Coronavirus survey ; a bibliometric analysis from 2012-2019


 Background: Coronaviruses have emerged from animal reservoirs over the past decades to create severe illness and death. They are the SARS-CoV, MERS-CoV and more recently, the SARS-CoV2. This study is focused at assessing the characteristics of published works involving SARS-CoV and MERS-CoV at global level; using bibliometric analysis.Methods: Peer-reviewed publications were retrieved from the Scopus database between 2012 and 2019. Data were analyzed in terms of the year, journal and number of publications, international collaboration patterns, research institutes, impact factor, h-index and number of times cited. Visual presentation and analysis of the data were performed using RStudio, Tableau and Microsoft Excel.Results: A total of 1707 research publications were published across the world between 2012 and 2019 with the highest and lowest number of publications in 2016 (288) and 2012 (87). USA had 249 articles, followed by South Korea (186) and Saudi Arabia (111). The total number of citations achieved was 39,094 with Journal of Virology (133) had the highest number of published articles, followed by Emerging Infectious Disease (85) and PLOS One (60).Conclusion: This research showed the international diversity of MERS-CoV and SARS-CoV research with 106 countries. It is also not surprising that United States leads in the number of publications, authors and citations because of its global power and economic strength; this can also be said with the other top countries. Saudi Arabia was among the top rank because of the origination of the MERS-CoV in the middle east.


Background
Coronaviruses are a wide family of enveloped single-stranded RNA viruses that cause mild to severe illnesses in the upper-respiratory tract in mammals and birds; with a high mortality rate [1]. Mild illnesses are cases of common cold predominantly caused by Rhinoviruses, the severe cases cause SARS-CoV, MERS and SARS-CoV-2 [9,10,11]. Coronavirus was rst identi ed by Dr. J. Almeida in 1964 at her laboratory in London St Thomas's Hospital [1,2]. The rst severe outbreak of coronavirus (SARS-CoV) occurred in November, 2002 and ended July 31, 2003; infecting 8,096 humans in 29 countries and regions [3,7]. The second severe outbreak involved the MERS which was rst discovered in September 2012 and has since spread to 27 countries with 2519 cases and 866 deaths [4,7,12] the third and most recent/sever outbreak involved the COVID-19 that was discovered in December 2019 and has spread to 210 countries and regions with over 2.2 million cases and 150, 000 deaths as at April 17, 2020 [5].
Bibliometric tool-works have been largely used to explore the global contributions in several infectious diseases [8]. An up-to-date bibliometric research on SARS and MERS have not been reported in other to know the trends of coronavirus; the aim of this study is to perform an up-to-date global qualitative and quantitative bibliometric analysis of publications in Scopus to reveal the properties of global research output involving SARS-CoV and MERS-CoV before the discovery and outbreak of SARS-CoV-2. Findings from this study will provide a comprehensive view on coronaviruses before the discovery of the recent COVID-19 (SARS-CoV-2). This serves as an important reference for further studies including the research trends on the global pandemic COVID-19. Furthermore, it gives a broad view for editorial journals and authors on future research direction on coronaviruses.

Methods
Publications were retrieved from the Scopus database created and developed by Elsevier in the Netherlands [13,14]. Scopus contains a large database with more than 24,000 titles of which about 20,000 are peer-reviewed journals from about 5,000 international publishers [14,15]. It is known to harbor reliable data and can provide a larger information for analysis when compared to PubMed and Web of Science [14,16]. This study contains only English peer-reviewed research articles retrieved from 2012 till December 31, 2019 with speci ed search terms: "severe acute respiratory syndrome" or "middle east respiratory syndrome" or "MERS" or "SARS" or "coronavirus" or "SARS-CoV" as part of its title, abstract or keywords. Data involving the latest SARS-CoV outbreak (COVID-19) discovered in December 2019 were excluded from this bibliometric analysis. All of these terms are used in one query and retrieved in one day to avoid possible bias that comes from update on the Scopus database due to the constant change in metrics [8, 17,18]. Data retrieved were analyzed quantitively and qualitatively by RStudio (1.2.5001), Tableau (2020.1) and Microsoft Excel (2019); involving the calculation of average, percentages, sum and relative frequencies [22]. Parameters analyzed include year of publications, patterns of international collaboration, country, journals author, keywords research institutions, h-index, impact factors (IF) and times cited [21,22].
The measurement of the impact or productivity of the published researches in SARS-CoV, MERS-CoV, hindex and IF were used as indicators for this bibliometric evaluation. In 2005, Jorge E. Hirsch introduced the h-index as a metric that attempts to evaluate the citation and productivity impact of the publications of a region, scientist or scholar. The IF of the journals reported in the SCImago Journal & Country Rank was used [19,20]. Ranking of the top journals was considered for this study and shown in descending order starting with the 1 st (standard competition ranking) as obtained from the day of retrieval.

