References for Signs of COVID-19 by journal

Laboratory results showed that there were significant differences in white blood cell counts, absolute values of lymphocytes, platelets, albumin, total bilirubin, blood urea nitrogen, blood creatinine, myoglobin, cardiac troponin, C-reactive protein (CRP) and interleukin-6 (IL-6) between those who died from COVID-19 and those who survived.

Laboratory Results of COVID-19 Patients in Wuhan, China

- 12 (50.0%) of asymptomatic infections showed typical ground-glass or patchy shadows in their CT images. 
- 5 (20.8%) of asymptomatic infections showed atypical striped shadows in CT images of their lungs.
- 7 (29.2%) displayed normal CT images.

Radiological Results of COVID-19 Asymptomatic Cases in Nanjing, China

- 4 (16.7%) of infections presented with lymphopenia. An additional 4 (16.7%) leukopenia.
- Abnormal levels of alanine aminotransferase, aspartate aminotransferase, creatine kinase, C-reactive protein and D-dimer were rare. 

Laboratory Results of COVID-19 Asymptomatic Cases in Nanjing, China

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


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Syracuse University

"a sign is any objective evidence of a disease that can be observed by others (for example a skin rash or lump)."

Signs of Disease

- 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

Several studies have shown that COVID-19 can be transmitted by individuals who do not show any symptoms, or who are "asymptomatic". Because asymptomatic individuals are not routinely tested, the prevalence of asymptomatic infection is not well-defined.

Asymptomatic COVID-19 Infection

Hu, Z., Song, C., Xu, C., Jin, G., Chen, Y., & Xu, X. et al. (2020). Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing, China. Science China Life Sciences, 63(5), 706-711. https://doi.org/10.1007/s11427-020-1661-4

Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing, China

Clinical Characteristics of Asymptomatic 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

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

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 

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

Psychological Effects of COVID-19 Pandemic

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

COVID-19 Patient Comorbidities

- 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

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

Risk Factors For 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

Previous reports indicate that asymptomatic transmission is possible, but since they’re hard to track, this poses a significant challenge to infection control practices.

Implications of Asymptomatic COVID-19 Transmission

- China
- Germany
- Japan
- USA
- Singapore

Asymptomatic COVID-19 Infection Categorized by Country

- Travel Medicine and Infectious Diseases References
-Science China Life Sciences
-Journal of American Medical Association (JAMA)
- New England Journal of Medicine (NEJM)
- Euro Surveillance
- Morbidity and Mortality Weekly Report (MMWR)
- Nature Medicine

Asymptomatic COVID-19 Infection References by Journal

- Viral shedding
- IgG levels
- Low white blood cell count (lymphopenia)
- Low blood platelet count (thrombocytopenia)
- Chest CT focal ground-glass opacities
- Chest CT stripe shadows

Clinical and Immunological Results of Asymptomatic COVID-19 Infection

Due to the SARS-CoV-2 viral load being similar between asymptomatic and symptomatic healthcare workers with COVID-19, asymptomatic healthcare workers donning less PPE may be a risk factor for other colleagues, patients, and the community.

Healthcare Workers with Asymptomatic COVID-19 Infection

In addition to symptomatic screening, additional control/detection methods are routine rRT-PCR testing, conservative guidelines for reopening, and periodic testing are important for epidemiological evaluations. Facilities using these methods include nursing homes and other congregate living situations such as prisons, mental health facilities, and homeless shelters.

Additional control/detection methods to prevent asymptomatic transmission

Studies have shown that even though asymptomatic people have the same viral load, they have increased levels of lymphocytes (CD4+cells) as compared to symptomatic people, which may lead to them being asymptomatic. Due to the presence of increased lymphocytes, they also clear the viral particles faster and show lower risk of long term complications. 



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