Temporal Distribution Analysis
Figure 2 showed us the first international article on PHEM was published in 1991. The number of articles fluctuated slowly in the next few years. After 2001, it began to increase rapidly. It was worth noting that the number of articles in 2014 is high, reaching 206. It declined in the next two years. Until 2017, the number of articles reached its peak, 219. The study on PHEM in China started in 2003 and declined slowly until 2005. During 2006–2013, there was a rapid development; many articles appeared in this period. The minimum number in 2006 also reached 41, the maximum was in 2013, reaching an astonishing 96. Thus, the average number also peaked at 70.0. The number of articles declined after 2013, reaching 49 in 2018. In contrast, the study in China started late than in some countries, yet a large number of Chinese scholars participated in this study at the beginning.
After the descriptive analysis of the data, we conducted a polynomial prediction analysis of the number of articles and predicted it in the next three years. The trend of chronological distribution of articles related to PHEM in international data can be expressed as follows: y = 0.2790x2+0.7688x-7.7708 (R2 = 0.9577), while Chinese data was: y= -0.0345x3+1.5079x2-14.142x+27.273 (R2 = 0.9251). Y indicated the number of articles and x indicated the years. R2 > 0.9, indicating a good degree of fit. The chronological distribution of international articles showed a trend of the increasing year by year. In 2019–2021, the annual number of articles will exceed that of previous years. At the same time, the trend line of Chinese articles like a wave line, and the number of articles will continue to decrease to the next three years. Besides, as time goes on, the gap in the number of articles in Chinese and international will be gradually increasing.
Cooperation Network Analysis
Co-Author
Figure 3, the international co-author network, showed that there were many authors studied on PHEM, and some had collaborated. The top-ranked item by citation counts was Daniel J. Barnett (DANIEL J BARNETT in the figure) with a citation count of 20 (all the count did not show in the figure). Then was Elena Savoia (ELENA SAVOIA) and Lainie Rutkow (LAINIE RUTKOW); all their citation counts were 17. These were authors who paid great attention to this field and had published more articles. Most of these authors were from American universities, such as Johns Hopkins University, Harvard University. The top-ranked items by centrality were Frederick M. Brokle (FREDERICK M), Task Force for Pediatric Emergency Mass Critical Care (TASK FORCE PEDIAT EMERGENCY MASS C CA) and James G. Hodge (JAMES G), with the centrality of 0.06 (all the centrality did not show in the figure). However, all three items' centrality was less than 0.1. Figure 4, the top-ranked item for Chinese scholars by citation counts was Qunhong Wu with citation counts of 22. Then was Yanhua Hao (17), Feng Han (11), Ning Ning (10), Yadong Wang (10), Zheng Kang (8), Ying Liu (6), Jincheng Ma (6), Mingli Jiao (5), Libo Liang (5). Most of them were teachers at Harbin Medical University. The top-ranked items by centrality were Yanhua Hao, and Ning Ning, with the centrality of 0.02. The third one was Qunhong Wu, with the centrality of 0.01. Their nodes’ centrality also less than 0.1. In terms of the quantity and quality of articles, Qunhong Wu and Yanhua Hao were the leaders of PHEM in China. From the co-author network, we can see that many authors in internationally and China are collaborating on PHEM. (Additional file 1: Table S1, Table S2, and Figure S1).
Co-Institution
Just like a co-author, many institutions had studied on PHEM (figure 5 and figure 6). The top-ranked item by international citation counts was the Centers for Disease Control and Prevention (Ctr Dis Control & Prevent.), with citation counts of 255, which means that the institution publishes the largest number of articles in this field. The second one was Johns Hopkins University (Johns Hopkins Univ.), with citation counts of 92, and it meant that Johns Hopkins University had the largest number of articles published among the universities in this field. Then was Harvard University (Harvard Univ.), Columbia University (Columbia Univ.), and so on. The above analysis showed that CDC and universities were the leading institutions to study on international PHEM. The centrality ranked item was CDC (0.50). Then was Johns Hopkins University (0.21), Harvard University (0.16), University of Washington (Univ Washington., 0.13), University of Toronto (Univ Toronto., 0.10), University of Pittsburgh (Univ Pittsburgh, 0.10) and Boston University (Boston Univ., 0.10). All these nodes’ centrality was no less than 0.1 with the purple circle, which meant that they were the institutions with higher publication quality and the leading institutions in this field. The top-ranked item by citation counts of the Chinese database was the School of Health Management, Harbin Medical University, with citation counts of 20. Then was Shanghai Publishing and Printing College (9), National Health and Family Planning Commission of the People’s Republic of China (7), School of Health Administration and Education, Capital Medical University (6), and so on. The top-ranked item by centrality was the School of Health Management, Harbin Medical University, with a centrality of 0.04. The second one was the China National Health Development Research Center, with the centrality of 0.03. Then, we can see the School of Health Management, Harbin Medical University is a leader in the field of research in China. In comparison, CDC had the largest publication volume and influence in the international, while universities dominated the field of research instead of health institutions in China. (Additional file 1: Table S3, Table S4, and Figure S2).
