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 2020: Click here
Growth in number of documents by month:
Date | Nr. of docs in PubMed |
2020 | |
16th March | 992 |
6th April | 2684 |
4th May | 8791 |
1st June | 17356 |
6th July | 28256 |
3rd August | 36201 |
7th September | 48067 |
5th October | 56023 |
2nd November | 64184 |
4th December | 74801 |
2021 | |
3rd January | 87286 |
7th February | 97147 |
7th March | 106888 |
7th April | 116545 |
2nd May | 125521 |
6th June | 136870 |
4th July | 146730 |
2nd August | 154918 |
5th September | 165638 |
3rd October | 174892 |
7th November | 185423 |
5th December | 194349 |
2022 | |
2nd January | 202962 |
6th February | 213578 |
6th March | 222742 |
3rd April | 231268 |
Keyword Co-Occurrence Network Graph for the Overall Research Field on COVID-19 up to June 1st, 2020.
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.
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.
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.
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 |
To open the map directly in VOSviewer, please use these two files.
KeywordCoOccurrance_20200511_NET
KeywordCoOccurrance_20200511_MAP
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 4th, 2020.
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 |
To open the map directly in VOSviewer, please use these two files.
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.
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 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”.
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 |
VOSViewer files:
To open the map directly in VOSviewer, please use these two files.
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.
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 |
VOSViewer files:
To open the map directly in VOSviewer, please use these two files.
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.
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 |
VOSViewer files:
To open the map directly in VOSviewer, please use these two files.
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.
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 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 | 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 |
VOSViewer files:
To open the map directly in VOSviewer, please use these two files.
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.
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 |
VOSViewer files:
To open the map directly in VOSviewer, please use these two files.
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.
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
|
The disease and its pathophysiology
|
Clinical epidemiology of the disease
|
Treatment of the disease
|
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 |
VOSViewer files:
To open the map directly in VOSviewer, please use these two files.
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.
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 |