Results
In this study, 1707 associated articles were retrieved, with 7444 authors and 39,094 citations at an average of 22.80 citations per documents ( Table 1) Table 2 shows the top countries/territories with the highest number of h-index publications including the number and percentage of their publications with international collaborations. Out of 1707 publications, United States had the highest number of contributors with 249 publications (14.57% of total publications); this was followed by South Korea with 186 publications (10.89% of total publications), Saudi Arabia at 111 (6.50%) publications and China (5.33%). From the top ten countries with the most published articles, Netherlands had the highest publication percentage with international collaboration at 79.17% (19 out of its 24 articles); followed by Hong Kong at 56.09% (23 of its 41 articles) and Saudi Arabia at 54.05 % (60 out of 111 articles) ( Table 2). A network map was created using RStudio to visualize the network distribution and collaboration of countries/territories contributing to the eld of MERS-COV and SARS-CoV research between 2012 and 2019, which is presented in Figure 2, matching the general ranking marks in Table 2.
This shows USA (86) with the highest number of articles with global collaboration, followed by Saudi Arabia (60), China (35), South Korea (27) and Germany (25).
The SARS-CoV and MERS-CoV related articles were retrieved from 509 journals, but mostly in these journals: Journal of Virology (133), Emerging Infectious Disease (85), PLOS One (60) and Eurosurveillance (36); ( Table 3). The impact factor (IF) for the top ten publication ranged from 2. The number of citations in this study was totaled at 39,094 (Table 5) 10,11,21,23]. This trend may be seen in the novel coronavirus pandemic (COVID-19) after a decline in the disease spread due to vaccination or other safety precautions. In 2016, WHO listed MERS-CoV and SARS-CoV as one of several viruses likely to cause epidemic in the future, which gives a possibility for another rise in this research eld in the future since there are no current treatment or prophylactic vaccine to prevent or ameliorate the disease outbreak [6,24].
United States produced the highest number of publications, this is not a surprise because United States have always played a proli c role in general scienti c research from previous bibliometric researches [21,23,25,26]. This may also be due to the focus of the Center for Disease Control and Prevention (CDC) on potential coronavirus threats to humans than any other country [27,28,29]. Another reason is also the size, economic strength and stance of the country as the center of innovation; this can also be said about South Korea and China involvement in MERS-CoV and SARS-CoV research [27,29,30]. These two countries over the years are climbing ranks among the top research countries in the world [31,32,33]. Saudi Arabia, a middle-eastern country, comes out third among the top productive countries; may be due to the origination and outbreak of MERS-CoV from the middle east. These reasons can also be used to justify the high number of citations among these countries; with USA recording the highest followed by Saudi Arabia; with China, South Korea and Hong Kong also featuring among the top ten [ 21,27,29,31,32,34,35].
The Journal of Virology had the most published article in the eld of MERS-CoV and SARS-CoV research, and this is not surprising since the journal specializes on viruses with a high IF of 4.324 [19].
Emerging Infectious Disease, PLOS One, Eurosurviellance and Mbio follow suit; from previous bibliometric studies, these journals are the top-ranking journals in microbial research and may be due to their high IF and the international presence they have in the scienti c research eld [19]. Zaki et al. was the rst (2012) to report the outbreak of MERS-CoV in an article, making it the most cited publication in this research eld. This is also due to the high impact factor (70.67) of the journal it was published in (New England Journal of Medicine) [21,23]. The second most cited publication also featured in the New England Journal of Medicine, reported by Assiri et al. in 2013 [12,21]. This publication reported cases of MERS-CoV in the middle eastern country. Other articles in the top ten cited publications also featured in high impact factor journals with global recognition; which may be the reason for its numerous citations [19]. Previous study showed that a higher IF of a journal result in a higher number of citations and that the most cited publications usually have high IF, which in turn make the IF go higher or stay high [36,37].    The top 20 highly productive and in uential institutions in SARS-CoV and MERS-CoV research eld.

Figure 4
The top ten countries with the highest number of authors. Note: The designations employed and the presentation of the material on this map do not imply the expression of any opinion whatsoever on the part of Research Square concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. This map has been provided by the authors.