Co-Country
Table 1 summarized the top 10 countries in the count and centrality of international PHEM research. We can see that the development of PHEM researches differs from countries, and it mainly centralized in the USA, Canada, England, Australia, P. R. China, Switzerland, Italy, Sweden, Japan, Netherlands. According to the income levels from the World Bank [42], these countries were all high-income countries except China. Geographically, half of them centralized in Europe. Among these countries, the USA was the most productive country, far ahead of the rest in this field, and its centrality was the largest. This showed that in the field of PHEM, the USA carries out the most study, and their study was more advanced. Although China ranks fifth in the number, its centrality was only 0.03. Therefore, these results indicated that Chinese scholars could publish some internationally recognized articles in the field, which had an advantage in quantity; but, they need to improve the articles’ quality. It was worth noting that although the number of Switzerland (44) and Sweden (34) articles was much lower than that of the USA, the articles’ centrality of these two countries was more than 0.10, which showed that the quality of the articles was still high.
Table 1 Top 10 countries in the count and centrality of international database
|
Count
|
Country
|
Centrality
|
Country
|
1557
|
USA
|
0.67
|
USA
|
138
|
Canada
|
0.32
|
England
|
131
|
England
|
0.16
|
Switzerland
|
114
|
Australia
|
0.16
|
Sweden
|
95
|
P. R. China
|
0.11
|
Canada
|
44
|
Switzerland
|
0.08
|
Germany
|
34
|
Italy
|
0.06
|
Australia
|
34
|
Sweden
|
0.06
|
India
|
30
|
Japan
|
0.04
|
Netherlands
|
27
|
Netherlands
|
0.03
|
P. R. China
|
Abbreviation: P. R. China = People’s Republic of China
Co-word Network Analysis
Keywords Co-occurrence Network Analysis
Generally speaking, keywords represent the research hotspots, which means topics of wide concern for researchers in this field. From figure 7 we can saw, top 10 keywords ranked by citation counts for the international database was public health (297), preparedness (215), emergency preparedness (191), disaster (187), health (142), emergency (133), care (128), United States (121), bioterrorism (102), and impact (96). The top ten centrality was emergency department (0.22), prevalence (0.18), surveillance (0.17), knowledge (0.15), public health preparedness (0.15), children (0.14), management (0.14), trauma (0.13), simulation (0.13), policy (0.11). All their centrality was more than 0.10, which meant they had more influence than other keywords. Figure 8 showed top 10 keywords of Chinese PHEM research was public health emergencies (394), emergency management (154), health emergency (116), public health (101), emergencies (84), emergency response ability (78), public health events (58), emergency mechanism (33), emergency disposal (28), public emergencies (27). Nodes whose centrality over 0.1 was health emergency (0.45), public health (0.32), public health emergencies (0.30), emergency management (0.26), emergencies (0.23), public health events (0.13), and emergency response ability (0.12). Comparing the distribution of keywords in the international and Chinese, we can see that the international study mainly focuses on the emergency preparedness and monitoring for public health events, while the Chinese research mainly focuses on the analysis and disposal for it. (Additional file 1: Table S5, Table S6, and Figure S3).
Burst Detection Analysis
Figure 9 and figure 10 illustrated the keywords with the strongest citation burst for international and Chinese databases. The international keywords detected 52 burst words, while the Chinese data detected 18 burst words. Research frontier of international PHEM included anthrax, public health, weapon, bioterrorism, accident, trauma, terrorism, emergency response, and so on. Among these words, bioterrorism (28.7902) was the strongest burst keyword, which was during the period between 2002 and 2009. Then was Ebola (15.6855, 2015–2018), disaster planning (10.2745, 2014–2016), terrorism (9.9846, 2004–2008). All these showed us a greater attention to this study topic and better exemplify the study front in this period. From the perspective of the time development sequence, international research on PHEM begins with terrorism and bioterrorism. After that, disaster planning and emergency preparedness have become a new research frontier (2004–2014). In recent years (2015–2018), epidemics and infectious diseases have become the focus of study. Research frontier of Chinese PHEM included public health emergencies, United States of America, North America, emergency disposal, united states, sudden events, public health, emergency, emergency response, public emergencies, disease prevention and control agency, evaluate, emergency drill, risk assessment, assessment, health emergency management, health emergency response ability, Delphi method. During 2003–2008, Chinese research on PHEM was in its infancy. The main research frontiers were public health emergencies and America. It was mainly at the stage of the formation of the Chinese theory of this field. By learning from the experience of the United States in dealing with health emergencies, scholars began the study of PHEM in China. Then, Chinese scholars began to study the links involved in the disposal of public health emergencies, such as response, organization, evaluation, exercise, and evaluation of PHEM. After 2016, health emergency management, health emergency response ability, and the Delphi method had become the new research front. In contrast with international and Chinese research on PHEM, it can be found that international research often relates to hot issues, while China focuses on the management procedure (Additional file 1: Figure S4).
