- AIDS and Behavior
- American Journal of Cancer Research
- American Journal of Hypertension
- American Society of Clinical Oncology Journals
- Annals of Allergy, Asthma & Immunology
- Annals of Internal Medicine
- Annals of Oncology
- Blood Advances
- BMC
- Brain, Behavior, and Immunity
- Cancer Discovery
- Cell Metabolism
- Clinical Immunology
- Clinical Infectious Diseases
- Clinical Reviews in Allergy & Immunology
- Clinical Transplantation
- Cureus
- Diabetes Care
- Diabetes & Endocrinology
- Diabetes & Metabolic Syndrome: Clinical Research & Reviews
- Diabetes, Obesity, and Metabolism
- Diabetes Research and Clinical Practice
- EClinicalMedicine
- European Journal of Cardio-Thoracic Surgery
- European Journal of Clinical Nutrition
- European Respiratory Journal
- Frontiers in Medicine 
- Frontiers in Public Health
- Gut
- Haematologica
- International Journal of Infectious Diseases
- International Journal of Obesity
- Journal of Alzheimer’s Disease
- Journal of American Nephrology
- Journal of Clinical Medicine
- Journal of Endocrinological Investigation
- Journal of Infection
- Journal of Infectious Diseases
- Journal of Intensive Care Medicine
- Mayo Clinic Proceedings
- Medicine
- Nature
- Nutrition, Metabolism & Cardiovascular Diseases
- Obesity
- Obesity Research & Clinical Practice
- Oxford Academic Journals
- Paediatric Respiratory Reviews
- Polish Archives of Internal Medicine
- Practical Diabetes
- PRiMER (Peer-Reviewed Reports in Medical Education Research) 
- Proceedings of the National Academy of Sciences 
- Public Library of Science
- The Brazilian Journal of Infectious Diseases
- The Journal of the American Medicine Association Cardiology
- The Journal of Allergy and Clinical Immunology
- The Lancet
- The National Center for Biotechnology Information
- The New England Journal
- Thrombosis Research
- Translational Stroke Research 

COVID-19 Comorbidities References by Journal

COVID-19 may be worse in patients with comorbidities, and this can cause damage to the heart, liver, kidneys, and blood and immune systems. Many patients have had multiple organ failure that started with pneumonia, and became worse when therapeutic effects were unsatisfactory. Comorbidities can cause a patient's deterioration, leading to multiple organ failure. Organ function should be closely monitored and protective measures such as mechanical ventilation, glucocorticoids, antivirals, symptomatic treatments, and anti-shock therapy should be administered if necessary. 

Multiple Organ Injuries in COVID- 19 Patients with Comorbidities

- Implication of Obesity In Patients with COVID-19 
- Obesity in COVID-19 Patients by Geographic Location 
- Risk of Cytokine Storm in Obese COVID-19 Patients
- Higher Concentrations of IL-17 and TNF-α Lead to Greater Respiratory Damage
- Association of Obesity and Age with severe cases of COVID-19
- Association of Obesity and Hospital Stay Length

Obesity as a Comorbidity of COVID-19 

- Hypertension and COVID-19 by Geographic Location
- Hypertension and COVID-19 by Topic

Hypertension as a Comorbidity of COVID-19

- Respiratory System Disease in COVID-19 Patients by Geographic Location 
- Asthma as a Comorbidity of COVID-19

Respiratory System Disease as a Comorbidity of COVID-19

- Clinical Features and Outcomes of Patients With Human Immunodeficiency Virus With COVID-19
- The Burden of COVID-19 in People Living with HIV: A Syndemic Perspective (General Summary of HIV and COVID-19 Interaction)
- Maintaining HIV care during the COVID-19 pandemic
- HIV in COVID-19 Patients by Geographic Location
- COVID-19 and HIV Coinfection

HIV as a Comorbidity of COVID-19

- By country
- Liver Transplantation
- Chronic Liver Disease

Liver Injuries as a Comorbidity of COVID-19 

- This node acts as a general summary of the comorbidity of cancer and COVID-19 from a paper that analyzed many other papers detailing the same thing at its time of release.
- Via a pooled meta-analysis of studies from around the globe analyzing the prevalence of cancer in COVID-19 patients, it was found that the prevalence of cancer in COVID-19 patients is about 2%, which is higher than the overall prevalence of cancer in the population (I think).
- This leads to a hypothesized conclusion that while there is not a lot of data for COVID-19 infection and cancer patients, there is an elevated risk for these patients. However, due to inconclusive and generally lacking data on this topic, this conclusion is not concrete.
- Many major cancer centers worldwide have taken extra precaution when it comes to the treatment of these patients as many cancer treatments (e.g., chemotherapy) weaken the immune system as a side effect.
- There has currently been no order to withhold chemotherapy, radiotherapy, immunotherapy, or delaying adjuvant therapy to treat cancer patients, however extra care must be taken by patients and physicians alike to not allow these high-risk patients to become infected.

