Impact of COVID-19 on Children and Adults: A Bibliometric Assessment of Global Publications

The paper presents a analysis of quantitative and qualitative dimensions of global research output (3488 records) on "Impact of COVID-19 on Children and Adolescents", based on indexed publications in Scopus database. The global publications on this theme averaged 8.31 citations per paper. About 1.49% share of its total publications in this area received external funding support. The 145 countries partcipitated in global research output on "Impact of COVID-19 on Children and Adults", of which the top 10 countries accounted for 85.21% and more than 100% share of global publications and citations. The USA, U.K. and Italy leads in global publications ranking and productivity as against China (3.16), U.K (1.28) and USA (1.27) leading in terms of relative of relative citation index. The 412 organizations and 661 authors participated in global research on this theme, with top 15 most productive organizations and authors contributing 21.07% and 4.30% global publications share and 38.05% and 12.98% global citations share. Harvard Medical School, USA, Huazhong University of Science and Technology, China and Tongji Medical College, China leads the world as the most productive organizatons (with 480, 67 and 63 publications) and Huazhong University of Science and Technology, China (31.97 and 3.85), Tongji Medical College, China (19.92 and 2.40) and Children Hospital of Philadelphia, USA (19.30 and 2.32) leading as the most impactful organizations in the world in terms of citation per paper and relative citation index. D. Buonsensov, C. Calvo and X. Lu were the most productive authors (with 15, 12 and 12 papers) and X.Lu (103.83 and 12.49), A. Licari (40.11 and 4.83) and G.L. Marseglia(34.09 and 4.1) were the most impactful authors. JAMA Pediatrics, Pediatrics Infectious Disease Journal and Acta Paediatrica International Journal of Pediatrics were the most productive journals (with 71, 60 and 58 papers) and Pediatrics (36.59), JAMA Pediatrics (19.49) and Acta Paediatrica International Journal of Pediatrics (14.93) were the most impactful journals.


INTRODUCTION
Coronavirus disease 19 (COVID-19), originated at Wuhan city of China in early December 2019 has rapidly widespread with confirmed cases in almost every country across the world and has become a new global public health crisis. The etiological agent was designated as Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The virus was originated in bats and human transmission primarily occurs through direct, indirect, or close contact with infected people through infected secretions such as respiratory secretions, saliva or through respiratory droplets that are expelled when an infected person coughs, sneezes, or speaks. The World Health Organization coined the term COVID-19 and declared this novel coronavirus disease as a pandemic on March 11, 2020. The virus infects the human respiratory epithelial cells by binding through Angiotensin-Converting Enzyme 2 (ACE2) receptors. The major clinical symptoms of the disease are fever, non-productive cough, fatigue, malaise and breathlessness. Severe illness such as pneumonia, acute respiratory distress syndrome (ARDS), and death occurs in the elderly and patients with comorbid conditions. 1 Globally, as 15 May 2021, there have been 161,513,458 confirmed cases of COVID-19, including 3,352,109 deaths, reported to WHO from 213 countries and territories. 2 There are more than 2.2 billion children in the world who constitute approximately 28% of the world's population. Those aged between 10 to 19 years make up 16 % of the world's population (UNICEF, 2019). Of all COVID-19 cases reported worldwide last year, children under 18 years accounted for about 8%, despite comprising 29% of the global population, according to the World Health Organization. 3 Children of all ages can get COVID-19. Children, particularly those younger than 12 to 14 years of age, appear to be affected less commonly than adults, although children typically have a lower risk of exposure than adults and are tested less frequently than adults. In surveillance from various countries children typically account for up to 15 percent of laboratory-confirmed cases. 4 To date, data on COVID-19 in children and International Journal of Medicine and Public Health, Vol 11, Issue 3, Jul-Sep, 2021 adolescents remain scarce, despite the number of confirmed COVID-19 cases now exceeding 8 million globally. Nevertheless, a small proportion of children and adolescents develop severe disease and require ICU support, frequently needing prolonged ventilatory support. However, fatal outcome is rare overall. 5 The unexpected disruption of the social fabric and norms has affected the behavioral and mental health of the public, including children. The mental health of children has been influenced by several ways, as this unprecedented situation changed a way they typically grow, learn, play, behave, interact, and manage emotions. Children with pre-existing psychiatric disorders such as attention-deficit/hyperactivity disorder (ADHD), anxiety, depression, mood disorders, and behavior disorders could be adversely impacted during this stressful situation. 6 The COVID-19 pandemic is harming health, social and material well-being of children worldwide, with the poorest children, including homeless children and children in detention, hit hardest. School closures, social distancing and confinement increase the risk of poor nutrition among children, their exposure to domestic violence, increase their anxiety and stress, and reduce access to vital family and care services. Widespread digitalisation mitigates the education loss caused by school-closures, but the poorest children are least likely to live in good home-learning environments with internet connection. Furthermore, increased unsupervised on-line internet use has magnified issues around sexual exploitation and cyber-bullying. 7 COVID-19 affects all components of the respiratory system, including the neuromuscular breathing apparatus, the conducting airways, the respiratory airways and alveoli, the pulmonary vascular endothelium, and pulmonary blood flow. Viral pneumonia is the most frequent serious clinical manifestation of COVID-19, prominently featuring fever, cough, dyspnea, hypoxemia, and bilateral infiltrates on chest radiography. Dry cough is more common than a productive cough. Dyspnea appears after a median time of 5 to 8 days. Severe hypoxemic respiratory failure consistent with the Berlin definition of the acute respiratory distress syndrome (ARDS) occurs in a significant proportion of patients with COVID-19 pneumonia..While the pulmonary system is most commonly affected, extrapulmonary clinical manifestations of COVID-19 exist and affect multiple other organs and organ systems including cardiovascular, renal, hepatic, gastrointestinal, ocular, dermatologic, and neurological systems, which could have significant health consequences. 8,9 Bibliometrics, together with novel visualization methods of scientific information, have been used here which is helpful in identifing emerging outbreaks of infectious disease. Bibliometrics is also recognized as an essential tool and is widely used in a variety of fields to measure and evaluate scientific research quantitatively and qualitatively. 10

