Bibliometric analyses of COVID-19 research

Applications for the bibliometric Co-occurrence analysis:

Offers an overview of:
- the structure of topics investigated,
- the relative focus, as measured by the number of occurrences, shown as the size of nodes.
- The different colors indicate different general research foci.
Identifying the most relevant search terms.
- The keywords in the map are those commonly used by article authors, with differences across the research areas. Identifying the most relevant terms can help narrow the search to the most relevant articles.

To access the interactive map, you need to open the graph in VosViewer, which allows you to search the map, see what keywords are connected, and the strength of the connection between each node in the graph diagram. To open the map in VosViewer, Please click here, and allow it to download, then open the file and allow Java to run. For a video demonstration of how to do this, please see here.

For more information about what a bibliometric keyword co-occurrence analysis is, please see the About page. The data is downloaded from PubMed.

Insights and trends

Some insights from the weekly bibliometric keyword co-occurrence analyses conducted since March 2020 include that there has been a very rapid increase in COVID-19 literature. From 992 on March 16th, when we initiated this project, to over 50 000 now. Below we refer to some insights and trends. For more details, please read the individual blog posts.

Early in the pandemic, the research focus, based on 1323 publications on March 23rd, was on topics within “Health and pandemic management,” “The disease and its pathophysiology,” “Clinical epidemiology of the disease,” and “Treatment of the disease”. Please see the preprint for a more detailed description

About a month later, on April 20th, the number of publications had increased with 395%; to 5228. Moreover, the research landscape had changed somewhat. The topics studied can be described as 1) «A global virus pandemic» including topics within “preventive epidemiology” and “care management.” 2) “Disease epidemiology,” 3) “Pathophysiology and origin,” including topics within “viral biology” and “drug treatment”, 4) “Clinical epidemiology”, and 5) a fifth cluster includes topics on mental health and attitudes. The topic of mental health starts to emerge as a research focus within the COVID-19 pandemic research. During March and April, several countries have introduced strict social distancing measures to reduce the spread of the covid-19 virus. New research focuses on how the pandemic affects people’s mental health and feelings of isolation and loneliness. For more details, click here

On July 23rd, the focus of the most recent literature was on 1) Public health strategies, treatment, and the global impact of COVID-19, 2) the role of existing drugs and vaccines in the current pandemic, 3) demographics and risk factors, 4) literature concentrated on understanding the nature of the virus, and 5) COVID-19 and mental health. For more details, check out this post

For an illustration of the change in research trends across the very early stages of the pandemic and later stages, please see our post from September 23rd: Click here

Growth in number of documents by week:

Date	Nr. of docs in PubMed
16th March	992
23rd March	1323
30th March	1788
6th April	2684
13th April	3683
20th April	5228
27th April	6958
04th May	8791
11th May	11005
18th May	13103
25th May	15438
01st June	17356
08th June	19426
15th June	22147
22nd June	24167
29th June	26187
06th July	28256
13th July	30116
20th July	32262
27th July	33970
03rd August	36201
10th August	38271
17th August	39914
24th August	41913
31st August	46037
7th September	48067
14th September	50057
21st September	52105
28th September	53994

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to September 28th, 2020.

by Ingunn Olea Lund | Sep 28, 2020 | CoOccurrence

Corpus downloaded from PubMed September 28th consisted of 53994 publications. There were 3300 keywords that occurred in five or more manuscripts. The keywords divided into five main clusters. To create the map, we used the LinLog method. The minimum cluster size was set to 30.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
public health	pneumonia	pandemic	sars	female
telemedicine	mortality	coronavirus infection	animals	male
epidemiology	hydroxychloroquine	viral pneumonia	antiviral agents	middle aged
mental health	inflammation	betacoronavirus	viruses	adult
epidemic	ace2	china	zoonosis	aged
personal protective equipment	infection	disease outbreaks	mers	children
anxiety	cytokines	infection control	peptidyl-dipeptidase a	clinical laboratory techniques
infectious diseases	acute respiratory distress syndrome	quarantine	vaccine	young adult
depression	chloroquine	united states	spike glycoprotein, coronavirus	adolescent
outbreak	treatment	global health	respiratory infections	risk factor
health policy	critical illness	italy	antibodies, viral	retrospective studies
social distancing	hypertension	travel	diagnosis	tomography, x-ray computed
prevention	cardiovascular diseases	surveys and questionnaires	viral vaccines	aged, 80 and over
transmission	cytokine storm	health personnel	genome, viral	lung
india	ards	time factors	clinical trials as topic	infant
social media	diabetes mellitus	risk assessment	phylogeny	comorbidity
stress	stroke	critical care	chiroptera	treatment outcome
lockdown	obesity	cross-sectional studies	wuhan	fever
cancer	remdesivir	practice guidelines as topic	antibody	child, preschool
healthcare workers	thrombosis	contact tracing	antibodies, monoclonal	severity of illness index
triage	lopinavir	world health organization	receptors, virus	pregnancy
risk	diabetes	delivery of health care	immunization, passive	hospitalization
safety	tocilizumab	brazil	host-pathogen interactions	prognosis
surgery	angiotensin-converting enzyme inhibitors	united kingdom	alanine	intensive care units
education	acute kidney injury	communicable disease control	drug repositioning	real time polymerase chain reaction

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graphs comparing COVID-19 research focus in the very early stages (up to March 23rd, 2020) to the focus in August 2020.

by Ingunn Olea Lund | Sep 23, 2020 | CoOccurrence

In this post, we compare the focus of the COVID-19 literature published in the very early stages of the pandemic (up to March 23rd) to the focus of literature published during August 2020.

The first graph below is based on the literature based on the Corpus downloaded from PubMed 23rd March. The literature consisted of 1323 publications, of which there were 225 keywords that occurred in three or more manuscripts. These divided into four clusters, that are described in this preprint

The second graph below is based on COVID-19 literature published during August 2020. The literature consisted of 10901 publications, of which there were 1179 keywords that occurred in 5 or more manuscripts. The keywords divided into five main clusters. To create the map, we used the LinLog method. The minimum cluster size was set to 15. We provide a brief description of the clusters from the August COVID-19 litterature: Within cluster 1 (red), the “Pandemic of viral pneumonia; public health and world spread”, we found topics relating to “Public health concerns” “health personnel, education and behavior”, “Guidelines and health care”, and “vulnerabilities in health care”. Cluster 2 (green), “Treatment of COVID-19”, include topics relating to “Epidemiology of virus transmission” “Antiviral agents and vaccines”, “Cancer and chemotherapy”, “Angiotensin and diabetes” and “Antibodies and passive immunization” Central themes in cluster 3 (blue), “Epidemiology of the pandemic and disease”, are “Respiratory illness and care”, “Risk factors and mortality”, “Clinical investigation and diagnosis” and “Population epidemiology”. Central themes in cluster 4 (yellow), “Surveys of disease and mental health”, are topics relating to “Population surveys and anxieties” and “Health care and migration”. Cluster 5 (purple), is dominated by one single theme, namely topics relating to “Lab-work and diagnostics”; which is also what we labeled this cluster.

When inspecting and comparing the network graphs illustrating the COVID-19 literature published during August and one published during the early phase (January 1^st – March 23^rd, 2020), we notice some consistent themes, and some emerging themes. Much of what was being covered during the early phase is still in focus. For instance, the topics from the “health and pandemic management” cluster from the early phase is reflected in the topics covered in the “Pandemic of viral pneumonia; public health and world spread” cluster in the August literature network graph. Early in the pandemic, there was not however, a focus on mental health issues. This has become an additional focus later in the pandemic, and is evident in the “Surveys of disease and mental health” in the August literature network graph. These are just some examples of insights that can be gained from comparing network graphs from different time periods.

Figure 1: The research focus in the very early Covid-19 literature

Figure 1 Notes: Red cluster: Health and pandemic management; Green cluster: The disease and its pathophysiology; Blue cluster: Clinical epidemiology of the disease; Yellow cluster: Treatment of the disease.

Figure 2 (below): The research focus in a later stage of the Covid-19 literature

Figure 2 notes: Red cluster: Pandemic of viral pneumonia; public health and world spread; Green cluster: Treatment of COVID-19; Blue cluster: Epidemiology of the pandemic and disease; Yellow cluster: Surveys of disease and mental health; Purple cluster: Lab-work and diagnostics.

Tables of most central keywords in each cluster; in literature published during the early phase of the pandemic, and literature published during August.

