Bibliometric Study of World COVID-19 Publication Output

The COVID-19 outbreak originating in Wuhan, Hubei province, China, coincided with chunky, the period of mass migration for the annual Spring Festival. To contain its spread, China adopted unprecedented nationwide interventions on January 23, 2020. These policies included large-scale quarantine, strict controls on travel, and extensive monitoring of suspected cases. However, it is unknown whether these policies have had an impact on the epidemic. We sought to show how these control measures impacted the containment of the epidemic. Web of Science database was searched on September 10, 2020, for COVID-19 publications published between 2019 to 2020. It was performed on the same day to avoid the possible bias from an update on the database because the metrics are changing over time. All publication types were considered; however, publications as errata were excluded. Analysis parameters include a year of publication, publication type, patterns of international collaboration, research institutions, journals, impact factor, h-index, language, and times cited. A total of 17,133 COVID-19 research publications were published across the world. The (COVID-19) associated publications were originated from 25 countries/ territories, indicating the international spread of Corona virus COVID-19 research. The USA was the largest contributor, with 4767 (27.823%) articles published, followed by Peoples R China (2747 (16.033%)) articles.


Introduction
A cluster of viral pneumonia cases of unknown cause, subsequently identified as a novel coronavirus, named as 2019-nCov or COVID-19, was detected on December 31, 2019, in Wuhan, China. The disease has spread rapidly from Wuhan to other regions in China. Further, the dissemination of this virus has been observed in 216 countries and over 680354 deaths as of 2 August 2020 (Aristovnik et al., 2020). Bibliometric evaluation, a commonly accepted statistical tool, helps to present the knowledge structure of a particular research field. Throughout recent years, bibliometrics has been used to provide strong insights into several biomedical fields linked to many virus outbreaks (Al-Jabi, 2017;Hagel et al., 2017;Wu et al., 2020;Zyoud, 2016). There have been a few recent reviews of COVID-19 or Coronavirus (Zhou et al., 2020). The previously published bibliometric studies on COVID-19 have been published by using the Web of Science (WoS) database for data collection and were limited to biomedical research areas (Wu et al., 2020). Therefore, the purpose of the current COVID-19 research during the early stage of the outbreak through bibliometric analysis (Aristovnik et al., 2020b) determine the top-cited publications, and explore the current topics to provide the scientists and researchers hot topics to provide the scientists and researchers with a resource that can help them by identifying the current research priorities. (Joshua & Sivaprakasam, 2020).

Data Source & Methods
For this study, bibliometric data were collected from the Science Citation Index Expanded, Social Sciences Citation Index, and Emerging Sources Citation Index databases within the Web of Science (WoS) core collection. These databases within WoS are maintained by Clarivate Analytics, which offers the world's leading scientific citation search and analytical information platform18. Collectively WoS collection provides enriched bibliometric data useful for citation analytics and mapping the knowledge in a given domain by examining leading authors, institutions, and collaborating nations working in a given domain of scientific research. The following query was administered to retrieve COVID-19 related bibliometric data: "Novel coronavirus" OR "Novel coronavirus 2019" OR "2019 Novel coronavirus" OR "2019 nCoV" OR "COVID-19" OR "Wuhan coronavirus" OR "Wuhan pneumonia" OR "SARS nCoV" OR "SARS-CoV-2". Considering the timing of the outbreak in late 2019, the search strategy was limited to 2019-2020 to retrieve data that may contain publications on COVID-19 rather than earlier coronaviruses. All search fields were selected, including topics, titles, and abstracts, to retrieve the bibliometric data ensuring the sensitivity of the search strategy. This search was conducted on September 10, 2019; no restrictions on languages or publication types were applied due to the low number of publications on this recent topic. The inclusion criteria for this bibliometric study was as follows: a) journal articles published on COVID-19 topic, b) language of the publication was English, c) articles irrespective of their methodology were included, d) studies published between January 1, 2019, to September 2020, were included.
Furthermore, articles were excluded if they had conflicts with any of the above-mentioned inclusion criteria. The references of the retrieved articles were not evaluated. Therefore, articles retrieved through citation search are the only source of data in this bibliometric study. VOSviewer (van Eck & Waltman, 2010) (version 1.6.10) was used to analyze the Coauthorship, Co-occurrence, Citation, Bibliographic coupling, Co-citation, and themes.

Data Analysis and Results
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Forms used for Communicating COVID-19
Table 1 and Figure 1 illustrate the forms used for communicating COVID-19 research; these include articles published in scholarly journals, conferences and seminar proceedings, reviews, editorial materials, book chapters, meeting abstracts, etc. The study observed that a total of 17133 research publications in COVID-19. The majority of publications are published in Journal Articles, i.e., 6882 (40.168%) followed by Early Access 4378 (25.553%) publications, Editorial Material 4179 (24.392%) publications, 3825 (22.325%) published as Letters, 1546 (9.024%) publications are published as Review and also observed from the data that more than 99% of articles published in the English language.

Distribution of Articles among Sub-Disciplines
The World literature about COVID-19 published during 2020 ware extracted from the Web of Science citation database and classified under 20 major sub-disciplines.    Table 4 and figure 4 reveals the top productive sources preferred by the authors in COVID-19 research publications. They cover around one-fifth (19%) of total documents and cover more than 50% of total citations. The majority of these journals are subject to health sciences, and they are classified mainly in the following sub-disciplines: infectious diseases, general medicine, and medical sciences.  Figure  5 shows the VOS viewer Citation network of most productive journals.  show the Co-authorship network of most productive organizations and the Citation network of most productive organizations.   Table 6 Shows the highly productive authors of COVID-19 related articles, total citations, and h-index during the study period. The first one is, Wang Y contributed 92 (0.537%) publications followed by Li Y 76 (0.444%), Wang J 75 (0.438%), and Li W placed last in the table with 41 (0.239%) publications. Liu Y was got 4831 total citations with 18 h-index, followed by Wang Y 1471 with 17 h-index. Liu L, Wang J, Zhang Y, Wang L were having 16, 15, 15, 14 h-index, respectively.

International Linkages of COVID-19
The geographical distribution of articles presented in Table 7, which gives the country wise-distribution of research publications contribution. Out of 17133 research articles, the USA contributed the highest number of research articles, 4767 (27.823%), followed by China with 2747 (16.033%), Italy with 2136 (12.467%), England with 1913(11.166%), Canada with 861 (5.025%), Germany with 801 (4.675%) and India with 751 (4.383%) publications. Figures 9 & 10 show the Co-authorship Countries network and the Citation network of countries.

Highly Prolific Keywords Network
The keywords in the 17133 publications measured in the present study were analyzed using VOSviewer (Figure 11). A total of 25 keywords identified as having occurred more than 90 times in the title and abstract fields across all articles. These keywords appeared in all publications; the study was classified as clusters. Covid-19 (6180 times) was used, followed by sars-Nov-2 (1926 times) and coronavirus (1570 times). Seventeen keywords were used 100 to 1000 times, and five keywords were used 90-100 times, respectively (Table 9).