Global Research Status and Development of COVID-19 in 2020: A Bibliometric Analysis

Background: The coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is currently widespread in the world. This study aimed to access the characteristics of the publications involving COVID-19 by using a bibliometric analysis. Methods: COVID-19 publications published between 1 January 2020 and 31 July 2020 was searched from the Web of Science database on 1 August 2020.The database retrieval was done on the same day. Analysis parameters mainly include publication month, research institutions, authors, journals, countries and cooperation networks among them. Results: A total of 14186 COVID-19 associated articles were retrieved from the Web of Science database, and the quantity of articles increased rapidly month by month. The authors of the top ten manuscripts per number of citations and the most productive institution were both from China. The total publication number of China was as high as 3,029 (cid:0) second only to the United States. Moreover, China ranks rst in the number of total citations of articles and the average article citations. The United States has the highest number of total publications and ranks second only to China in terms of the inuence of individual articles. Authors, institutions and Countries established a network of close cooperation for research on COVID-19. Conclusion: There was a growing number of articles on COVID-19 around the world, China and the United States are the two most inuential countries.


Background
COVID-19 was rst reported in Wuhan, China, [1] in December 2019, after that it has spread throughout China and is now a global epidemic. By 2020-08-01, a total of 17396,943 patients had been diagnosed in more than 200 countries, including 675,060 deaths, the United States, Brazil and India are the top three countries with the highest number of infections. [2] The COVID-19 epidemic poses not only a health threat but also a negative impact on the global economy and other aspects. [3] The World Health Organization declared a pandemic in March 2020. [4] Therefore, from the beginning of the epidemic outbreak, a large number of researchers from various countries and institutions Shared a large number of cases, explored solutions, timely formulated guidelines and speci cations, and produced a large number of articles, which played a vital role in the COVID-19 epidemic research and prevention. [5] Bibliometric analysis takes the literature system and its characteristics as the object of study and applies quantitative and qualitative analysis to the publication and citation times of journals and articles. [6] [7] Bibliometric analysis measures the scienti c output of individuals, institutions or countries to represent the current state of the research eld and plays an important role in better understanding the scienti c eld, [8] and it has been widely used to assess scienti c research activities in various elds, including infectious diseases such as Zika virus, [9] Ebola virus disease, [10] [11] Mayaro fever, [12] Leishmaniasis, [13] [14] in uenza, [15] Middle East Respiratory syndrome coronavirus. [16] This paper makes a statistical analysis of COVID-19 related articles published in the Journal of Web Of Science before 2020-08-01 by bibliometric analysis, aim to learn about the critical article in the eld of COVID-19, as well as about the authors, institutions, countries with important contributions and their networks of collaboration with each other.

Data source
The database Web of Science (WoS) was used for retrieval and the retrieval strategy was formulated. Then checked and discussed, when the results of two authors were inconsistent, the third author ruled, and then formulated the nal search strategy. The retrieval terms were (2019-NCOV OR 2019nCoV OR COVID-19 OR SARS-COV-2) AND (2020[PDat] : 2021[PDat]). The time of publication was from January 1, 2020 to July 31, 2020. All the literatures was included in the core collection of Web of Science, including the literatures published online with priority, and the literature types were "ARTICLE" and "REVIEW". Exclude articles such as conference papers, letters and comments; The selection of literature was carried out by two groups on the web page respectively, and inconsistency was checked and dealt with by discussion or by the third group. To avoid errors caused by database updates, all data retrieval, ltering and downloading were completed by August 1, 2020.

Statistical analysis
Statistically analyzed monthly, country, institution, author, and source journals by using the online analysis function of WOS database. R language (Version 1.2.5033) and Bibliometric analysis were used for Bibliometric analysis. [17] Statistical analysis the COVID − 19 related publications growth rule, the number of publications and citations by countries, institutions, journals, and authors, to measure their impact, and analysis collaboration between them (journal articles published by at least two authors from different countries or institutions are de ned as collaboration). Visual analysis with VOSviewer.

