Health Information on the 2019 Coronavirus
A Policy Brief of the Howard H. Baker Jr. Center for Public Policy
March 13, 2020
Using publicly available data on influenza and emerging research on COVID-19, this brief provides details on COVID-19 transmission, contagiousness, disease burden, and suggested guidelines on limiting the spread of the infection. This brief is part of a series that will be produced over the next few weeks forecasting the health and economic impact of the virus. The Department of Health for the State of Tennessee is also providing ongoing updates. As this is an emerging issue dealing with a novel virus, information included here is potentially subject to revision as new research and data emerge.
On December 31, 2019, the World Health Organization’s (WHO) China Country office was informed about cases of pneumonia with an unknown cause that had been detected in Wuhan City, located in the Hubei Province. Over the next three days, from the 31st to the 3rd of January, 2020, a total of 44 cases were reported to WHO by the national authorities in China. On February 11, 2020, the WHO announced that the disease caused by the new coronavirus would be known by the official name of COVID-19.
COVID-19 causes respiratory symptoms, including fever, cough, shortness of breath, and other breathing difficulties. In severe cases, the infection can cause pneumonia, severe acute respiratory syndrome, kidney failure, and death.
As of noon, on Friday, March 13, 2020, according to tracking of COVID-19 by Johns Hopkins University, the virus has spread to:
Global: over 137,385 cases in more than 114 countries, with 5,088 deaths and 69,779 people recovered
United States: 1,268 cases, 33 deaths, 6 recoveries
Tennessee: 18 cases, 0 deaths, 0 recoveries
- Davidson: 6
- Knox: 1
- Shelby: 2
- Sullivan: 1
- Williamson: 8
COVID-19 has similar symptoms and transmission modes to influenza, spreads more slowly, and is less likely to affect children, but cases of it are more contagious, are more likely to be severe, and more likely to be deadly. There is no cure and no vaccine.
According to guidance from the Center for Disease Control (CDC), to avoid spreading the illness:
avoid close contact with those who are sick (a minimum of 3 feet), avoid touching your eyes, nose, and mouth, stay home if you are feeling sick or if you have been traveling internationally, cover your cough or sneeze with a tissue and throw the tissue in the trash, clean and disinfect frequently touched objects and surfaces using bleach or ethyl alcohol dilutions (60-70%), wash your hands often with soap and water for 20 seconds, avoid public transit and closed-in spaces where air is recirculated.
stock up on necessary supplies to limit the need to leave your home, take precautions to keep space between yourself and others (a minimum of 6 feet), when in public keep away from others who are sick, limit close contact, and wash your hands frequently with soap and water for 20 seconds, avoid crowds as much as possible, avoid cruises and other non-essential travel, and during the event of a COVID-19 outbreak in your community, stay home as much as possible to reduce the risk of exposure.
With any disease there are two main modes of transmission: direct and indirect. In direct transmission, the pathogen is transmitted by direct contact between a diseased subject and a non-diseased subject. Direct transmission can occur when an infected person touches or exchanges body fluids with someone else, including in the form of droplet spread—that is relatively large, short-range aerosols produced by sneezing, coughing, or speaking.
In indirect transmission, the pathogen is transmitted between a diseased subject and a non-diseased subject by an intermediary, such as air particles, inanimate objects (vehicles), or animate intermediaries (vectors) that can carry infection. Airborne transmission occurs when an infectious agent is carried by dust or droplet nuclei (<5 microns in size) suspended in the air, potentially traveling over expansive areas. Vehicle transmission occurs when an infectious agent is passively transmitted by inanimate objects, such as food, water, and fomites— objects or materials that can carry infection, such as hard surfaces and materials. Vector transmission occurs when an infectious agent is transmitted by an intermediate organism, including animals and insects.
COVID-19 appears to be transmitted directly, person-to-person in close contact (within 6 feet), through droplet spread produced when an infected person coughs or sneezes.