The tables below provide an overview of the most central keywords in each cluster in the two time-periods. We extracted more keywords from the second time period as there was substantially more literature published in August alone, than the first 12 weeks of 2020, which the first map is based on. (Centrality measure used is weighted degree centrality)

Table 1: Most frequent keywords in the very early Covid-19 literature

Health and pandemic management (Red)	The disease and its pathophysiology (Yellow)	Clinical epidemiology of the disease (Blue)	Treatment of the disease (Green)
coronavirus infection	pneumonia	female	sars
viral pneumonia	outbreak	adult	animals
betacoronavirus	epidemiology	male	genome, viral
china	antiviral agents	middle aged	phylogeny
disease outbreaks	viruses	aged	zoonosis
travel	republic of korea	young adult	wuhan
pandemic	lopinavir	fever	chiroptera
global health	transmission	tomography, x-ray computed	communicable diseases, emerging
infection control	ritonavir	children	disease reservoirs
public health	mortality	lung	peptidyl-dipeptidase a

Table 2 (below): Most frequent keywords in a later stage of the Covid-19 literature

Pandemic of viral pneumonia; public health and world spread (Red)	Treatment of COVID-19 (Green)	Epidemiology of the pandemic and disease (Blue)	Surveys of disease and mental health (Yellow)	Lab-work and diagnostics (Purple)
pandemic	antiviral agents	female	surveys and questionnaires	clinical laboratory techniques
coronavirus infection	animals	male	cross-sectional studies	rna, viral
viral pneumonia	sars	middle aged	anxiety	real time polymerase chain reaction
betacoronavirus	inflammation	adult	health personnel	antibodies, viral
public health	peptidyl-dipeptidase a	aged	mental health	sensitivity and specificity
united states	spike glycoprotein, coronavirus	young adult	pregnancy	reverse transcriptase polymerase chain reaction
quarantine	epidemiology	adolescent	depression	reproducibility of results
infection control	cytokines	aged, 80 and over	prevalence	immunoglobulin g
italy	hydroxychloroquine	retrospective studies	exercise	diagnosis
telemedicine	viral vaccines	children	stress, psychological	serological test
disease outbreaks	antibodies, monoclonal	china	pregnancy complications, infectious	polymerase chain reaction
communicable disease control	ace2	risk factor	health knowledge, attitudes, practice	seroepidemiologic studies
delivery of health care	interleukin-6	severity of illness index	adaptation, psychological	asymptomatic infections
global health	infection	treatment outcome	risk	immunoglobulin m
personal protective equipment	vaccine	comorbidity	stress	molecular diagnostic techniques
infectious diseases	viruses	hospitalization	nurses	asymptomatic diseases
health policy	cytokine release syndrome	child, preschool	attitude of health personnel	specimen handling
social isolation	host-pathogen interactions	tomography, x-ray computed	health behavior	family characteristics
united kingdom	protein binding	infant	fear	olfaction disorders
practice guidelines as topic	molecular docking simulation	risk assessment	students	nasopharynx

To open the maps directly in VOSviewer, please use the relevant MAP and NET files (Co-occurrence files from March 23rd and the files for August2020Total, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to September 21st, 2020.

by Ingunn Olea Lund | Sep 21, 2020 | CoOccurrence

Corpus downloaded from PubMed September 21st include 52105 publications. There were 3258 keywords that occurred in five or more manuscripts. The keywords divided into five main clusters. To create the map, we used the LinLog method. The minimum cluster size was set to 30.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
public health	pneumonia	pandemic	sars	female
telemedicine	mortality	coronavirus infection	animals	male
epidemiology	hydroxychloroquine	viral pneumonia	antiviral agents	middle aged
mental health	inflammation	betacoronavirus	viruses	adult
epidemic	ace2	china	zoonosis	aged
personal protective equipment	infection	disease outbreaks	mers	children
anxiety	cytokines	infection control	peptidyl-dipeptidase a	clinical laboratory techniques
infectious diseases	acute respiratory distress syndrome	quarantine	spike glycoprotein, coronavirus	young adult
outbreak	chloroquine	united states	vaccine	adolescent
depression	treatment	global health	antibodies, viral	risk factor
health policy	critical illness	italy	respiratory infections	retrospective studies
social distancing	cardiovascular diseases	travel	diagnosis	tomography, x-ray computed
prevention	hypertension	surveys and questionnaires	viral vaccines	aged, 80 and over
transmission	cytokine storm	health personnel	genome, viral	lung
india	ards	time factors	clinical trials as topic	infant
social media	diabetes mellitus	risk assessment	phylogeny	comorbidity
stress	stroke	critical care	chiroptera	fever
lockdown	remdesivir	practice guidelines as topic	wuhan	treatment outcome
cancer	obesity	contact tracing	antibodies, monoclonal	child, preschool
healthcare workers	thrombosis	world health organization	receptors, virus	severity of illness index
triage	angiotensin-converting enzyme inhibitors	delivery of health care	antibody	pregnancy
risk	lopinavir	brazil	immunization, passive	hospitalization
safety	tocilizumab	united kingdom	alanine	prognosis
surgery	diabetes	incidence	drug repositioning	intensive care units
virology	randomised controlled trial	communicable disease control	host-pathogen interactions	real time polymerase chain reaction
knowledge	acute kidney injury	infectious disease transmission, patient-to-professional	adenosine monophosphate	cough
ethics	influenza	republic of korea	virus replication	cross-sectional studies
education	interleukin-6	communication	virus internalization	respiration, artificial
disinfection	ritonavir	stress, psychological	serology	age factors
guidelines	meta-analysis	masks	molecular docking simulation	rna, viral

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph of the current focus of the COVID-19 literature

by Ingunn Olea Lund | Sep 14, 2020 | CoOccurrence

In this week’s update, we are presenting something slightly different; the current focus of the COVID-19 literature, based on publications registered in PubMed as published during week 35-37 (August 24th-September 13th). This resulted in 8144 publications. There were 687 keywords that occurred in five or more manuscripts. These divided into four main clusters. To create the map, we used the LinLog method. The minimum cluster size was set to 15.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4
public health	treatment outcome	pandemic	male
mental health	antiviral agents	coronavirus infection	female
telemedicine	pneumonia	viral pneumonia	middle aged
anxiety	time factors	betacoronavirus	adult
epidemiology	sars	brazil	aged
covid‐19	mortality	clinical laboratory techniques	china
depression	hydroxychloroquine	personal protective equipment	risk factor
infectious diseases	respiration, artificial	united states	adolescent
epidemic	inflammation	health personnel	young adult
quarantine	host microbial interactions	pregnancy	children
lockdown	ace2	infection control	retrospective studies
stress	cytokines	lung	aged, 80 and over
global health	infection	nephrology	severity of illness index
prevalence	randomized controlled trials as topic	australia	cross-sectional studies
india	stroke	masks	surveys and questionnaires

To open the map directly in VOSviewer, please use the “KeywordCoOccurrance5Inst1Resol1_20200914FocusAug24thToSep13th” MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to September 7th, 2020.

by Ingunn Olea Lund | Sep 7, 2020 | CoOccurrence

Corpus downloaded from PubMed September 7th 48067 publications. There were 2960 keywords that occurred in five or more manuscripts. The keywords divided into five main clusters. To create the map, we used the LinLog method. The minimum cluster size was set to 30.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
public health	pneumonia	pandemic	sars	female
epidemiology	mortality	coronavirus infection	animals	male
telemedicine	hydroxychloroquine	viral pneumonia	antiviral agents	middle aged
epidemic	inflammation	betacoronavirus	viruses	adult
mental health	infection	china	zoonosis	aged
personal protective equipment	ace2	disease outbreaks	mers	clinical laboratory techniques
anxiety	acute respiratory distress syndrome	infection control	peptidyl-dipeptidase a	children
infectious diseases	chloroquine	quarantine	spike glycoprotein, coronavirus	young adult
outbreak	cytokines	united states	antibodies, viral	adolescent
depression	vaccine	global health	diagnosis	risk factor
health policy	treatment	italy	respiratory infections	tomography, x-ray computed
social distancing	hypertension	travel	viral vaccines	retrospective studies
prevention	cardiovascular diseases	health personnel	genome, viral	aged, 80 and over
communication	critical illness	surveys and questionnaires	clinical trials as topic	lung
transmission	cytokine storm	time factors	phylogeny	infant
social media	ards	critical care	chiroptera	fever
internet	diabetes mellitus	risk assessment	wuhan	child, preschool
lockdown	stroke	practice guidelines as topic	receptors, virus	comorbidity
cancer	remdesivir	world health organization	antibodies, monoclonal	treatment outcome
stress	obesity	contact tracing	immunization, passive	severity of illness index
triage	lopinavir	delivery of health care	antibody	pregnancy
risk	tocilizumab	infectious disease transmission, patient-to-professional	alanine	hospitalization
healthcare workers	angiotensin-converting enzyme inhibitors	united kingdom	drug repositioning	intensive care units
safety	thrombosis	brazil	adenosine monophosphate	cough
surgery	ct	communicable disease control	pathogenesis	real time polymerase chain reaction
spain	computed tomography	stress, psychological	virus replication	prognosis
education	diabetes	masks	communicable diseases, emerging	incidence
ethics	ritonavir	republic of korea	spike protein	age factors
virology	interleukin-6	forecasting	virus internalization	cross-sectional studies
knowledge	influenza	civil defense	serology	respiration, artificial

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to August 31st, 2020.

