacts, with key performance indicators to guide the implementation of multi-sectorial operations in real time.” Reference Mobula, Samaha and Yao18 Developing and applying outcomes-based indicators focused on critical timing and actions and measuring how these impact a public health emergency response could be an important consideration for countries in demonstrating the effectiveness of a PHEOC.
Limitations
While this review was comprehensive, we acknowledge that some publications may have inevitably been missed, including those published in languages other than English. Our interpretation of the WHO public health emergency definition may also have meant that we did not capture the plethora of non-communicable disease events that a PHEOC may have responded to. We also acknowledge we may not have captured every national PHEOC that exists.
As one author extracted primary data from the peer-reviewed articles, this may have also introduced some bias. To reduce this bias, during the peer-review extraction and analysis phase, the author consulted with the second author and a broader advisory team consisting of the WHO secretariat on the selected articles, and discussed any ambiguous cases.
Conclusions
Using a PHEOC to respond to public health emergencies has become more common in the past 2 decades. The featured studies have highlighted the public health emergencies that PHEOCs have responded to and the barriers and enablers found to influence the effective use of a PHEOC during these events. Many of the factors found to support the effective use of a PHEOC are congruent with current best practice guidelines. While organizations such as the World Health Organization and the United States Center for Disease Control and Prevention provide support and guidance to countries in establishing and strengthening the PHEOCs, many challenges remain. Further research is required to address the barriers identified in this review to optimize the use of a PHEOC in public health emergency management in the future. In addition, evaluating the effectiveness of using a PHEOC in public health emergency management will not only assist with helping validate the “best practice” guidance that currently exists, but also will be a powerful advocacy tool for strengthening the evidence for using a PHEOC in public health emergency management in the future.
Supplementary material
To view supplementary material for this article, please visit https://doi.org/10.1017/dmp.2023.50
Data availability statement
All data collected and analyzed for this scoping review are included in this manuscript.
Acknowledgments
This study was commissioned and paid for by the World Health Organization (WHO). Copyright in the original work on which this article is based belongs to WHO. The authors have been given permission to publish this article. The authors alone are responsible for the views expressed in this publication and they do not necessarily represent the views, decisions or policies of WHO. The authors would like to thank the WHO Public Health Emergency Operations Centre Network (EOC-NET) Secretariat for guidance including advice on the review protocol and communicating the research findings.
Author contributions
Tammy Allen prepared the draft review protocol; led the peer-reviewed literature identification, data extraction, and analysis; led the grey literature analysis; consulted with the WHO EOC-NET Secretariat for guidance and support, and wrote the manuscript. Rosalie Spencer assisted with the development of the draft protocol, led the grey literature identification and data extraction, and contributed to the manuscript text.
Conflict(s) of interest
None.