Cancer as a Comorbidity of COVID-19 

Patients with digestive diseases like inflammatory bowel disease (IBD) or gastrointestinal cancer are at a higher risk to experience more severe symptoms of COVID-19. Autopsy studies are important in understanding how COVID-19 affects the digestive system. More data needs to be collected to determine the exact relationship between digestive diseases and COVID-19. 

Digestive Diseases as a Comorbidity of COVID-19

- Cytokine Storm Syndrome
    -  Secondary Haemophagocytic Lymphohistiocytosis
- Common Variable Immunodeficiency 
- Figure illustrating how pathogenic T cells and inflammatory monocytes enter pulmonary circulation and incite an inflammatory storm and immune disorder 
- Severe Combined Immunodeficiency

Immunological Diseases as a Comorbidity of COVID-19

- Prevalence of pathophysiology, prognosis, and practical considerations
- Knowledge in progress
- The link between diabetes and ACE2
- Diabetes in COVID-19 patients by geographic location 
- Degree of Hyperglycemia on COVID-19 mortality
- Diabetes Medication on COVID-19 mortality
- COVID-19 and endocrine diseases. A statement from the European Society of Endocrinology

Diabetes as a Comorbidity of COVID-19

During the COVID-19 era the regular treatment and communication between physicians and patients regarding preexisting comorbidities has been disrupted. New guidelines and safety precautions must be put in place in order for physicians to still treat their patients and treat them through the use of telehealth or other means. While there are a lot of similarities between new communication policies being implemented across different areas of medicine, there are also many differences due to comorbidity specific criteria which facilitates different levels of involvement and communication between physicians and patients.


The comorbidities addressed under this node include:
- Cancer
- Cardiovascular Diseases
- Digestive Diseases
- Elective Surgeries
- Liver Diseases
- Psychological Disorders
- Renal Diseases

Changes to COVID-19 Patient Comorbidity Treatment and Communication

Cardiovascular disease is a risk factor for severe COVID-19, and COVID-19 causes cardiovascular complications. 

Cardiovascular Disease and COVID-19

- A retrospective multi-center experience of renal transplants from India during COVID-19 pandemic

Renal Diseases as a Comorbidity of COVID-19

COVID-19 comorbidities are high risk conditions that put patients at greater risk for infection and negative outcomes. Some COVID-19 comorbidities have been found to be: 
- Cancer 
- Cardiovascular Disease
- Diabetes
- Digestive Diseases
- HIV
- Hypertension
- Immunological Disease
- Liver Injury
- Obesity
- Renal disease
- Respiratory System Disease

University of Michigan - Ann Arbor

Smith College

City University of New York

Ohio State University, Columbus

University of California, Berkeley

Syracuse University

- Affected organs and organ systems
- Circadian Physiology in relation to COVID-19
- Exercise/Physical Activity and COVID-19
- Immune response to COVID-19
- Laboratory methods
- Pathogenesis
- Patient comorbidities 
- Symptomology 
- Genetic mechanisms in COVID-19
- The body's response to stress hormones






Focuses of Human physiology studies on COVID-19

- Case Demographics of Patients
- Categorized by Geographic Location
- Communicable Period
- Control Strategies
- Disparate COVID-19 Outcomes
- Fatality
- Interventions
- Patient Comorbidities
- Patient Laboratory Results
- Psychological effects
- Recovery & Rehabilitation
- Re-opening of Childcare/ Educational Environments
- Secondary Infections
- Signs
- Symptomology
- Time from Onset to Reporting
- Telehealth (telemedicine)
- Transmission
- Risk Factors
- COVID-19 Vaccination Uptake

Focuses of Epidemiological studies on COVID-19

Around 1 out of every 6 people who gets COVID-19 becomes seriously ill and develops difficulty breathing.  Other factors may increase the risk of severe symptoms

Rate of Appearance of Severe Symptoms

- smoking
- high BMI
- old age
- congregate housing
- environmental conditions
- Immune system conditions

Risk Factors For COVID-19

Retrospective epidemiological studies using clinical data and experimental molecular biologies studies have revealed biomarkers of COVID-19.  These elements not only reveal how COVID-19 mechanistically affects the body, but they may also be risk factors for developing severe symptoms and act as targets for pharmacological intervention.  They include:

- A1AT protection
- ACE2 expression and activity
- ADAM17 sheddase activity
- Furin protease activity
- Irregular respiratory function
- Pro-inflammatory cytokine concentration in the plasma
- TMPRSS2 serine protease genetic variation
- Variation in genetic susceptibility to SARS-CoV-2
- Viral interactions with glycosaminoglycans
- Nsp (Non-specific Protein) Activity
- Neuropilin-1 expression


Pathogenesis of COVID-19

Current studies show that many organs that are heavily affected by COVID-19 have a high expression level of ACE2.