by Ingunn Olea Lund | Aug 31, 2020 | CoOccurrence

Corpus downloaded from PubMed August 31st 46037 publications. There were 2833 keywords that occurred in five or more manuscripts. The keywords divided into five main clusters. To create the map, we used the LinLog method. The minimum cluster size was set to 30.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
public health	pneumonia	pandemic	sars	female
epidemiology	mortality	coronavirus infection	animals	male
telemedicine	hydroxychloroquine	viral pneumonia	antiviral agents	middle aged
epidemic	inflammation	betacoronavirus	viruses	adult
mental health	ace2	china	zoonosis	aged
personal protective equipment	infection	disease outbreaks	mers	clinical laboratory techniques
infectious diseases	acute respiratory distress syndrome	infection control	peptidyl-dipeptidase a	children
anxiety	chloroquine	quarantine	spike glycoprotein, coronavirus	young adult
outbreak	cytokines	united states	respiratory infections	adolescent
depression	vaccine	global health	antibodies, viral	risk factor
health policy	treatment	travel	diagnosis	tomography, x-ray computed
social distancing	hypertension	italy	genome, viral	retrospective studies
prevention	cardiovascular diseases	health personnel	viral vaccines	aged, 80 and over
communication	critical illness	intensive care units	transmission	lung
social media	cytokine storm	time factors	phylogeny	infant
masks	ards	critical care	chiroptera	fever
internet	diabetes mellitus	risk assessment	wuhan	child, preschool
triage	stroke	practice guidelines as topic	receptors, virus	comorbidity
healthcare workers	lopinavir	world health organization	immunization, passive	pregnancy
lockdown	obesity	contact tracing	antibodies, monoclonal	severity of illness index
cancer	remdesivir	incidence	drug repositioning	hospitalization
risk	tocilizumab	infectious disease transmission, patient-to-professional	antibody	treatment outcome
stress	angiotensin-converting enzyme inhibitors	delivery of health care	alanine	cough
safety	thrombosis	united kingdom	virus replication	real time polymerase chain reaction
surgery	computed tomography	communicable disease control	adenosine monophosphate	surveys and questionnaires
social isolation	diabetes	clinical trials as topic	communicable diseases, emerging	prognosis
spain	influenza	stress, psychological	virus internalization	age factors
ethics	interleukin-6	republic of korea	disease reservoirs	respiration, artificial
virology	ritonavir	civil defense	models, molecular	rna, viral
education	ct	forecasting	serology	cross-sectional studies

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to August 24th, 2020.

by Ingunn Olea Lund | Aug 30, 2020 | CoOccurrence

Corpus downloaded from PubMed August 24th 41913 publications. There were 2516 keywords that occurred in five or more manuscripts. The keywords divided into five main clusters. To create the map, we used the LinLog method. The minimum cluster size was set to 30.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pneumonia	telemedicine	pandemic	sars	female
epidemiology	mental health	coronavirus infection	animals	male
mortality	personal protective equipment	viral pneumonia	antiviral agents	adult
hydroxychloroquine	anxiety	betacoronavirus	viruses	middle aged
infectious diseases	depression	china	zoonosis	aged
infection	social distancing	disease outbreaks	outbreak	clinical laboratory techniques
inflammation	prevention	public health	mers	children
ace2	masks	infection control	peptidyl-dipeptidase a	young adult
chloroquine	healthcare workers	quarantine	spike glycoprotein, coronavirus	adolescent
acute respiratory distress syndrome	triage	united states	vaccine	tomography, x-ray computed
cytokines	cancer	epidemic	antibodies, viral	risk factor
treatment	safety	global health	respiratory infections	retrospective studies
critical illness	spain	travel	genome, viral	lung
hypertension	surgery	italy	viral vaccines	aged, 80 and over
cardiovascular diseases	stress	health personnel	diagnosis	infant
cytokine storm	lockdown	intensive care units	clinical trials as topic	fever
ards	education	time factors	transmission	child, preschool
diabetes mellitus	knowledge	health policy	phylogeny	comorbidity
stroke	ethics	critical care	chiroptera	pregnancy
obesity	guidelines	practice guidelines as topic	wuhan	hospitalization
remdesivir	patient care	risk assessment	lopinavir	cough
angiotensin-converting enzyme inhibitors	nurses	contact tracing	receptors, virus	severity of illness index
tocilizumab	psychiatry	world health organization	ritonavir	treatment outcome
computed tomography	disinfection	infectious disease transmission, patient-to-professional	antibodies, monoclonal	real time polymerase chain reaction
diabetes	aerosols	delivery of health care	immunization, passive	surveys and questionnaires

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to August 17th, 2020.

by Ingunn Olea Lund | Aug 22, 2020 | CoOccurrence

Corpus downloaded from PubMed August 17th 39914 publications. There were 2395 keywords that occurred in five or more manuscripts; this is the same number as last week. However, the order of the most frequently occurring keywords has changed slightly. The keywords divided into five main clusters. To create the map, we used the LinLog method. The minimum cluster size was set to 30.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
public health	pneumonia	pandemic	sars	male
epidemiology	hydroxychloroquine	coronavirus infection	animals	female
telemedicine	mortality	viral pneumonia	antiviral agents	adult
epidemic	infection	betacoronavirus	viruses	middle aged
personal protective equipment	inflammation	china	zoonosis	aged
mental health	ace2	disease outbreaks	mers	clinical laboratory techniques
infectious diseases	chloroquine	infection control	peptidyl-dipeptidase a	children
outbreak	acute respiratory distress syndrome	quarantine	spike glycoprotein, coronavirus	young adult
anxiety	cytokines	united states	genome, viral	adolescent
health policy	treatment	travel	respiratory infections	tomography, x-ray computed
depression	vaccine	global health	antibodies, viral	risk factor
social distancing	cardiovascular diseases	italy	viral vaccines	retrospective studies
communication	hypertension	health personnel	diagnosis	lung
prevention	critical illness	intensive care units	phylogeny	aged, 80 and over
transmission	cytokine storm	critical care	chiroptera	infant
social media	diabetes mellitus	practice guidelines as topic	wuhan	fever
internet	ards	time factors	receptors, virus	child, preschool
healthcare workers	lopinavir	risk assessment	immunization, passive	comorbidity
triage	angiotensin-converting enzyme inhibitors	contact tracing	antibodies, monoclonal	pregnancy
masks	remdesivir	world health organization	drug repositioning	cough
risk	obesity	united kingdom	alanine	hospitalization
cancer	tocilizumab	infectious disease transmission, patient-to-professional	antibody	severity of illness index
surgery	ritonavir	delivery of health care	adenosine monophosphate	real time polymerase chain reaction
safety	diabetes	communicable disease control	communicable diseases, emerging	surveys and questionnaires
spain	thrombosis	clinical trials as topic	virus replication	prognosis

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to August 10th, 2020.

by Ingunn Olea Lund | Aug 10, 2020 | CoOccurrence

Corpus downloaded from PubMed August 10th 38271 publications. There were 2395 keywords that occurred in five or more manuscripts. These divided into five main clusters. To create the map, we used the LinLog method. The minimum cluster size was set to 30.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pneumonia	telemedicine	pandemic	sars	male
epidemiology	personal protective equipment	coronavirus infection	animals	female
hydroxychloroquine	mental health	viral pneumonia	antiviral agents	adult
infectious diseases	outbreak	betacoronavirus	viruses	middle aged
mortality	anxiety	china	zoonosis	aged
infection	depression	disease outbreaks	mers	clinical laboratory techniques
inflammation	social distancing	public health	peptidyl-dipeptidase a	children
ace2	prevention	infection control	spike glycoprotein, coronavirus	young adult
chloroquine	healthcare workers	quarantine	genome, viral	adolescent
acute respiratory distress syndrome	triage	epidemic	respiratory infections	tomography, x-ray computed
cytokines	masks	united states	vaccine	risk factor
treatment	cancer	travel	antibodies, viral	retrospective studies
cardiovascular diseases	surgery	global health	viral vaccines	lung
hypertension	safety	italy	diagnosis	aged, 80 and over
critical illness	spain	health personnel	clinical trials as topic	infant
cytokine storm	stress	intensive care units	transmission	fever
diabetes mellitus	lockdown	critical care	phylogeny	child, preschool
ards	education	practice guidelines as topic	chiroptera	comorbidity
lopinavir	guidelines	health policy	wuhan	pregnancy
angiotensin-converting enzyme inhibitors	knowledge	time factors	receptors, virus	cough
remdesivir	ethics	risk assessment	immunization, passive	hospitalization
obesity	patient care	contact tracing	antibodies, monoclonal	severity of illness index
tocilizumab	psychiatry	world health organization	drug repositioning	real time polymerase chain reaction
ritonavir	disinfection	united kingdom	alanine	surveys and questionnaires
diabetes	aerosols	infectious disease transmission, patient-to-professional	antibody	prognosis

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to August 3rd, 2020.

by Ingunn Olea Lund | Aug 4, 2020 | CoOccurrence

Corpus downloaded from PubMed August 3rd 36201 publications. There were 2262 keywords that occurred in five or more manuscripts. These divided into five main clusters. To create the map, we used the LinLog method. The minimum cluster size was set to 25.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pneumonia	telemedicine	pandemic	sars	male
epidemiology	personal protective equipment	coronavirus infection	animals	female
hydroxychloroquine	mental health	viral pneumonia	antiviral agents	adult
infectious diseases	anxiety	betacoronavirus	viruses	middle aged
mortality	depression	china	zoonosis	aged
infection	social distancing	disease outbreaks	outbreak	clinical laboratory techniques
inflammation	prevention	public health	peptidyl-dipeptidase a	young adult
ace2	triage	infection control	mers	children
chloroquine	masks	quarantine	spike glycoprotein, coronavirus	adolescent
acute respiratory distress syndrome	healthcare workers	epidemic	genome, viral	tomography, x-ray computed
cytokines	cancer	united states	antibodies, viral	risk factor
vaccine	safety	travel	respiratory infections	retrospective studies
treatment	surgery	global health	viral vaccines	lung
cardiovascular diseases	stress	italy	clinical trials as topic	aged, 80 and over
hypertension	lockdown	health personnel	phylogeny	infant
critical illness	knowledge	intensive care units	transmission	fever
diagnosis	guidelines	practice guidelines as topic	chiroptera	child, preschool
cytokine storm	education	critical care	wuhan	comorbidity
diabetes mellitus	ethics	time factors	receptors, virus	cough
ards	patient care	health policy	immunization, passive	pregnancy
lopinavir	disinfection	risk assessment	antibodies, monoclonal	hospitalization
angiotensin-converting enzyme inhibitors	psychiatry	world health organization	drug repositioning	severity of illness index
remdesivir	aerosols	contact tracing	alanine	real time polymerase chain reaction
obesity	palliative care	united kingdom	adenosine monophosphate	surveys and questionnaires
tocilizumab	fear	infectious disease transmission, patient-to-professional	antibody	treatment outcome