In order to further explain the above research hotspots, the top 8 cited articles were shown in table 2 and table 3. The top 8 ranked articles by citation for international database appeared in the year of 2005, 2007, 2009, 2014, 2015, 2016. The article Elevated blood lead levels in children associated with the flint drinking water crisis: a spatial analysis of risk and public health response was the most cited (372) international article [43]. Then was The 2006 California Heat Wave: Impacts on Hospitalizations and Emergency department visits [44]. In terms of the time distribution, the research on international bioterrorism started first [45], then was recommendations for health emergency response teams and health incident management [46, 47]. In recent years, the causes and disposal of public health events were the hotspots of international attention [43, 48–]. This was basically consistent with the analysis results of the above research keywords. Chinese top 8 cited articles of PHEM, appeared in the year of 2003, 2004, 2009, 2011. Table 3 showed us that the most frequently cited Chinese article was Emergency logistics [51] written by Zhongwen Ou, Huiyun Wang, Dali Jiang et al. frequency reached an astonishing number, 473. Secondly, Kaibin Zhong’s article Review and prospect: construction of emergency management system in China [52]. The three articles: Legislative situation and characteristics of China’s emergency law [53], Legal construction of public emergency response in China: legal construction task proposed by SARS crisis management practice [54], The realistic subject of administrative rule of law in public emergency management [55] mainly researched the legal construction of PHEM in China. They all published in 2003, proving that China mainly carried out the research on the legal construction of PHEM during that time. In other words, PHEM in China starts with legal system construction. In 2004, Chinese scholars began to establish a knowledge domain for health emergency response and disposal. With the extensive research, Chinese scholars began to research on international PHEM in 2011.
Table 2 Top 8 cited articles of international database
|
Count
|
Author
|
Title
|
Journal
|
Year
|
372
|
Mona Hanna-Attisha, Jenny LaChance, Richard Casey Sadler, et al.
|
Elevated blood lead levels in children associated
with the flint drinking water crisis: a spatial analysis of risk and public health response
|
American Journal of Public Health
|
2016
|
366
|
Kim Knowlton, Miriam Rotkin-Ellman, Galatea King, et al.
|
The 2006 California Heat Wave: Impacts on Hospitalizations and Emergency department visits
|
Environmental Health Perspectives
|
2009
|
365
|
Karin Stettler, Martina Beltramello, Diego A. Espinosa, et al.
|
Specificity, cross-reactivity, and function of antibodies elicited by Zika virus infection
|
Science
|
2016
|
316
|
Nathalie Embriaco
, Elie Azoulay, Karine Barrau, et al.
|
High level of burnout in intensivists - Prevalence and associated factors
|
American Journal of Respiratory and Critical Care Medicine
|
2007
|
305
|
Salim S. Abdool Karim, Gavin J. Churchyard, Quarraisha Abdool Karim, et al.
|
Health in South Africa 3 HIV infection and tuberculosis in South Africa: an urgent need to escalate the public health
response
|
Lancet
|
2009
|
286
|
Daniel P. Aldrich, Michelle A. Meyer.
|
Social Capital and Community Resilience
|
American Behavioral Scientist
|
2014
|
238
|
Lawrence M. Wein , Yifan Liu.
|
Analyzing a bioterror attack on the food supply: The case of botulinum toxin in milk
|
Proceedings of the National Academy of Sciences of the United States of America
|
2005
|
226
|
Philip J. Peters, Pamela Pontones, Karen W. Hoover
, et al.
|
HIV Infection Linked to Injection Use of Oxymorphone in Indiana, 2014-2015
|
The New England Journal Of Medicine
|
2016
|
Table 3 Top 8 cited articles of Chinese database
|
Count
|
Author
|
Title
|
Journal
|
Year
|
473
|
Zhongwen Ou, Huiyun Wang, Dali Jiang et al.
|
Emergency logistics
|
Journal of Chongqing University (Natural Science Edition)
|
2004
|
177
|
Kaibin Zhong.
|
Review and prospect: construction of emergency management system in China
|
CASS Journal of Political Science
|
2009
|
122
|
Jihong Mo.
|
Legislative situation and characteristics of China’s emergency law
|
Legal Forum
|
2003
|
102
|
Yuchuan Mo.
|
Legal construction of public emergency response in China: legal construction task proposed by SARS crisis management practice
|
Journal of Renmin University of China
|
2003
|
94
|
Yuchuan Mo.
|
The realistic subject of administrative rule of law in public emergency management
|
Jurists Review
|
2003
|
77
|
Yifeng Yang, Chenfang Fan, Guangwen Cao.
|
Emergency management in immediate response to emergent public health event in China
|
Academic Journal of Second Military Medical University
|
2004
|
69
|
Lexuan Luo, Zhanchun Feng, Jian Zhang.
|
Research on the hospital function of response to public health emergency
|
Chinese Hospital Management
|
2004
|
65
|
Liping Fan, Qinghua Zhao.
|
The status quo of emergency management system for sudden public health events in America and Japan and its enlightenment
|
Chinese Nursing Research
|
2011
|