In late December 2019, a cluster of cases with pneumonia caused by an unknown etiology was reported from Wuhan, Hubei Province, China. Reference Huang, Wang and Li1 Later, the cause of the disease was identified as a novel betacoronavirus, the 2019 novel coronavirus (2019-nCoV). The disease was coined as coronavirus disease 2019 (COVID-19). Recently, the official name of the virus that causes COVID-19 has been announced by World Health Organization (WHO) as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). 2
Scientometrics, also known as “Science of science,” is a popular statistical method analyzing scientific literature thoroughly in a certain field. Reference Hood and Wilson3 The academic literature lacks an in-depth scientometric study evaluating coronaviruses and disease caused by them. Herein, we aimed to perform a holistic scientometric assessment of the coronavirus literature.
METHODS
Our main source of this study was Web of Science (WoS, Thomson Reuters, New York, NY) Core Collection database. We preferred WoS as our main data source because it provides data analysis for publications and citations and allows the results to be sorted according to the number of citations. In addition, WoS attribution data are considered more reproducible and reliable than other databases, and WoS is used as the standard by certain official organizations. Reference Kendall4 We used keywords of “coronavirus,” “SARS”, “SARS-CoV”, “MERS”, “MERS-CoV”, and “COVID-19” for our analysis. All items published between 1980 and 2019 were included, and documents produced in 2020 were excluded for our major analysis. A distribution map of global production of coronavirus literature was generated by a free Web source named GunnMap. 5 VOSviewer freeware was used to create scientometric networks. 6
RESULTS
General Features of Coronavirus Literature
A total of 13,833 documents indexed in WoS Core Collection between 1980 and 2019 were found in coronavirus literature, 7339 of which were open access. The peak year for publication was 2016 with 837 papers and 106 articles have been produced in 2020 so far. English was the major language of coronavirus literature (96.957%) followed by French, German, Spanish, and Chinese (0.802, 0.766, 0.289, and 0.231, respectively). Original articles covered 80.518% with 11,138 documents of all coronavirus literature followed by reviews, proceeding papers and editorials (8.545, 4.634, and 2.704%, respectively; Table 1). Virology, Veterinary Sciences, and Infectious Diseases were the most studied areas in literature (Table 1).
TABLE 1 Features of Coronavirus Literature a
a Total percentage may exceed 100% because certain items were included in more than 1 category.
b Of total documents published in coronavirus disease literature.
Performances of the Countries, Authors, Institutions, and Sources
The United States of America (USA) ranked first in coronavirus literature with 4894 articles (35.379%) followed by China, Germany, the United Kingdom (UK) and the Netherlands (16.663, 6.701, 6.448, and 5.711%, respectively). Publications in coronavirus literature have been produced from almost every country in the world, except for some countries in Asia and Africa (Figure 1). Yuen from the University of Hong Kong (China) was the most prolific author with 218 indexed papers (1.576%, Table 1). University of Hong Kong was also detected as the most productive institution in the literature with 534 publications (3.86%; Table 1). Journal of Virology, Virology and Advances in Experimental Medicine and Biology were the most contributor source titles in coronavirus literature (N = 1166, 510, and 370 items, respectively; Table 1).
FIGURE 1 Publication Density of World Countries in Coronavirus Literature.
Citations, Decades, and Scientometric Networks Analyses
1980-1989
Our search yielded 641 articles in the period of 1980 to 1989. The United States, Federal Republic of Germany, the United Kingdom, Canada, and France dominated coronavirus literature in this period (36.661, 13.417, 12.168, 9.204 and 7.8, respectively). The most prolific author was Termeulen V with 37 items. The Journal of General Virology and University of Würzburg (Germany) stood out in their categories in this period. H-index of coronavirus literature for this period was calculated as 79 and total number of citations was 21,682 (18,643 without self-citations). Average citations per item were 33.83. The most cited document in this period was an original article titled “Characterization of An Efficient Coronavirus Ribosomal Frameshifting Signal - Requirement for An RNA Pseudoknot” written by Brierley et al. (Table 1).