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to July 27th, 2020.

by Ingunn Olea Lund | Jul 28, 2020 | CoOccurrence

Corpus downloaded from PubMed July 27th: 33970 publications. There were 2111 keywords that occurred in five or more manuscripts. These divided into five main clusters. To create the map, we used the LinLog method.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pneumonia	epidemiology	pandemic	sars	male
hydroxychloroquine	telemedicine	coronavirus infection	animals	female
mortality	personal protective equipment	viral pneumonia	antiviral agents	adult
infection	outbreak	betacoronavirus	zoonosis	middle aged
ace2	mental health	china	viruses	aged
inflammation	infectious diseases	disease outbreaks	peptidyl-dipeptidase a	clinical laboratory techniques
chloroquine	anxiety	public health	mers	children
acute respiratory distress syndrome	depression	infection control	spike glycoprotein, coronavirus	young adult
cytokines	social distancing	quarantine	genome, viral	adolescent
treatment	prevention	epidemic	antibodies, viral	tomography, x-ray computed
cardiovascular diseases	transmission	united states	viral vaccines	risk factor
critical illness	masks	travel	vaccine	retrospective studies
diagnosis	triage	global health	respiratory infections	lung
hypertension	healthcare workers	italy	clinical trials as topic	aged, 80 and over
cytokine storm	cancer	health personnel	phylogeny	infant
diabetes mellitus	safety	intensive care units	chiroptera	fever
ards	surgery	practice guidelines as topic	wuhan	child, preschool
lopinavir	stress	critical care	receptors, virus	comorbidity
angiotensin-converting enzyme inhibitors	virology	time factors	immunization, passive	cough
remdesivir	guidelines	health policy	antibodies, monoclonal	pregnancy
obesity	disease	risk assessment	drug repositioning	hospitalization
ritonavir	knowledge	world health organization	alanine	severity of illness index
tocilizumab	lockdown	contact tracing	adenosine monophosphate	real time polymerase chain reaction
computed tomography	education	united kingdom	communicable diseases, emerging	surveys and questionnaires
novel coronavirus pneumonia	patient care	infectious disease transmission, patient-to-professional	models, molecular	prognosis

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph of the current focus of the COVID-19 literature

by Ingunn Olea Lund | Jul 23, 2020 | CoOccurrence

In this week’s update, we are presenting something slightly different; the current focus of the COVID-19 literature, based on publications registered in PubMed as published in the past 3 weeks (21 days). This resulted in 6001 publications. There were 677 keywords that occurred in five or more manuscripts. These divided into five main clusters. To create the map, we used the LinLog method. The minimum cluster size was set to 15.

Cluster 1 (red) covers literature focusing on Public health strategies, treatment, and the global impact of COVID-19.
Cluster 2 (green) includes literature on the role of existing drugs and vaccines in the current pandemic.
Cluster 3 (blue) focuses on demographics and risk factors.
Cluster 4 (yellow) covers literature concentrated on understanding the nature of the virus.
Cluster 5 (Purple) addresses the association between COVID-19 and mental health.

We find it interesting that there does not seem to be a big shift in publication focus from earlier in the pandemic; however, expect this to change as more time has elapsed, allowing for other types of studies to mature and be ready for publication, especially on topics relating to social consequences of the pandemic.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pandemic	sars	female	clinical laboratory techniques	surveys and questionnaires
coronavirus infection	antiviral agents	male	rna, viral	anxiety
viral pneumonia	animals	middle aged	real time polymerase chain reaction	prevalence
betacoronavirus	antibodies, viral	adult	viruses	mental health
italy	hydroxychloroquine	aged	pneumonia	cross-sectional studies
united states	cytokines	china	sensitivity and specificity	depression
telemedicine	inflammation	risk factor	reverse transcriptase polymerase chain reaction	stress, psychological
quarantine	peptidyl-dipeptidase a	young adult	epidemiology	cancer
public health	viral vaccines	retrospective studies	zoonosis	health knowledge, attitudes, practice
personal protective equipment	spike glycoprotein, coronavirus	aged, 80 and over	nasopharynx	fear
disease outbreaks	cytokine release syndrome	adolescent	infection	social media
infection control	thrombosis	children	immunoglobulin g	family
pregnancy	cardiovascular diseases	treatment outcome	respiratory infections	olfaction disorders
health personnel	vaccine	severity of illness index	outbreak	students
spain	renin-angiotensin system	lung	transmission	adaptation, psychological
cities	influenza, human	hospitalization	serological test	communication
incidence	mice	time factors	patient selection	stress
air pollution	angiotensin-converting enzyme inhibitors	prognosis	viral load	emotions
practice guidelines as topic	chloroquine	tomography, x-ray computed	immunoglobulin m	smell
global health	immunologic factors	risk assessment	diagnosis, differential	ageusia

To open the map directly in VOSviewer, please use the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to July 13th, 2020.

by Ingunn Olea Lund | Jul 13, 2020 | CoOccurrence

Corpus downloaded from PubMed July 13th: 30116 publications. There were 1835 keywords that occurred in five or more manuscripts. These divided into five main clusters. To create the map, we used the LinLog method. The minimum cluster size was set to 25.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pneumonia	telemedicine	coronavirus infection	sars	female
epidemiology	personal protective equipment	viral pneumonia	animals	male
hydroxychloroquine	mental health	pandemic	antiviral agents	adult
infectious diseases	anxiety	betacoronavirus	zoonosis	middle aged
infection	surveys and questionnaires	china	outbreak	aged
mortality	depression	disease outbreaks	viruses	clinical laboratory techniques
ace2	social distancing	public health	mers	children
chloroquine	prevention	infection control	peptidyl-dipeptidase a	young adult
inflammation	cross-sectional studies	quarantine	spike glycoprotein, coronavirus	tomography, x-ray computed
cytokines	stress, psychological	epidemic	genome, viral	adolescent
acute respiratory distress syndrome	healthcare workers	travel	viral vaccines	risk factor
treatment	triage	global health	antibodies, viral	retrospective studies
cardiovascular diseases	masks	united states	respiratory infections	lung
critical illness	surgery	italy	vaccine	aged, 80 and over
diagnosis	safety	health personnel	clinical trials as topic	fever
hypertension	guidelines	intensive care units	phylogeny	infant
cytokine storm	knowledge	critical care	chiroptera	child, preschool
diabetes mellitus	cancer	time factors	transmission	cough
ards	stress	practice guidelines as topic	wuhan	real time polymerase chain reaction
lopinavir	ethics	world health organization	receptors, virus	comorbidity
angiotensin-converting enzyme inhibitors	mental health services	health policy	immunization, passive	pregnancy
remdesivir	lockdown	contact tracing	medicine, chinese traditional	hospitalization
ritonavir	education	united kingdom	antibodies, monoclonal	severity of illness index
tocilizumab	disinfection	infectious disease transmission, patient-to-professional	alanine	prognosis
novel coronavirus pneumonia	patient care	risk assessment	adenosine monophosphate	age factors

Cluster description in progress

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to July 6th, 2020.

by Njal | Jul 7, 2020 | CoOccurrence

Corpus downloaded from PubMed July 6th: 28256 publications. There were 1732 keywords that occurred in five or more manuscripts. These divided into five main clusters. To create the map, we used the LinLog method.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pneumonia	coronavirus infection	sars	female	mental health
epidemiology	viral pneumonia	animals	male	anxiety
outbreak	pandemic	antiviral agents	adult	depression
telemedicine	betacoronavirus	zoonosis	middle aged	fear
viruses	china	peptidyl-dipeptidase a	aged	stress
infection	disease outbreaks	hydroxychloroquine	clinical laboratory techniques	social support
infectious diseases	public health	spike glycoprotein, coronavirus	young adult	emotions
mortality	infection control	genome, viral	children	psychological distress
inflammation	quarantine	chloroquine	tomography, x-ray computed	medical staff
cardiovascular diseases	epidemic	viral vaccines	adolescent	anxiety disorders
treatment	travel	antibodies, viral	retrospective studies	health status
respiratory infections	global health	ace2	lung	quality of life
transmission	italy	phylogeny	risk factor	sleep
prevention	united states	clinical trials as topic	fever	asian continental ancestry group
hypertension	personal protective equipment	chiroptera	aged, 80 and over	follow-up studies
diagnosis	health personnel	middle east respiratory syndrome coronavirus	infant	resilience, psychological
angiotensin-converting enzyme inhibitors	time factors	mers	child, preschool	workforce
ards	practice guidelines as topic	cytokines	cough	dementia
diabetes mellitus	critical care	wuhan	comorbidity	suicide
novel coronavirus pneumonia	contact tracing	receptors, virus	pregnancy	ptsd

Cluster description in progress

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to June 29th, 2020.