Overall publication trends
The search in the Web of Science database resulted in a total of 14186 articles by July 31, 2020. Figure 1 shows monthly trends in publications related to COVID-19 globally, the study just started in January and February, and the total number of published papers was only 329. Moreover, this part of articles was mostly written by Chinese researchers. Since March, it has entered a period of rapid growth and continued to develop rapidly, this may have something to do with the fact that COVID-19 began to be brought under control in China in March, producing a large amount of research results, and the subsequent global outbreak. At present, COVID-19 research has become a global research hotspot.

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As can be seen from Table 1  of citations in the COVID-19 eld were all from China. From the collaboration network among the authors ( Fig. 2(b)), it can be seen that there were close collaborations between these researchers, this is related to the fact that China was the earliest outbreak of COVID-19, and China concentrated its national strength to ght against COVID-19 at that time and achieved periodic victories. Moreover, Chinese in uence in the global ght against COVID-19 is relatively high.
3.4 The top 10 highly productive and in uential institutions in research on COVID-19 eld and collaborations among highly productive institutions As can be seen from Table 2 Figure 3 showed that different institutions form the same country or among different countries both have different levels of cooperation, which re ects the global solidarity and cooperation in the ght against the epidemic.   Table 3) This indicates that these countries are far ahead of other countries in the eld of COVID-19 research. On the one hand, these countries are affected by COVID-19 earlier and more seriously.

Productivity and Collaboration Networks of Countries
On the other hand, they are closely related to the high investment and advanced research of these countries in the eld of COVID-19.

Discussion
In 2020, the global outbreak of COVID-19 not only seriously endangers human health, but also has a great negative impact on the economy and society of various countries. Each country has carried out a lot of research on COVID-19 based on its own capacity and infrastructure, thus generating a large amount of articles.
In this study, as of July 31, 2020, from the Web of Science database retrieved 14186 articles, the number of articles published in January and February was less, because at this time of COVID-19 outbreak early, and mainly outbreak in China, the research on epidemiology, disease course, virus research and epidemic prevention and control were also in the initial stage. Since March, the number of publications has entered a period of rapid growth, and the research results of many countries have also been highlighted.
China was the country most initially affected by the COVID-19 outbreak, has respond quickly to the outbreak at the time, not only positive for disease control and prevention, treatment, and actively in research of COVID-19, More over, has united and organized scientists from all walks of life to race against time to conquer the disease together. China was the rst to isolate and identify the virus strains and In addition, according to the WHO's real-time data on the epidemic situation, the United States, Brazil, India and other countries are the most affected countries. [2] As the country with the largest number of people infected by the epidemic, the United States has also invested a lot in the study of COVID-19, with the highest publication volume, followed by China, Italy and the United Kingdom, and the ranking of the number of citations of articles and the average number of citations of individual articles was second only to China. The top 20 countries contributing to COVID-19 research come from the most affected countries, including China, the United States, the United Kingdom, Iran, Italy, Brazil and so on.
It can be seen from the cooperation networks among important authors, institutions and countries with most numbers of publications and citations that close cooperation networks have been established among authors, institutions and countries, both at home and abroad, and a large number of research results have been produced through cooperation, this was closely related to the WHO call, the strategic direction of countries, and scienti c collaboration in the face of the COVID-19 epidemic. In addition, the COVID-19 epidemic has not been completely defeated, researches on vaccine development, clinical features and therapeutic drugs were still hot spots, and countries still need to maintain close communication and information sharing to speed up the breakthrough in all aspects of COVID-19 research.
Limitations of this paper: The main limitation of this bibliometric analysis was that the literature search relied on a single database, in this paper, Web of Science database is adopted because it is the most complete SCI literature database. More over, there was still the possibility that the author had the same name, although the results had been carefully checked.

Conclusions
During the past eight months of the COVID-19 epidemic, research activity related to COVID-19 increased rapidly. This study shows that in eight months, publications related to COVID-2019 has become more extensive and global. A large amount of publications in the eld of COVID-19 research has come from China, the United States and other countries that have been severely affected by the COVID-19 epidemic.
China and the United States are the two most in uential countries.

Declarations
Ethics approval and consent to participate Not applicable. No ethical approval was required, as this was a bibliometric review for the existing literature.

Consent for publication
Not applicable.

Data availability
The datasets generated during and/or analyzed during the current study are available from the corresponding author at songchangshi81@163.com on reasonable request.

Competing interests
The authors declare that they have no competing interests.