1990-1999
Coronavirus literature had 1674 documents indexed between 1990 and 1999. The United States, Germany, Canada, the United Kingdom, and the Netherlands were the most productive countries between 1990 and 1999 (44.265, 8.961, 8.303, 8.244, and 7.826, respectively). Lai from University of Southern California (USA) was the most prolific author with 70 documents. The Journal of Virology was the prominent source title in this decade with 226 articles (13.501%), and University of Southern California (USA) was the most contributor institution with 96 papers (5.735%). H-index was measured as 105 and published documents were cited 63,445 times in this period (53,214 without self-citations). The most cited document was an original article titled “Community Study of Role of Viral-Infections in Exacerbations of Asthma In 9-11-Year-Old Children” by Johnston et al. (Table 1). As we analyzed scientometric network analysis of coronavirus literature in this period the most indexed keywords were detected to be “coronavirus,” “mouse hepatitis virus,” “transmissible gastroenteritis virus,” “rotavirus,” and “cat” (Table 1).
2000-2009
A total of 4810 documents was produced in coronavirus literature between 2000 and 2009, and 82.682% of all items were original articles. The United States, China, Canada, Germany, and Netherlands were the most productive countries (N = 1679, 1202, 324, 322, and 278 papers, relatively). University of Hong Kong (China), Chinese Academy of Sciences (China), and Chinese University of Hong Kong (China) were the most contributor institutions in this period (5.925, 4.595, and 3.576%, respectively). Yuen form the University of Hong Kong (China) was the most prolific author with 110 papers (2.287%) and the most productive source titles were detected to be Journal of Virology, Virology and Advances in Experimental Medicine and Biology (10, 3.493 and 3.222%, respectively). H-index for this decade was 165 and total number of citations was 189,424 (135,829 without self-citations). Average citations per item were 39.38. The most cited article in this period was an original article written by SARS Working Group, Ksiazek et al., titled “A novel coronavirus associated with severe acute respiratory syndrome” published in The New England Journal of Medicine in 2003 (Table 1). The most indexed keywords were detected to be “coronavirus,” “SARS-CoV,” and “spike protein” (Table 1). Scientometric network map of the most used keywords showed a starburst pattern in which the keywords of “coronavirus,” “SARS,” “SARS coronavirus,” and “SARS-CoV” centered.
2010-2019
The decade of 2010s was the most active period of the literature with 6601 documents. Most documents (N = 4146; 62.8%) were open access and 80.7% of all items were original articles. The United States, producing 33.586% of all coronavirus literature, ranked first as ever, followed by China, Germany, Saudi Arabia, and The United Kingdom (22.406, 6.575, 6.454, and 6.166%, respectively). University of Hong Kong (China), National Institutes of Health (USA), Chinese Academy of Sciences (China), and University of California System (USA) stood out from the rest (3.681, 2.787, 2.575, and 2.439%, respectively) and Drosten from Charité – Universitätsmedizin (Germany) was the most prolific author of this period with 113 articles. A total of 6111 articles were analyzed for the citation analysis. H-index of this period was measured as 106. Indexed documents were cited 109,418 times (53,521 times without self-citations). An original article titled “Isolation of a Novel Coronavirus from a Man with Pneumonia in Saudi Arabia” written by Zaki indexed in The New England Journal of Medicine in 2012 (Table 1). The most indexed keywords were “coronavirus,” “MERS-CoV,” “epidemiology,” and “SARS-CoV” (Table 1). Scientometric network analysis of keywords revealed relative keywords such as “Saudi Arabia,” “MERS-CoV,” “outbreak,” vaccine,” “camel,” and “zoonosis.”