by Njal | Jun 30, 2020 | CoOccurrence

Corpus downloaded from PubMed June 29th: 26187 publications. There were 1789 keywords that occurred in five or more manuscripts. These divided into five main clusters. To create the map, we used the LinLog method.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pneumonia	coronavirus infection	sars	female	mental health
epidemiology	viral pneumonia	animals	male	anxiety
outbreak	pandemic	antiviral agents	adult	depression
telemedicine	betacoronavirus	zoonosis	middle aged	fear
viruses	china	peptidyl-dipeptidase a	aged	stress
infection	disease outbreaks	hydroxychloroquine	clinical laboratory techniques	social support
infectious diseases	public health	spike glycoprotein, coronavirus	young adult	emotions
mortality	infection control	genome, viral	children	psychological distress
inflammation	quarantine	chloroquine	tomography, x-ray computed	medical staff
cardiovascular diseases	epidemic	viral vaccines	adolescent	anxiety disorders
treatment	travel	antibodies, viral	retrospective studies	health status
respiratory infections	global health	ace2	lung	quality of life
transmission	italy	phylogeny	risk factor	sleep
prevention	united states	clinical trials as topic	fever	asian continental ancestry group
hypertension	personal protective equipment	chiroptera	aged, 80 and over	follow-up studies
diagnosis	health personnel	middle east respiratory syndrome coronavirus	infant	resilience, psychological
angiotensin-converting enzyme inhibitors	time factors	mers	child, preschool	workforce
ards	practice guidelines as topic	cytokines	cough	dementia
diabetes mellitus	critical care	wuhan	comorbidity	suicide
novel coronavirus pneumonia	contact tracing	receptors, virus	pregnancy	ptsd

Cluster description in progress

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to June 22nd, 2020.

by Njal | Jun 27, 2020 | CoOccurrence

Corpus downloaded from PubMed June 22nd: 24167 publications. There were 1656 keywords that occurred in five or more manuscripts. These divided into five main clusters. To create the map, we used the LinLog method.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pneumonia	coronavirus infection	sars	female	mental health
epidemiology	viral pneumonia	animals	male	anxiety
outbreak	pandemic	antiviral agents	adult	depression
telemedicine	betacoronavirus	zoonosis	middle aged	fear
viruses	china	peptidyl-dipeptidase a	aged	stress
infection	disease outbreaks	hydroxychloroquine	clinical laboratory techniques	social support
infectious diseases	public health	spike glycoprotein, coronavirus	young adult	emotions
mortality	infection control	genome, viral	children	psychological distress
inflammation	quarantine	chloroquine	tomography, x-ray computed	medical staff
cardiovascular diseases	epidemic	viral vaccines	adolescent	anxiety disorders
treatment	travel	antibodies, viral	retrospective studies	health status
respiratory infections	global health	ace2	lung	quality of life
transmission	italy	phylogeny	risk factor	sleep
prevention	united states	clinical trials as topic	fever	asian continental ancestry group
hypertension	personal protective equipment	chiroptera	aged, 80 and over	follow-up studies
diagnosis	health personnel	middle east respiratory syndrome coronavirus	infant	resilience, psychological
angiotensin-converting enzyme inhibitors	time factors	mers	child, preschool	workforce
ards	practice guidelines as topic	cytokines	cough	dementia
diabetes mellitus	critical care	wuhan	comorbidity	suicide
novel coronavirus pneumonia	contact tracing	receptors, virus	pregnancy	ptsd

Cluster description in progress

To open the map directly in VOSviewer, please use these the latest MAP and NET files, available through the Open Science Foundation (OSF) repository:
https://osf.io/54gqw/

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to June 15th, 2020.

by Ingunn Olea Lund | Jun 16, 2020 | CoOccurrence

Corpus downloaded from PubMed June 15th: 22147 publications. There were 1535 keywords that occurred in five or more manuscripts. These divided into five main clusters. To create the map, we used the LinLog method.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pneumonia	coronavirus infection	sars	female	mental health
epidemiology	viral pneumonia	animals	male	anxiety
outbreak	pandemic	antiviral agents	adult	depression
telemedicine	betacoronavirus	zoonosis	middle aged	fear
viruses	china	peptidyl-dipeptidase a	aged	stress
infection	disease outbreaks	hydroxychloroquine	clinical laboratory techniques	social support
infectious diseases	public health	spike glycoprotein, coronavirus	young adult	emotions
mortality	infection control	genome, viral	children	psychological distress
inflammation	quarantine	chloroquine	tomography, x-ray computed	medical staff
cardiovascular diseases	epidemic	viral vaccines	adolescent	anxiety disorders
treatment	travel	antibodies, viral	retrospective studies	health status
respiratory infections	global health	ace2	lung	quality of life
transmission	italy	phylogeny	risk factor	sleep
prevention	united states	clinical trials as topic	fever	asian continental ancestry group
hypertension	personal protective equipment	chiroptera	aged, 80 and over	follow-up studies
diagnosis	health personnel	middle east respiratory syndrome coronavirus	infant	resilience, psychological
angiotensin-converting enzyme inhibitors	time factors	mers	child, preschool	workforce
ards	practice guidelines as topic	cytokines	cough	dementia
diabetes mellitus	critical care	wuhan	comorbidity	suicide
novel coronavirus pneumonia	contact tracing	receptors, virus	pregnancy	ptsd

Cluster description in progress

To open the map directly in VOSviewer, please use these two files.
KeywordCoOccurrance5Inst1Resol1_20200615NETb
KeywordCoOccurrance5Inst1Resol1_20200615MAPb

The maps are created with the following “thesaurus” to clean the data:
Thesaurus20200601

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to June 8th, 2020.

by Ingunn Olea Lund | Jun 8, 2020 | CoOccurrence

Corpus downloaded from PubMed June 8th: 19426 publications. There were 1814 keywords that occurred in four or more manuscripts. These divided into five main clusters. To create the map, we used the LinLog method.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pneumonia	coronavirus infection	sars	female	mental health
epidemiology	viral pneumonia	animals	male	surveys and questionnaires
outbreak	pandemic	antiviral agents	adult	anxiety
zoonosis	betacoronavirus	peptidyl-dipeptidase a	middle aged	depression
viruses	china	hydroxychloroquine	aged	cross-sectional studies
telemedicine	disease outbreaks	spike glycoprotein, coronavirus	clinical laboratory techniques	knowledge
infection	public health	genome, viral	children	fear
infectious diseases	infection control	chloroquine	young adult	stress
mortality	quarantine	viral vaccines	tomography, x-ray computed	social support
treatment	travel	antibodies, viral	adolescent	emotions
wuhan	epidemic	phylogeny	lung	medical staff
respiratory infections	global health	ace2	retrospective studies	psychological distress
transmission	italy	clinical trials as topic	risk factor	nursing homes
prevention	united states	chiroptera	fever	anxiety disorders
diagnosis	personal protective equipment	inflammation	aged, 80 and over	health status
novel coronavirus pneumonia	health personnel	cardiovascular diseases	infant	quality of life
safety	time factors	middle east respiratory syndrome coronavirus	cough	asian continental ancestry group
telehealth	practice guidelines as topic	mers	child, preschool	sleep
influenza	critical care	cytokines	comorbidity	pharmacists
virology	contact tracing	receptors, virus	pregnancy	resilience, psychological

Cluster description in progress

To open the map directly in VOSviewer, please use these two files.
KeywordCoOccurrance4Inst1Resol1_20200608NET
KeywordCoOccurrance4Inst1Resol1_20200608MAP

The maps are created with the following “thesaurus” to clean the data:
Thesaurus20200601

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to June 1st, 2020.

by Ingunn Olea Lund | Jun 1, 2020 | CoOccurrence

Corpus downloaded from PubMed 1st June: 17346 publications. There were 1648 keywords that occurred in four or more manuscripts. These divided into five main clusters.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality/total link strength)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pneumonia	coronavirus infection	sars	female	mental health
epidemiology	viral pneumonia	animals	male	anxiety
outbreak	pandemic	antiviral agents	adult	depression
zoonosis	betacoronavirus	peptidyl-dipeptidase a	middle aged	fear
viruses	china	spike glycoprotein, coronavirus	clinical laboratory techniques	social support
telemedicine	disease outbreaks	hydroxychloroquine	aged	stress
infection	public health	genome, viral	young adult	emotions
infectious diseases	infection control	chloroquine	children	medical staff
mortality	travel	viral vaccines	tomography, x-ray computed	psychological distress
treatment	quarantine	antibodies, viral	adolescent	anxiety disorders
wuhan	epidemic	phylogeny	lung	health status
respiratory infections	global health	clinical trials as topic	retrospective studies	lockdown
transmission	italy	chiroptera	risk factor	sleep
prevention	united states	ace2	fever	quality of life
diagnosis	personal protective equipment	cardiovascular diseases	infant	resilience, psychological
novel coronavirus pneumonia	health personnel	middle east respiratory syndrome coronavirus	aged, 80 and over	follow-up studies
ards	time factors	inflammation	cough	workforce
safety	practice guidelines as topic	mers	child, preschool	self care
acute respiratory distress syndrome	critical care	receptors, virus	comorbidity	suicide
influenza	contact tracing	cytokines	pregnancy	ptsd

Cluster description in progress

To open the map directly in VOSviewer, please use these two files.
CoOccurrance4Inst1Resol1_20200601MAP
CoOccurrance4Inst1Resol1_20200601NET

The maps are created with the following “thesaurus” to clean the data:
Thesaurus20200601

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to May 25th, 2020.

