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Salem Health: Infectious Diseases & Conditions, 2nd Edition

COVID-19 Disease

by H. Bradford Hawley, , M.D.

Category: Diseases and conditions

Anatomy or Systems Affected: Respiratory system

Also Known As: SARS-CoV-2, 2019-nCoV, novel betacoronavirus

Definition

COVID-19 is a respiratory disease caused by a novel betacoronavirus that can produce illness ranging from mild, or even asymptomatic, to severe, life-threatening pneumonia. The virus is highly contagious and has spread worldwide causing a pandemic.

Causes

On December 31, 2019, China reported a cluster of pneumonia cases associated with the Huanan Seafood Market in the city of Wuhan. One week later it was announced that the infectious agent was a novel coronavirus. The Chinese market sold a variety of live animals, including bats; the virus is thought to have originated in bats with direct transfer to humans or indirect transfer to humans through an intermediate animal host. The virus is similar to another betacoronavirus -- SARS -- originating in Chinese live animal markets in 2003 causing severe respiratory distress syndrome. The first case of COVID-19 in the United States occurred on January 19, 2020, in Snohomish County, Washington state. The patient was a 35-year-old man who had just returned from visiting his family in Wuhan, China.

The COVID-19 virus can be spread by airborne droplets, contact with contaminated surfaces with entrance through mucous membranes, and possibly by fecal-oral routes as the virus has been shown to be shed in the feces of infected individuals. After exposure, the incubation period is usually about five days but may be up to two weeks.

Risk Factors

This is a new virus, so no one is immune to infection. Older age, immunocompromised status, underlying diseases, and smoking have all been associated with more severe disease. COVID-19 is highly transmissible, and close contact with an infected individual or contaminated surface should be avoided. Healthcare workers are at an increased risk and must wear gloves, gowns, and N-95 respirators to protect themselves from infection. Masks should be worn by infected or suspected patients to decrease the chance of spreading infection. Wearing of regular masks by uninfected individuals does not reliably protect against infection as they are not occlusive against aerosols and leave the eyes unprotected.

Symptoms

Some infected persons will have few or no symptoms. Children usually have mild disease with cold-like symptoms often with no fever. Adults will have fever, headache, sore throat, dry cough, and shortness of breath in more severe cases. There can also be a feeling of fatigue and general malaise with accompanying myalgia. Viral pneumonia occurs with severe disease and results in impaired oxygenation manifested by shortness of breath. Such patients need immediate medical care and hospitalization.

Screening and Diagnosis

During the current pandemic, any patient with new respiratory symptoms, especially if accompanied by fever, must be considered possibly infected with COVID-19. Additionally, any patient coming from a highly infected country, cruise ship, or area with a high prevalence of COVID-19 infection must be considered possibly infected even if they are asymptomatic. Screening may initially be done to rule out other respiratory pathogens such as influenza virus. Definitive testing for COVID-19 is accomplished by taking two swabs, one from the nose and one from the throat, which are then sent to a microbiology laboratory with the capability to perform specific polymerase chain reaction (PCR) testing. This test can identify viral genetic material. Because the genetic material (RNA) of this coronavirus is very large and capable of evolving mutations, the PCR probe has been designed to target two specific genetic areas to avoid missing cases. It is possible to have a negative PCR test very early in the COVID-19 infection when only small amounts of the virus are present.

Radiological examinations are also helpful in diagnosis. Computerized tomography (CT) scanning often reveals characteristic features in COVID-19 pneumonia patients. Sometimes the findings from these exams can provide a presumptive diagnosis while awaiting PCR test results.

Treatment and Therapy

For infections in patients with mild symptoms treatment can be initiated at home with zinc lozenges and mouth wash containing alcohol to reduce the amount of virus in the mouth and upper respiratory tract. Fever should be treated with acetaminophen. More severe cases require hospitalization to provide intravenous fluids and respiratory therapy with oxygen and mechanical ventilation, if necessary. Antiviral agents have been used with varying success. The antimalarials, quinine, chloroquine, and hydroxychloroquine, are also being investigated for effectiveness against the virus. Antibacterials are often used to prevent or treat secondary bacterial infection of the damaged lung tissue of COVID-19 pneumonia patients. Some severe cases seem to show improvement from the infection and then worsen. This late stage illness sometimes seen in severe cases are thought to be the result of continuing and overactive immune response to the infection that can lead to further damage to the lungs. Treatment with corticosteroids has been shown to be of benefit in some patients with this late stage deterioration of the pneumonia.

Prevention and Outcomes

Prevention for the general population is being accomplished by social distancing and quarantine of infected patients or possibly infected patients. Movement of people from countries or areas of increased infection is being completely halted or restricted. A two-week period of quarantine is necessary for infected or possibly infected patients, as well as individuals exposed to an infected patient. Travelers from a country with a high incidence of COVID-19 and cruise ship passengers are also required to self-quarantine for two weeks. Frequent hand washing with soap and water for at least twenty seconds or use of hand sanitizer is strongly recommended. COVID-19 can be inactivated on surfaces by disinfection with 70% ethanol, 0.5% hydrogen peroxide, or 0.1% sodium hypochlorite for one minute. Infected or possibly infected patients should wear masks when seeking medical diagnosis or treatment to lessen the chance of spreading disease. Healthcare workers need to wear gloves, gowns, and N-95 respirators when providing care to infected or possibly infected patients. This protective equipment is also necessary for healthcare workers obtaining nasal and throat swabs for diagnostic testing. Both federal researchers and pharmaceutical companies are developing and testing vaccines to prevent COVID-19, but even with accelerated programs it will likely be 1-2 years before a safe and effective vaccine is available to the public.

Children generally have mild disease; the rare cases of severe disease in children are almost never fatal. Adults have increasing risks of severe disease with older age, underlying diseases, and smoking. The overall adult mortality rate worldwide has ranged from less than 1% to 3%. For elderly patients, the mortality rate is much higher and may exceed 10%. Individuals can completely recover even from severe disease, but some patients recovering from severe disease may shed virus for several weeks and may require longer quarantine. Hospitalized patients should test negative for the virus before being removed from quarantine after discharge from the hospital.

Coronavirus Data

Click here for updated CDC data: https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/cases-in-us.html

Web Sites of Interest

Centers for Disease Control and Prevention

www.cdc.gov

Infectious Diseases Society of America

www.idsociety.org

The Society for Healthcare Epidemiology of America

www.shea-online.org

United States Environmental Protection Agency

www.epa.gov/pesticide-registration/

Citation Types

Type

Format

MLA 9th

Hawley, H. Bradford. "COVID-19 Disease." Salem Health: Infectious Diseases & Conditions, 2nd Edition, edited by H. Bradford Hawley, Salem Press, 2020. Salem Online, online.salempress.com/articleDetails.do?articleName=Infect2e_0144.

APA 7th

Hawley, H. B. (2020). COVID-19 Disease. In H. B. Hawley (Ed.), Salem Health: Infectious Diseases & Conditions, 2nd Edition. Salem Press. online.salempress.com.

CMOS 17th

Hawley, H. Bradford. "COVID-19 Disease." Edited by H. Bradford Hawley. Salem Health: Infectious Diseases & Conditions, 2nd Edition. Hackensack: Salem Press, 2020. Accessed September 16, 2025. online.salempress.com.

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