- Cardiovascular system
- Central nervous system (CNS)
- Gastrointestinal tract (GI)
- Kidney
- Liver 
- Lungs (Respiratory System)
- Peripheral nervous system (PNS)
- Testis

Organs and Organ Systems Affected by COVID-19

- Animal models
- Cell lines
- Genetically engineered SARS-CoV-2

Laboratory Methods in COVID-19 Research

Infection by SARS-CoV-2, as is with other viral infections, induces a two-phased immune response in the human body, described in the figure below: 
- Innate (rapid, natural, non-specific) 
- Adaptive (slow, acquired, specific)

Those two branches of the immune system cooperate with one another, and can be distinguished based on the cell-types involved (immune response vs white blood cells). However, the adaptive system is further broken down by the type of mechanism:

- Cell-mediated
- Antibody-mediated

Current research around COVID-19 immunity aims at uncovering the interaction between SARS-CoV-2 and the host's immune response, with questions related to pathogenesis, severity, and intervention.

Immune Response to COVID-19 

Presence and severity of symptoms of COVID-19 depend largely on individual characteristics. COVID-19 produces both symptomatic and asymptomatic infection.

Symptomology of COVID-19 

- Pituitary gland: improper functioning of the hypothalamus in association with pituitary gland; changes the metabolism of ADH (regulates the amount of water in the kidneys); abnormal sodium levels
- Thyroid: sick euthyroid syndrome → decrease in size of thyroid gland; changes in TSH levels
- Adrenal gland: increased chance of COVID-19 infection if presented with Cushing’s syndrome (too much cortisol) or Addison’s disease (inadequate aldosterone and cortisol)
- Pancreas: those with diabetes are at higher risk of getting COVID-19
- Bone: low vitamin D and hypocalcemia

Dysfunctions/ diseases in endocrine glands/organs that could lead to greater susceptibility to COVID-19

Exercise and physical activity induce physiological changes on many levels, the effects of which are best understood using a biopsychosocial approach.  The bidirectional relationship between exercise and Covid-19 can be further broken down into different components:
- Exercise/PA and COVID-19 by geographical location
- Exercise/PA and COVID-19 by demographics


Exercise/Physical Activity (PA) and Covid-19

COVID-19 Patient Comorbidities

Circadian biology refers to any biological process that has a rhythmic component dependent on time of day.  Understanding the relation between COVID-19 and circadian rhythm could help improve clinical management in treating COVID-19.

Circadian Physiology in relation to COVID-19

ARTICLES RESEARCHED
- Genetic mechanisms of critical illness in Covid-19
- Epigenetic dysregulation of ACE2 and interferon-regulated genes might suggest increased COVID-19 susceptibility and severity in lupus patients

Genetic mechanisms in COVID-19

Levels of stress may increase in those diagnosed with COVID-19, resulting in an alteration in stress hormone levels and the body's ability to cope with the stress.

The Body's Physiological Response to Stress Hormones In COVID-19 Patients

Due to differences in testing and case definitions, as well as how new COVID-19 is, the fatality of the virus is not well-defined yet.

Fatality of COVID-19

Countries have implemented multiple control strategies for reducing the spread of COVID-19, such as closing schools and businesses to enforce social distancing.

Struggle pertaining to controlling the virus:
The epidemiology of the respiratory virus changes rapidly. Reponses have to be nimble. Given that everyone is susceptible to for which we lack effective biologic interventions, the response has required large-scale behavior change, including social distancing and public masking.

Control Strategies for COVID-19

- Age
- Education
- Employment
- Ethnicity
- Gender
- Income
- Marital status
- Race





Case Demographics of Patients with COVID-19

- Asia
- Africa 
- North America
- South America
- Europe
- Australia & Oceania 

Epidemiological studies on COVID-19 Categorized by Continents

The progression of COVID-19 varies greatly by individual and demographic, as do many of the factors related to the disease. Studies have been analyzing the disease progression timeline, or the time frames before patients feel symptoms, are admitted to the hospital, are admitted to the ICU, are put on a mechanical ventilator, experience acute respiratory distress syndrome, etc. Not every COVID-19 case will reach each of these events.