by Ingunn Olea Lund | May 25, 2020 | CoOccurrence

Corpus downloaded from PubMed 25th May: 15438 publications. There were 1515 keywords that occurred in four or more manuscripts. These divided into five main clusters.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
pneumonia	coronavirus infection	sars	female	anxiety
epidemiology	viral pneumonia	animals	male	depression
outbreak	pandemic	antiviral agents	adult	fear
zoonosis	betacoronavirus	peptidyl-dipeptidase a	middle aged	social support
viruses	china	spike glycoprotein, coronavirus	clinical laboratory techniques	medical staff
infection	disease outbreaks	hydroxychloroquine	aged	psychological distress
infectious diseases	public health	genome, viral	young adult	anxiety disorders
mortality	infection control	chloroquine	tomography, x-ray computed	stress
wuhan	travel	viral vaccines	children	sleep
treatment	quarantine	antibodies, viral	adolescent	quality of life
respiratory infections	epidemic	phylogeny	lung	resilience, psychological
transmission	global health	clinical trials as topic	retrospective studies	workforce
diagnosis	italy	chiroptera	risk factor	self care
prevention	united states	ace2	fever	suicide
novel coronavirus pneumonia	personal protective equipment	cardiovascular diseases	infant	public health emergencies
ards	health personnel	middle east respiratory syndrome coronavirus	aged, 80 and over	perception
influenza	practice guidelines as topic	inflammation	cough	ptsd
virology	time factors	receptors, virus	child, preschool	crisis management
acute respiratory distress syndrome	telemedicine	mers	comorbidity	mindfulness
guidelines	mental health	lopinavir	pregnancy	adolescents

Cluster description in progress

To open the map directly in VOSviewer, please use these two files.
KeywordCoOccurrance4Inst1Resol20200525MAP
KeywordCoOccurrance4Inst1Resol20200525NET

The maps are created with the following “thesaurus” to clean the data:
KeywordCoOccurrance_20200427_Thesaurus

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to May 18th, 2020.

by Ingunn Olea Lund | May 18, 2020 | CoOccurrence

Corpus downloaded from PubMed 18th May: 13103 publications. There were 1861 keywords that occurred in three or more manuscripts. These divided into four main clusters.

This week’s rapport strengthens our observation from last couple of weeks that the clusters and topics seem to vary less, signifying that cluster may be more robust. This is true even if cluster 1 and 2 have changed places. Maybe this switch could imply that research and publication is switching more to how to managing the disease, than mainly be focused on the understanding of the phenomenon. In cluster 3 the term(s) (hydroxyl)chloroquine is rising on the list. Last week there was a fifth cluster that we called “clinical issues”, but the terms included in this cluster have returned to the third cluster where they originated.

Cluster 1 could be called “disease epidemiology” and includes terms like pneumonia, epidemiology, outbreak, infection, infectious diseases, novel coronavirus pneumonia, treatment and transmission. This cluster contains 2 major topics: a) the main term “the disease” which in addition to the above mentioned terms, but also b) “inpatient care” which contains terms like ARDS, critical illness and airway management. In this cluster some smaller topics are also present.

Cluster 2 could be called «global virus pandemic» and includes terms (beta)coronavirus infection, viral pneumonia, pandemic/epidemic, public health, infection control and quarantine. This cluster contains 3 main topics a) “preventive epidemiology”, which in addition to the terms public health and quarantine contains terms like disease outbreak, travel and contact tracing, b) “care management” which includes terms like infection control, practice guidelines and health personnel and c) “vulnerability” that contains terms like mental health, psychological stress and health service accessibility.

Cluster 3 could be called “pathophysiology and origin” and includes terms like SARS, animals, zoonosis, antiviral agents, viral genome, phylogeny and chiroptera. This cluster contains to major topics: a) “viral biology” which in addition to terms like SARS, animals, viral genome and phylogeny includes terms like spike glycoprotein and peptidyl-dipeptidase a and b) “drug treatment” which in addition to the term antiviral agent, (hydroxyl)chloroquine and chiroptera contains terms like traditional Chinese medicine and lopinavir.

Cluster 4 could be named “clinical epidemiology” and contains terms like mortality, age, gender, clinical laboratory techniques and fever. Also in this cluster, there is only this major topic. Smaller topics include “population care”, “serology” and “pregnancy”.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality)

Cluster 1	Cluster 2	Cluster 3	Cluster 4
pneumonia	coronavirus infection	sars	female
epidemiology	viral pneumonia	animals	male
outbreak	pandemic	antiviral agents	adult
viruses	betacoronavirus	peptidyl-dipeptidase a	middle aged
infection	china	zoonosis	clinical laboratory techniques
infectious diseases	disease outbreaks	spike glycoprotein, coronavirus	aged
mortality	public health	genome, viral	young adult
treatment	infection control	hydroxychloroquine	tomography, x-ray computed
critical illness	travel	viral vaccines	children
respiratory infections	quarantine	chloroquine	adolescent
transmission	epidemic	phylogeny	lung
diagnosis	global health	antibodies, viral	risk factor
prevention	united states	chiroptera	retrospective studies
novel coronavirus pneumonia	italy	clinical trials as topic	fever
ards	health personnel	middle east respiratory syndrome coronavirus	aged, 80 and over
virology	personal protective equipment	ace2	infant
influenza	practice guidelines as topic	receptors, virus	cough
guidelines	time factors	wuhan	child, preschool
japan	telemedicine	cardiovascular diseases	comorbidity
therapy	mental health	inflammation	real-time polymerase chain reaction
acute respiratory distress syndrome	contact tracing	mers	severity of illness index
telehealth	world health organization	angiotensin-converting enzyme inhibitors	pregnancy
immunosuppression	united kingdom	immunization, passive	surveys and questionnaires
lymphopenia	infectious disease transmission, patient-to-professional	lopinavir	hospitalization
respiratory tract infections	critical care	hypertension	prognosis

Cluster description in progress

To open the map directly in VOSviewer, please use these two files.

KeywordCoOccurrance3Inst1Resol20200518MAP
KeywordCoOccurrance3Inst1Resol20200518NET

The maps are created with the following “thesaurus” to clean the data:
KeywordCoOccurrance_20200427_Thesaurus

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to May 11th, 2020.

by Njal | May 12, 2020 | CoOccurrence

Corpus downloaded from PubMed 11th May: 11005 publications. There were 1634 keywords that occurred in three or more manuscripts. These divided into four main clusters.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5	Cluster 6
china	infection	sars	coronavirus infection	female	mental health
disease outbreaks	cardiovascular diseases	animals	viral pneumonia	male	surveys and questionnaires
public health	treatment	antiviral agents	betacoronavirus	adult	anxiety
travel	angiotensin-converting enzyme inhibitors	peptidyl-dipeptidase a	pandemic	middle aged	health knowledge, attitudes, practice
epidemic	hypertension	spike glycoprotein, coronavirus	infection control	clinical laboratory techniques	stress, psychological
quarantine	diabetes mellitus	genome, viral	italy	aged	cross-sectional studies
global health	diagnosis	viral vaccines	practice guidelines as topic	tomography, x-ray computed	depression
epidemiology	ards	phylogeny	health personnel	young adult	mental health services
outbreak	angiotensin receptor antagonists	chiroptera	personal protective equipment	children	psychiatry
united states	renin-angiotensin system	rna, viral	infectious disease transmission, patient-to-professional	adolescent	knowledge
zoonosis	influenza	antibodies, viral	united kingdom	lung	mental disorders
time factors	therapy	hydroxychloroquine	critical care	risk factor	fear
viruses	acute respiratory distress syndrome	chloroquine	delivery of health care	retrospective studies	social support
world health organization	guidelines	clinical trials as topic	intensive care units	pneumonia	universities
contact tracing	immunosuppression	middle east respiratory syndrome coronavirus	respiration, artificial	fever	emotions
telemedicine	safety	receptors, virus	influenza, human	aged, 80 and over	social isolation
infectious diseases	diabetes complications	ace2	health resources	cough	medical staff
risk assessment	airway management	mers	critical illness	infant	anxiety disorders
civil defense	heart failure	immunization, passive	decision making	child, preschool	health status
mortality	covid	inflammation	cross infection	comorbidity	students, medical
population surveillance	respiratory failure	cytokines	brazil	real-time polymerase chain reaction	psychological distress
health policy	surgery	lopinavir	neoplasms	severity of illness index	corona
patient isolation	corona virus	antibodies, monoclonal	india	pregnancy	schools
communicable disease control	myocardium	ritonavir	masks	radiography, thoracic	students
wuhan	tracheostomy	alanine	state medicine	prognosis	asian continental ancestry group

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KeywordCoOccurrance_20200511_NET
KeywordCoOccurrance_20200511_MAP

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KeywordCoOccurrance_20200427_Thesaurus

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to May 4th, 2020.

by Njal | May 4, 2020 | CoOccurrence

Corpus downloaded from PubMed 4th May: 8791 publications. There were 1381 keywords that occurred in three or more manuscripts. These divided into five main clusters.

Cluster descriptions

In progress..