Update for 2020 and COVID-19 (SARS-CoV-2)
By the date of the writing of this study (May 15, 2020), 6679 documents were indexed relevant to CoVid-19 in PubMed and 4605 items were included in WoS databases. All included documents were published and indexed in 2020. Total number of open-access coronavirus articles produced in 2020 was 4605. China ranked first with 1184 documents (25.711%) followed by the United States, the United Kingdom, Italy, Germany, India, Canada, Australia, France, Iran, Switzerland, Brazil, and South Korea (23.822, 9.511, 9.186, 4.039, 3.757, 3.735, 3.648, 3.409, 3.062, 2.953, 2.323, and 2.237%, respectively). The most contributor institutions were University of London (UK), Huazhong University of Science Technology (China), Harvard University (USA), University of California System (USA), Wuhan University (China), University of Hong Kong (China), Chinese Academy of Sciences (China), Zhejiang University (China), University of Oxford (UK) and Fudan University (China) (3.149, 2.758, 2.193, 2.172, 2.041, 1.781, 1.694, 1.607, 1.433, and 1.39%, respectively). Major source titles for 2020 were Lancet, British Medical Journal, Journal of Medical Virology, Nature, Science, and Cureus (N = 135, 119, 108, 95, 89, and 78 items, respectively).
DISCUSSION
It is important to analyze the coronavirus literature based on periods, because it helps us understand the progression of the disease. In the 1980s, the United States and developed countries from Europe were major source countries. During this period, the virus was identified only as an animal disease in the literature, and its biological and genetic structure was investigated. In the second decade we investigated (1990s), the United States and European countries stood out again and the coronaviruses started to be examined in terms of whether it affected the health of animals and people with asthma (Table 1). In fact, in this period, the effects of these viruses on the human respiratory system were underlined in the literature and perhaps early measures could be taken for a possible global eradication of coronaviruses. Of course, this is just our hypothetical and speculative interpretation.
The 2000s can be called as the SARS period in the coronavirus literature. In November 2002, a novel respiratory system disease coined as SARS was identified in China caused by SARS-CoV. This disease caused global anxiety, because it progressed through an outbreak and epidemic in 26 countries and more than 8000 people were affected. Reference Wilder-Smith, Chiew and Lee7 In the literature of the 2000s, China became a major contributor of coronavirus literature because the SARS outbreak originated from Guangdong province of southern China. Almost all most-cited publications in this period are related to SARS and ACE2 protein. SARS-CoV is “thought to be an animal virus from an as-yet-uncertain animal reservoir, perhaps bats, that spread to other animals (civet cats)” according to WHO. We want to draw attention to one of the most cited articles in this period titled “Bats are natural reservoirs of SARS-like coronaviruses” written by Li et al. published in Science in 2005 (Table 1). The authors reported that species of bats were a natural host of coronaviruses closely related to those responsible for the SARS outbreak. In the conclusion paragraph of this manuscript, Li et al. suggested in-depth investigation of reservoir host distribution, animal-animal and human-animal interaction (particularly within the wet-market system), and analyzing genetic diversity of bat-borne viruses to avoid future outbreaks. Reference Li, Shi and Yu8
In April 2012, a novel lethal zoonotic pathogen, MERS-CoV, was identified in humans in Saudi Arabia and Jordan. A total of 2499 confirmed cases and 858 deaths (mortality rate, 34.3%) were reported from 27 countries. Outbreaks caused by human-human transition in Saudi Arabia in 2014 and South Korea in 2015 occurred. Reference Memish, Perlman and Van Kerkhove9 In 2010s, Saudi Arabia became one of the major sources in coronavirus literature. Almost all most-cited articles were related to MERS in this period.
We found only one scientometric document relevant to coronavirus literature. It was a letter with limited data and no tables or images revealing scientometric networks. The authors reported that the United States and China had primary roles in the literature. Reference Bonilla-Aldana, Quintero-Rada and Montoya-Posada10
CONCLUSIONS
In late 2019, a novel coronavirus causing SARS-like pneumonia was identified. This novel virus was temporarily named as SARS-CoV-2 and the disease has been coined as COVID-19 by the WHO. 2 By the date of writing this study, a total of 167,682 confirmed patients and 6456 deaths were reported from 157 countries and territories, and the COVID-19 outbreak has been officially declared as pandemic. We hypothesized that the COVID-19 pandemic could be prevented if the suggestions of the articles previously published, such as that by Lie et al., were taken into consideration and the wet-markets were completely closed to cut off the human-animal interaction. Scientometric studies should be performed in certain diseases that previously caused epidemics to prevent global spread in the future and to take urgent measures.
Conflict of Interest
None declared.
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