COVID-19 Clinical Disease Progression Timeline

- 0-19 (n=123): 0%
- 20-44 (n=705): 0.1–0.2%
- 45-54 (n=429): 0.5–0.8%
- 55-64 (n=429): 1.4–2.6%
- 65-74 (n=409): 2.7–4.9%
- 75-84 (n=210): 4.3–10.5%
- greater than or equal to 85 (n=144): 10.4–27.3%
- Total (n=2,449): 1.8–3.4%

Case-Fatality Among COVID-19 Patients in the United States by Age

Following a primary infection of SARS-CoV-2, some patients acquire a secondary infection of SARS-CoV-2, or a co-infection with a different bacteria or virus

Secondary/Co-Infections of COVID-19

COVID-19 patients have gone through laboratory testing to determine the impact and extent of SARS-CoV-2 on the body.

COVID-19 Laboratory Results

The spread of the SARS-CoV-2 virus has produced or highlighted disparate outcomes of different types between population groups all over the world. Health disparities can highlight inequitable access, treatment, etc. within a country or state and often indicate the need for public health intervention.

Disparate COVID-19 Outcomes

Due to the varying experiences for those with COVID-19, recovery and rehabilitation look different for many individuals. As a baseline, "for persons recovered from COVID-19 illness, CDC recommends that isolation be maintained for at least 10 days after illness onset and at least 3 days (72 hours) after recovery. Illness onset is defined as the date symptoms begin. Recovery is defined as resolution of fever without the use of fever-reducing medications with progressive improvement or resolution of other symptoms. Ideally, isolation should be maintained for this full period to the extent that it is practicable under rapidly changing circumstances."

COVID-19 Recovery & Rehabilitation

- Resuscitation
- Convalescent Plasma (CP) Transfusion

COVID-19 Patient Interventions

The seroprevalence of COVID-19 is the measurement of the level of the pathogen in a population. There have been difficulties with estimating the seroprevalence in large populations because of the unknown qualities of COVID-19, expense in widespread population collection, asymptomatic infection, etc.

Seroprevalence of SARS-CoV-2 (COVID-19) 

A communicable period is defined as the interval from the first day of positive ribonucleic acid test to the first day of continuous negative test. For COVID-19, the communicable period has been established as two days before onset of symptoms until three days of symptom relief and no fever. 

Communicable Period of COVID-19

- Fever (when high temperature is measured)
- Laboratory confirmation of illness via viral testing
- Radiological lung abnormalities such as ground-glass chest and stripe shadowing


Clinical Characteristics of Asymptomatic COVID-19 Patients

Telehealth are health-related services and information through electronic communication technologies to help patients with or people influenced by COVID-19. It allows long-distance patient and clinician care, education, and monitoring. Telemedicine is sometimes used as a synonym, or is used in a more limited sense to describe remote clinical services, such as diagnosis and monitoring. 

Telehealth (telemedicine) and COVID-19

The psychological effect COVID-19 is having on the populations affected by the pandemic

Psychological Effects of COVID-19 Pandemic

- Schools (K-12)

- Universities/Colleges

- Summer Camps

- Daycares

- Nurseries

Re-opening Childcare/ Educational Environments

COVID-19 is spread through person-to-person transmission. The virus spreads mainly through close personal contact (such as when people are within 6 feet of one another) and through the respiratory droplets of someone infected with COVID-19.  Aerosol transmission is also likely, but the relative contribution of these smaller respiratory particles is not completely understood. While less common, spreading can also occur when people touch contaminated objects or surfaces and then their faces, eyes, or mouth. 

Transmission of COVID-19

We can explore factors that affect the uptake of established adult vaccinations to inform efforts of COVID-19 vaccine acceptance. 

- Social Factors 
- Knowledge, Attitudes, and Beliefs
- Racial Factors
- Age

COVID-19 Vaccination Uptake

Smoking as a Risk Factor for COVID-19

Varying environmental conditions could increase the risk for some groups of individuals to be exposed to COVID-19. Example environmental conditions include:   
 - Rain 
 - Wildfires

Impact of Environmental Conditions on COVID-19

People with weakened immune systems are at higher risk of getting severely sick from SARS-CoV-2. Because of this, they have the infection for a longer period of time due to their immune system not fighting it off as fast. If you are immunocompromised, the best way to prevent COVID-19 is to avoid being exposed to this virus. Precautions such as washing hands, cleaning surfaces have to be done more frequent for people with suppresed immune systems.

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