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
coronavirus infection	epidemiology	sars	female	mental health
viral pneumonia	outbreak	animals	male	surveys and questionnaires
betacoronavirus	viruses	antiviral agents	adult	health knowledge, attitudes, practice
pandemic	infectious diseases	peptidyl-dipeptidase a	middle aged	cross-sectional studies
china	infection	zoonosis	clinical laboratory techniques	anxiety
disease outbreaks	respiration, artificial	spike glycoprotein, coronavirus	aged	stress, psychological
public health	critical illness	genome, viral	young adult	depression
infection control	treatment	viral vaccines	tomography, x-ray computed	knowledge
travel	respiratory infections	phylogeny	children	fear
epidemic	diagnosis	chiroptera	adolescent	emotions
global health	transmission	clinical trials as topic	risk factor	social support
quarantine	prevention	chloroquine	lung	dentists
united states	respiratory insufficiency	hydroxychloroquine	fever	medical staff
italy	influenza	middle east respiratory syndrome coronavirus	pneumonia	anxiety disorders
time factors	taiwan	antibodies, viral	retrospective studies	social isolation
health personnel	guidelines	wuhan	cough	health status
world health organization	respiratory tract infections	receptors, virus	aged, 80 and over	asian continental ancestry group
practice guidelines as topic	immunosuppression	influenza, human	infant	resilience, psychological
contact tracing	extracorporeal membrane oxygenation	ace2	child, preschool	emerging infectious disease
telemedicine	preparedness	cardiovascular diseases	severity of illness index	sleep
personal protective equipment	hong kong	mers	comorbidity	sleep initiation and maintenance disorders
civil defense	seasons	immunization, passive	real-time polymerase chain reaction	stress
infectious disease transmission, patient-to-professional	airway management	inflammation	radiography, thoracic	family
risk assessment	respiratory therapy	lopinavir	pregnancy	practice
critical care	screening	angiotensin-converting enzyme inhibitors	mortality	quality of life

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KeywordCoOccurrance_20200505_MAP

KeywordCoOccurrance_20200505_NET

The maps are created with the following “thesaurus” to clean the data:
KeywordCoOccurrance_20200427_Thesaurus

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to April 27th, 2020.

by Njal | Apr 28, 2020 | CoOccurrence

Corpus downloaded from PubMed 27th April: 6958 publications. There were 1082 keywords that occurred in three or more manuscripts. These divided into four main clusters.

Cluster descriptions

This week’s rapport confirms what we suspected last week, that the clusters and topics seem to vary less. Clusters 1, 3 and 4 were quite stable, while cluster 2 saw a bit of change, mostly in the addition of a new topic (“inpatient care”). New from this week is that we in cluster 4 mention 3 upcoming topics with increasing number of publications. Finally, the last cluster (cluster 5) seemed to take a bit different course, mostly because most of the terms here moved to be included in cluster 1 in a new topic. Cluster 5 now is more about the disease.

Cluster 1 could be called «global virus pandemic» and includes terms like (beta)coronavirus infection, viral pneumonia, disease outbreak and public health. This cluster contains 3 major topics: a) “preventive epidemiology”, which in addition to the terms like disease outbreak and public health includes terms like travel, epidemic, global heath and civil defence, b) “care management” which includes terms like infection control, practice guidelines and health personnel and c) “vulnerability” that contains terms like mental health, psychological stress and health service accessibility.

Cluster 2 could be called “disease epidemiology” and includes terms like pneumonia, epidemiology, outbreak, infection, infectious diseases, novel coronavirus pneumonia, treatment and transmission. This cluster contains 2 major topics: a) the main term “the disease” which in addition to the above mentioned terms, but also b) “inpatient care” which contains terms like ARDS, critical illness and airway management. In this cluster some smaller topics are also present.

Cluster 3 could be called “pathophysiology and origin” and includes terms like SARS, animals, zoonosis, antiviral agents, viral genome, phylogeny and chiroptera. This cluster contains to major topics: a) “viral biology” which in addition to terms like SARS, animals, viral genome and phylogeny includes terms like spike glycoprotein and peptidyl-dipeptidase a and b) “drug treatment” which in addition to the term antiviral agent and chiroptera contains terms like traditional Chinese medicine, chloroquine and lopinavir.

Cluster 5 could be named “clinical issues” and contains terms like cardiovascular diseases, hypertension, angiotensin-converting enzyme inhibitors and diabetes mellitus. This is the smallest cluster with only one topic.

Table of the most central keywords in each cluster

(Centrality measure used is weighted degree centrality)

Cluster 1	Cluster 2	Cluster 3	Cluster 4	Cluster 5
coronavirus infection	pneumonia	sars	male	cardiovascular diseases
viral pneumonia	epidemiology	animals	female	hypertension
betacoronavirus	outbreak	antiviral agents	adult	angiotensin-converting enzyme inhibitors
pandemic	viruses	zoonosis	middle aged	diabetes mellitus
china	infection	peptidyl-dipeptidase a	clinical laboratory techniques	angiotensin receptor antagonists
disease outbreaks	infectious diseases	spike glycoprotein, coronavirus	aged	renin-angiotensin system
public health	respiratory infections	genome, viral	young adult	diabetes complications
travel	critical illness	phylogeny	tomography, x-ray computed	heart failure
infection control	treatment	chiroptera	children	myocardium
epidemic	novel coronavirus pneumonia	viral vaccines	adolescent	antihypertensive agents
global health	diagnosis	middle east respiratory syndrome coronavirus	fever	diabetes mellitus, type 2
quarantine	transmission	antibodies, viral	risk factor	heart diseases
united states	prevention	wuhan	lung	angiotensin ii
italy	ards	receptors, virus	retrospective studies	myocarditis
practice guidelines as topic	influenza	clinical trials as topic	cough	cardiovascular system

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KeywordCoOccurrance_20200427_MAP
KeywordCoOccurrance_20200427_NET

The maps are created with the following “thesaurus” to clean the data:
KeywordCoOccurrance_20200427_Thesaurus

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to April 20th, 2020.

by Njal | Apr 27, 2020 | CoOccurrence

Corpus downloaded from PubMed 20th April: 5228 publications. There were 853 keywords that occurred in three or more manuscripts. These divided into four main clusters.

Cluster descriptions

Cluster 1 could be called «A global virus pandemic» and includes terms like (beta)coronavirus infection, viral pneumonia, disease outbreak and public health. This cluster contains 2 major topics: a) “preventive epidemiology”, which in addition to the terms like disease outbreak and public health includes terms like travel, global heath and civil defence and b) “care management” which includes terms like infection control, practice guidelines and health personnel

Cluster 2 could be called “disease epidemiology” and includes terms like epidemiology, outbreak, infection, infectious diseases, novel coronavirus pneumonia, treatment and transmission. This is a small cluster with only this major topic

Cluster 3 could be called “pathophysiology and origin” and includes terms like SARS, animals, zoonosis, antiviral agents, viral genome, phylogeny and chiroptera. This cluster contains to major topics: a) “viral biology” which in addition to terms like SARS, animals, viral genome, phylogeny and chiroptera includes terms like spike glycoprotein and peptidyl-dipeptidase a and b) “drug treatment” which in addition to the term antiviral agent contains terms like traditional Chinese medicine, chloroquine and lopinavir

Cluster 4 could be named “clinical epidemiology” and contains terms like mortality, age, gender, clinical laboratory techniques and fever. Also in this cluster, there is only this major topic.

Cluster 5 could be named “related topics” and contains terms like mental health and anxiety and depression one side , but also terms like surveys and questionnaires, cross-sectional studies and health knowledge; attitudes and practice on the other. This is the smallest cluster with only one topic

Table of ten most central keywords in each cluster

(Centrality measure used is weighted degree centrality)

Cluster 1 (Red)	Cluster 2 (Green)	Cluster 3 (Blue)	Cluster 4 (Yellow)	Cluster 5 (Purple)
coronavirus infection	pneumonia	sars	female	mental health
viral pneumonia	epidemiology	animals	male	health knowledge, attitudes, practice
betacoronavirus	outbreak	zoonosis	adult	anxiety
pandemic	infection	antiviral agents	middle aged	depression
china	infectious diseases	genome, viral	aged	fear
disease outbreaks	novel coronavirus pneumonia	phylogeny	clinical laboratory techniques	social support
public health	treatment	chiroptera	young adult	anxiety disorders
travel	transmission	spike glycoprotein, coronavirus	children	emotions
epidemic	prevention	peptidyl-dipeptidase a	adolescent	health status
global health	inflammation	viral vaccines	tomography, x-ray computed	resilience, psychological

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CoOccurrance3Inst1Resol20thApril20NET

CoOccurrance3Inst1Resol20thApril20MAP

The maps are created with the following “thesaurus” to clean the data: Thesaurus13thApril

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to April 13th, 2020.

by Njal | Apr 13, 2020 | CoOccurrence

Corpus downloaded from PubMed 13th April: 3683 publications. There were 607 keywords that occurred in three or more manuscripts. These divided into four main clusters.

Cluster descriptions

Cluster descriptions

Cluster 1 (red) relates to “Health and pandemic management”, and include topics like the epidemic, the impact on global health, the public health, infection control and health personnel. Within this cluster, we found the topic of “Global health politics”, which in addition to terms on the epidemic, the impact on global health and public health included terms like population surveillance, civil defense and risk assessment. Further, within this cluster, we found the topic of “Pandemic management”, which in addition to the terms infection control and health personnel included terms like practice guidelines and patient isolation.

Cluster 2 (green) related to “The disease and its treatment”, including topics like its pneumonia and diagnosis, but also topics like antiviral drugs and artificial respiration. Within this cluster, we found the topic of “Clinical picture”, which in addition to terms on pneumonia and diagnosis, included terms like corona virus and infectious disease. Further, within this cluster, we find the topic of “Drug treatment”, which in addition to the terms antiviral drugs and artificial respiration, includes terms like lopinavir, alanine, chloroquine and clinical trials.

Cluster 3 (blue) related to the “The virus and its epidemiology”, including terms like SARS, it being a zoonosis, its genome and the outbreak in Wuhan. Two major topics were identified within this cluster: “Clinical epidemiology”, which in addition to it being a zoonosis and broke out in Wuhan, includes terms like transmission and basic reproduction rate. The other major topic identified is on the “Virus biology”, which in addition to the terms SARS and genome, included terms like phylogeny, glycoproteins and antibodies.

Cluster 4 (yellow) related to “Clinical epidemiology”, with terms relating to age, gender, and basic clinical signs and procedures (like x-ray, CT, fever).