Literature Review
Athough several bibliometric studies have been recently carried output on global and national output of Coronovirus research as well as on COVID-19. One recent study was undertaken by Monzani, Tagliaferri, Bellone, Genoni and Rabbone, 11 which analysed 2301 global publications on COVID-19 in pediatric age using data from Scopus database during January 1, 2020 and June 11, 2020. A bibliometric methodology was applied to evaluate the total number of papers and citations, journal and publication types, the top-productive institutions and countries and their scientific collaboration, the core keywords. Grover, Gupta amd Mamdapur 12 carried out another bibliometric study on the "Impact of COVID-19 on Mental Health of Children and Adolescents, which studied 1787 global papers indexed in Scopus database duting 2020-21. Since no recent comprensive study was available on this topic, we decided to undertake the present study on the "Impact of COVID-19 on Children and Adults" using bibliometric methods to understand bibliometric characterstics of global literature and to study the research trends. It also evaluates the performance of global countries, organizations, authors and journals, besides identifying the scatter of literature across broad subjects and keywords for understanding the research trends. The study used indexed publications data till 1 May 2021 from Scopus databases

MATERIALS AND METHODS
For this study, the global publications on the "Impact of COVID-19 on Children and Adolescents" were identified, retrievied and downloaded from the the Scopus database (http://www.scopus.com) on 1.5..2021 using a well conceived search strategy. Here a set of two types keywords related to "COVID-19" and "Children or Adolescents" were used in "Keyword tag" and in "Article Title tag" (joined by Bolean operator "OR") of the Scopus database, yielding 3488 global records. The search strategy was further refined first by country to get publication output data of top 10 countries and secondly to get statistics on global output by subject, collaborating country, organization, author and journal. Citations to publications were counted from date of their publication till 1.5.2021. TITLE ( "COVID 19" OR "2019 novel coronavirus" OR "coronavirus 2019" OR "coronavirus disease 2019" OR "2019-novel CoV" OR "2019 ncov" OR covid 2019 OR covid19 OR "corona virus 2019" OR ncov-2019 OR ncov2019 OR "nCoV 2019" OR 2019-ncov OR covid-19 OR "Severe acute respiratory syndrome coronavirus 2" OR "SARS-CoV-2" ) OR KEY ( "COVID 19" OR "2019 novel coronavirus" OR "coronavirus 2019" OR "coronavirus disease 2019" OR "2019-novel CoV" OR "2019 ncov" OR covid 2019 OR covid19 OR "corona virus 2019" OR ncov-2019 OR ncov2019 OR "nCoV 2019" OR 2019-ncov OR covid-19 OR "Severe acute respiratory syndrome coronavirus 2" OR "SARS-CoV-2" ) and TITLE (CHILD* OR INFANT OR ADOLESCENT)