Given the possibility that transmission may occur indirectly due to contact with contaminated surfaces, it is important to note that based on a recent 2020 study published in the Journal of Hospital Infection on human coronaviruses (not specifically COVID-19) human coronaviruses:
Another consideration for disease transmission is its basic reproduction number, sometimes denoted as R0 (pronounced R nought), which is the number of cases that can be expected to be generated by one infected case in a population where all individuals are susceptible to the virus. Notably, this figure also includes an assumption that no attempts are made to curb the transmission of the disease. The R0 figure can be thought of as an indication of the contagiousness of a disease.
In a 2020 article published in the Journal of Travel Medicine researchers examined 12 studies published from January 1, 2020 and February 7, 2020 that had estimated the R0 of COVID-19. The review found an average R0 of 3.28 across the studies, meaning in a susceptible population and without intervention, each infected individual would likely infect three or more others on average. This research also found that the median R0 of the studies examined was 2.79, which the authors noted exceeded the WHO estimates of a range between 1.4 and 2.5. This is a higher than the estimated contagious rate than influenza.
The flattening of the R0 curve, and to avoid such outcomes, the infection rate can be slowed through the public health interventions, including non-pharmaceutical interventions (NPIs), like social distancing— which includes everything from self-isolation and school closures, to limiting handshakes and other forms of interpersonal contact—strategies that are discussed more in-depth below.
The CDC has provided the following further guidance on underlying conditions that may increase the risk of serious COVID-19 for individuals at any age:
- Blood disorders (e.g., sickle cell disease or on blood thinners)
- Chronic kidney disease as defined by your doctor. Patient has been told to avoid or reduce the dose of medications because kidney disease, or is under treatment for kidney disease, including receiving dialysis
- Chronic liver disease as defined by your doctor (e.g., cirrhosis, chronic hepatitis). Patient has been told to avoid or reduce the dose of medications because liver disease or is under treatment for liver disease.
- Compromised immune system (immunosuppression) (e.g., seeing a doctor for cancer and treatment such as chemotherapy or radiation, received an organ or bone marrow transplant, taking high doses of corticosteroids or other immunosuppressant medications, HIV or AIDS)
- Current or recent pregnancy in the last two weeks
- Endocrine disorders (e.g., diabetes mellitus)
- Metabolic disorders (such as inherited metabolic disorders and mitochondrial disorders)
- Heart disease (such as congenital heart disease, congestive heart failure and coronary artery disease)
- Lung disease including asthma or chronic obstructive pulmonary disease (chronic bronchitis or emphysema) or other chronic conditions associated with impaired lung function or that require home oxygen
- Neurological and neurologic and neurodevelopment conditions [including disorders of the brain, spinal cord, peripheral nerve, and muscle such as cerebral palsy, epilepsy (seizure disorders), stroke, intellectual disability, moderate to severe developmental delay, muscular dystrophy, or spinal cord injury]
- less than or equal to 80 years old: 3% (1,408 cases)
- 30-79 years: 87% (38,680 cases)
- 20-29 years: 8% (3,619 cases)
- 10-19 years: 1% (549 cases)
- less than 10 years old : 1% (416 cases)
This is also displayed in the figure below.
COVID-19 Disease Burden
In comparison, for the 2019-2020 US influenza season, 57.9 cases in 100,000 required hospitalization. Even for the most susceptible population to influenza, which is those over the age of 65, for the 2019-2020 influenza season, there were 147.5 cases of hospitalizations in 100,000. The hospitalization rate projected for COVID-19 is exponentially higher than the rate for influenza, even when considering the highest risk populations.
- Mild: 81% (36 ,160 cases)
- Severe: 14% (6,168 cases)
- Critical: 5% (2,087 cases)
This is displayed in the figure below.
This indicates that an estimated:
- 3,000 cases will require oxygen per 100,000 cases of COVID-19
- 1,000 cases will require ventilation per 100,000 cases of COVID-19
Notably the CDC estimates that the burden of illness during the 2018–2019 influenza season in the US included an estimated:
- 35.5 million cases of influenza
- 16.5 million saw a health care provider for their illness
- 490,600 required hospitalization
- 34,200 died from influenza
According to the CDC, the number of influenza-associated illnesses that occurred last season was similar to the estimated number of influenza-associated illnesses during the 2012–2013 influenza season when an estimated 34 million people had symptomatic influenza illness.