Table of ten most central keywords in each cluster

(Centrality measure used is weighted degree centrality)

Cluster 1 (Red)	Cluster 2 (Green)	Cluster 3 (Blue)	Cluster 4 (Yellow)
coronavirus infection	pneumonia	sars	male
viral pneumonia	epidemiology	animals	female
betacoronavirus	zoonosis	genome, viral	adult
pandemic	outbreak	antiviral agents	middle aged
china	wuhan	phylogeny	aged
disease outbreaks	viruses	chiroptera	young adult
travel	infection	spike glycoprotein, coronavirus	adolescent
public health	novel coronavirus pneumonia	peptidyl-dipeptidase a	children
infection control	infectious diseases	viral vaccines	tomography, x-ray computed
global health	transmission	antibodies, viral	fever

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CoOccurrance3Inst1Resol13thApril20MAP

CoOccurrance3Inst1Resol13thApril20NET

The maps are created with the following “thesaurus” to clean the data: Thesaurus13thApril

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to April 6th, 2020.

by Njal | Apr 6, 2020 | CoOccurrence

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to April 6th, 2020.

Corpus downloaded from PubMed 6th April: 2684 publications. There were 453 keywords that occurred in three or more manuscripts. These divided into four main clusters.

Cluster descriptions

Cluster descriptions

Cluster 4 (yellow) related to “Clinical epidemiology”, with terms relating to age, gender, and basic clinical signs and procedures (like x-ray, CT, fever).

Table of ten most central keywords in each cluster

(Centrality measure used is weighted degree centrality)

Cluster 1 (Red)	Cluster 2 (Green)	Cluster 3 (Blue)	Cluster 4 (Yellow)
coronavirus infection	pneumonia	sars	female
viral pneumonia	antiviral agents	animals	male
betacoronavirus	viral vaccines	epidemiology	adult
china	pregnancy	genome, viral	middle aged
pandemic	influenza, human	outbreak	aged
disease outbreaks	respiration, artificial	zoonosis	young adult
travel	lopinavir	phylogeny	adolescent
public health	ritonavir	chiroptera	tomography, x-ray computed
epidemic	alanine	wuhan	children
infection control	chloroquine	spike glycoprotein, coronavirus	fever

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CoOccurrance3Inst1Resol_6April20MAP

CoOccurrance3Inst1Resol_6April20NET

The maps are created with the following “thesaurus” to clean the data: Thesaurus6April

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to March 30th, 2020.

by Njal | Mar 30, 2020 | CoOccurrence

Corpus downloaded from PubMed 30th March: 1788 publications. There were 308 keywords that occurred in three or more manuscripts. These divided into four clusters.

Cluster descriptions

Cluster 1 (red) relates to “Health and pandemic management”, and include topics like the pandemic, the impact on global health, the disease outbreak, infection control and travel. Within this cluster, we found the topic of “Global health politics”, which in addition to terms on the pandemic and the impact on global health included terms on countries, public health, disease transmission and health planning. Further, within this cluster, we found the topic of “Pandemic politics”, which in addition to the terms disease outbreak and infection control included terms like mass screening and health personnel.

Cluster 2 (green) related to “The disease and its pathophysiology” of COVID-19, including topics like its genome and its relationship with SARS, but also topics like epidemiology and its outbreak and that it is a zoonosis. Within this cluster, we found the topic of “Viral biology”, which in addition to terms on its genome and SARS, included terms like phylogeny and disease reservoirs. Further, within this cluster, we find the topic of “Viral spread”, which in addition to the term epidemiology, includes terms like quarantine, importation and incubation period. Lastly, this cluster contained the topic “Basic clinical medicine”, which in addition to the terms outbreak and zoonosis, included terms like transmission and mortality.

Cluster 3 (blue) related to the “Clinical epidemiology of the disease”, including topics like age (aged, children, adolescent) and gender (male and female), risk factor, population surveillance and pregnancy. Only one major topic was identified within this cluster: “Clinical characteristics”. In addition to the terms on age and gender, this topic included terms like prognosis, myalgia, biomarkers and laboratory medicine.

Cluster 4 (yellow) related to “Treatment of the disease”, with terms like antiviral agents, diagnosis, ritonavir and drug combinations.

Table of ten most central keywords in each cluster

(Centrality measure used is weighted degree centrality)

Cluster 1 (Red)	Cluster 2 (Green)	Cluster 3 (lBlue)	Cluster 4 (Yellow)
disease outbreaks	sars	female	pneumonia
travel	animals	male	antiviral agents
pandemic	epidemiology	adult	lopinavir
public health	genome, viral	middle aged	respiration, artificial
epidemic	phylogeny	aged	ritonavir
global health	outbreak	young adult	diagnosis, differential
infection control	zoonosis	children	influenza, human
population surveillance	wuhan	tomography, x-ray computed	novel coronavirus pneumonia
united states	chiroptera	fever	alanine
risk assessment	communicable diseases, emerging	adolescent	diagnosis

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CoOccurrance3Inst1Resol30March20MAP

CoOccurrance3Inst1Resol30March20NET

The maps are created with the following “thesaurus” to clean the data: Thesaurus 23 March

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to March 23rd, 2020.

by Njal | Mar 23, 2020 | CoOccurrence

Corpus downloaded from PubMed 23rd March: 1323 publications. There were 225 keywords that occurred in three or more manuscripts. These divided into four clusters.

Table of ten most central keywords in each cluster

(Centrality measure used is weighted degree centrality)

Health and pandemic management (Red)	The disease and its pathophysiology (Yellow)	Clinical epidemiology of the disease (Blue)	Treatment of the disease (Green)
coronavirus infection	pneumonia	female	sars
viral pneumonia	outbreak	adult	animals
betacoronavirus	epidemiology	male	genome, viral
china	antiviral agents	middle aged	phylogeny
disease outbreaks	viruses	aged	zoonosis
travel	republic of korea	young adult	wuhan
pandemic	lopinavir	fever	chiroptera
global health	transmission	tomography, x-ray computed	communicable diseases, emerging
infection control	ritonavir	children	disease reservoirs
public health	mortality	lung	peptidyl-dipeptidase a

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CoOccurrance3Inst1Resol23March20MAP

CoOccurrance3Inst1Resol23March20NET

The maps are created with the following “thesaurus” to clean the data: Thesaurus 23 March

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to March 16th, 2020.

by Njal | Mar 16, 2020 | CoOccurrence

Corpus downloaded from PubMed 16th March: 992 publications)

The table below provides an overview of the most central keywords from each of the clusters in the keyword co-occurrence network graph above.

Table of most central keywords in each cluster from the network graph:

Cluster Red	Cluster GREEN	Cluster BLUE	Cluster YELLOW	Cluster PURPLE	Cluster TEAL
Clinical analysis and treatment	Categorization of epidemic	Epidemiology and Global spread	Prognosis for population groups	Origin and definition	Social prevention measures
pneumonia	sars	epidemiology	adult	china	coronavirus infection
infection	mers	australia	female	outbreak	betacoronavirus
novel coronavirus pneumonia	epidemic	case definition	middle aged	viruses	disease outbreaks
public health	pregnancy	emerging infectious diseases	male	wuhan	united states
diagnosis	infant	acute respiratory disease	viral pneumonia	zoonosis	centers for disease control and prevention, u.s.
treatment	bat	importation	aged	respiratory infections	contact tracing
infectious diseases	pandemic	travel	children	transmission	travel-related illness
clinical characteristics	ace2	isolation	radiography, thoracic	respiratory disease	risk assessment
influenza	wuhan pneumonia	quarantine	young adult	cluster	practice guidelines as topic
clinical features	exposure	migration	prognosis	mathematical model	infection control

Bibliometric analyses of COVID-19 research

Applications for the bibliometric Co-occurrence analysis:

Insights and trends

Table of the most central keywords in each cluster

Figure 1: The research focus in the very early Covid-19 literature

Figure 2 (below): The research focus in a later stage of the Covid-19 literature

Tables of most central keywords in each cluster; in literature published during the early phase of the pandemic, and literature published during August.

Table 1: Most frequent keywords in the very early Covid-19 literature

Table 2 (below): Most frequent keywords in a later stage of the Covid-19 literature

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Table of the most central keywords in each cluster

Cluster descriptions

Table of the most central keywords in each cluster

Cluster descriptions

Table of the most central keywords in each cluster

VOSViewer files:

Cluster descriptions

Table of ten most central keywords in each cluster

VOSViewer files:

Cluster descriptions

Table of ten most central keywords in each cluster

VOSViewer files:

Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to April 6th, 2020.

Cluster descriptions

Table of ten most central keywords in each cluster

VOSViewer files:

Cluster descriptions

Table of ten most central keywords in each cluster

Cluster 1 (Red)

Cluster 2 (Green)

Cluster 3 (lBlue)

Cluster 4 (Yellow)

VOSViewer files:

Table of ten most central keywords in each cluster

Health and pandemic management (Red)

The disease and its pathophysiology (Yellow)

Clinical epidemiology of the disease (Blue)

Treatment of the disease (Green)

VOSViewer files:

Table of most central keywords in each cluster from the network graph:

Cluster Red

Cluster GREEN

Cluster BLUE

Cluster YELLOW

Cluster PURPLE

Cluster TEAL

Clinical analysis and treatment

Categorization of epidemic

Epidemiology and Global spread

Prognosis for population groups

Origin and definition

Social prevention measures

Health and pandemic management
(Red)

The disease and its pathophysiology
(Yellow)

Clinical epidemiology of the disease
(Blue)

Treatment of the disease
(Green)