Top Ten Most Productive Countries
The 145 countries took part in global research on "Impact of COVID-19 on Children and Adolescents" and their distribution was uneven: 93 countries published 1-10 papers, 36 countries published 11-50 papers, 4 countries published 51-100 papers and 12 countries published 104-941 papers each. The top 10 most countries among 145 partcipitating countries, contributed 117 to 941 papers and together contributed 85.21% share of global publications outout and more than 100% share to global citation output.. USA, U.K., Italy and China are the top ranking countries with global publication share of 26.98%, 11.41% and 10.92% respectively, followed by India (6.34%), Canada, Spain, Turkey, Australia and France (from 3.35% to 4.96%). China (3.16), U.K (1.28), USA (1.27), France (1.22), Italy (1.15) and Australia (1.08) registered relative citation index above 1.0 The share of international collaborative papers in global output of the top 10 countries varied from 13.60% to 61.29%, with average value as 33.48% during 2020-21 (Table 1).  Table 2).

Subject-Wise Distribution of Global Research Output
Among 9 broad subjects (as identified in Scopus database) contributing to research on "Impact of COVID-19 on Children and Adolescents' , Medicine contributed the largest publication share (83.89%) to global output, followed by Psychology (10.24%), Social sciences (7.68%), and other five subjects contributing less than 5.0% (from 1.58% to 4.90%). Environment Science registered the largest citation impact per paper (10.81) and least by Pharmacology, Toxicology and Pharmaceutics (4.47) ( Table 3).

Top 15 Most Productive Organizations
In      (Table 8).

High Cited Papers
Of the total global output in "Impact of COVID-19 on Children and Adolescents" (3488 publications), only 52 (1.49% share) accumulated 101 to 1167 citations per paper (cumulative total 13345 citations) since their publication during 2020-21, averaging to 256.63 citations per paper. The distribution of these 52 highly cited papers is skewed: Twenty seven papers registered citations in the range 101-194 per paper, 11 papers were in citation range 203-287, 9 papers in citation range 303-498, 4 papers in citation range 519-880 and 1 paper received 1167 citations. Of the 52 highly cited papers, 23 were published as articles, 10 as letters, 9 as reviews, 6 as notes, and 2 each as short surveys and editorials. Of the 52 highly cited papers, 8 resulted from contribution by single organizations per paper (non-collaborative papers) and 44 from two or more organizations per paper (32 national collaborative and 12 international collaborative papers).

SUMMARY AND CONCLUSION
Using quantitative and qualitative indicators, the present paper provides a bibliometric assessment of global literature (3488 records) on "Impact International Journal of Medicine and Public Health, Vol 11, Issue 3, Jul-Sep, 2021   Medicine contributed the largest share (83.89%) to gobal publications output on on "Impact of COVID-19 on Children and Adolescents' , followed by Psychology (10.24%), Social sciences (7.68%), and other five subjects contributing less than 5.0% (from 1.58% to 4.90%). The major focus of global research on "Impact of COVID-19 on Cildren and Adolescents" has been on mental health related disorders (51.55%), followed by respiratory related disorders (17.06%) and the rest on extrapulmonary manifestions of COVID-19 disease. The 412 organizations and 661 authors participated in global research on this theme, with the top 15 most productive organizations and authors