COVID-19 Case Fatality Rate
The crude case fatality rate (CFR) is how epidemiologists calculate the killing power of a disease. The CFR for any illness can be calculated by the following formula (here presented by 1,000, though by 100 cases is most common):
Some have noted that the global crude case fatality rate may be inflated due to the lack of widespread testing, or because those with mild symptoms have not been tested. This is a legitimate critique and is also known as ascertainment bias.
- 45 times (4.5%) more deadly than influenza based on Hubei Province, China, which includes the city of Wuhan
- 45 times (4.5) more deadly than influenza based on Iran
- 67 times (6.7%) more deadly than influenza based on Italy
- 8 times (0.83%) more deadly than influenza based on South Korea
- 28 times (2.8%) more deadly than influenza based on Spain
- 2 times (0.22%) more deadly than influenza based on Germany
- 21 times (2.1%) more deadly than influenza based on France
- 2.3% of all confirmed cases (1,023 of 44 ,672 confirmed cases)
- 8.0% in patients 70-79 years or older (312 of 3,918)
- 14.8% in patients who are 80 years or older (208 of 1,408)
- 49.0% in cases that become critical (1,023 of 2,087)
Best Practices and Prevention for Tennessee
When confronting pandemic illnesses, mitigating the social and economic consequences through early and targeted non-pharmaceutical interventions (NPIs), also known as community mitigation strategies, is critical. These are strategies that local governments, social organizations, and businesses can implement apart from those taken within a clinical setting. According to the CDC, the rationale of community mitigation is threefold:
- Delay the exponential growth in infection rates, which spreads the distribution of cases thereby affording time for healthcare entities to prepare for a surge in demand.
- Reduce the peak number of active cases.
- Reduce the overall quantity of cumulative cases, thereby reducing morbidity and mortality.
Pandemic outbreaks can overwhelm healthcare systems and critical infrastructure at both the local and national level, which may compromise the quality and availability of medical care. Research shows social distancing and closures can help mitigate the impact by limiting disease transmission, reducing morbidity, and lowering mortality.
To be clear, by slowing the rate of COVID-19 and therefore lowering the number of active cases at any given time, the burden placed on healthcare infrastructure can be more evenly distributed, reducing the strain on medical professionals and facilities in addressing individual cases. Ultimately, community mitigation strategies are aimed at protecting vulnerable populations most at risk of severe illness and groups that many be more socially or economically impacted by a pandemic.
Disclaimer: the information in this policy brief was produced by researchers, not medical or public health professionals, and is based on their best assessment of the existing knowledge and data available on the topic. It does not constitute medical advice and is subject to change as additional information becomes available.
Dr. Katie A. Cahill
Cahill is the Associate Director of the Howard H. Baker Jr. Center for Public Policy. She also is the Director of the Center's Leadership & Governance program and holds a courtesy faculty position in the Department of Political Science. Her area of expertise is public health policy. She leads the Healthy Appalachia project.
Sale is an undergraduate student researcher with the Center. He is a senior majoring in economics with a minor from the Center's public policy analytics program. He has worked on an NSF-funded project regarding rebel group grievances, as well as in supporting The White House's American Workforce Policy Advisory Board.
Dr. Kathleen C. Brown, MPH
Brown spent eight years working for the Knox County Health Department, initially as the regional epidemiologist, and then as the Director of Community Assessment and Health Promotion. She is an Associate Professor of Practice (non-tenure) in the Department of Public Health and the Program Director for the Master's in Public Health (MPH) degree.
Dr. Matthew N. Murray
Murray is the Director of the Howard H. Baker Jr. Center for Public Policy. He also is the Associate Director of the Boyd Center for Business and Economic Research and is a professor in the Department of Economics in the Haslam College of Business. He has led the team producing Tennessee's annual economic report to the governor since 1995.
Dr. Charles Sims
Sims is the Director of the Center's Energy & Environment program. He also is an associate professor in the Department of Economics in the Haslam College of Business. Sims has active research grants with the Sloan Foundation, USDA, and TVA. He has previously worked on projects involving invasive species and infectious diseases.